| 2005-2006 Meeting Minutes
Minutes
of the November 14, 2006 meeting of the Central Illinois Chapter
of the American Meteorological Society (CIAMS)
The Central Illinois Chapter of the American Meteorological
Society (AMS) met at 630 pm on November 14, 2006 at Ruby Tuesday's
in Bloomington IL. 22 people attended the meeting. 22 Members.
Business
Presidents Report
Ernie Goetsch, chapter president, greeted the attendees
and thanked them for coming. He commented on the excellent
speaker set up for the meeting then went on to the CIAMS board
reports.
Secretary's Report
Ed Shimon, reported that he is fine tuning the meeting minutes
from the previous meetings and will be running them through
the board members before submitting them to the AMS for inclusion
in BAMS. Rod Palmer remarked about how anyone would know if
there are any additions to the minutes. Ed responded that
he would make them available to all for comments and corrections
if necessary. They would be available on the CIAMS website
for everyone to view.
Treasurer's Report
Mary Schoen-Peterson, reported that not much activity had
taken place the past 2 months. We paid for the speaker's dinner
at the last meeting. 13 people have paid their dues as of
the start of this meeting. So we have $195 income from dues
so far. That gives us $1674 in the general fund. No conference
fund activity, so we still have $2794 in the conference fund.
She asked that everyone pay their dues as soon as possible.
$15/person.
She mentioned that she was glad to see more people tonight,
since we only had 12 people at the last meeting, and 22 at
the picnic. She requested that everyone make sure they initial
the attendance sheet and annotate whether their dues were
paid or not.
Web site costs will be paid. $195 - It goes to renew our
costs for keeping up our website for the next 2 years.
Committee Reports -
Education Committee - Mike Spinar - He attended an Illinois
State Science Olympiad meeting. He has a few people earmarked
from the Dept of Atmosphere Science. Anyone interested contact
him. Broad topics, anything related to the atmosphere.
Conference Committee - Steve Hilberg - nothing new to report
New Business:
1. Mike Kruk -
Presented results from our submission for chapter of the year
award - CIAMS made the National Honor Roll!! He led a round
of applause for everyone who played a roll. A great deal of
hard work went into the recognition: the AMS conference, all
of the speakers, and education committee accomplishments.
Mike is still working on getting a Meisinger Historic roadside
marker, with Glen and Sam. Honor Roll status lasts for one
year! He said we will probably try again when we have the
next conference, since it seems like that's when we do our
most work.
2. Rod Palmer -
He proposed a suggestion on starting a recruitment program
to boost our membership numbers. Mike Kruk asked if Rod was
interested in being a part of the membership committee, and
everyone laughed. Rod said he was part of other committees
at this time. Rod commented that we have not had any 'new
blood' lately, but Mike pointed out that we have had 6 new
members since March, but they just have not shown up for the
meetings yet. There were comments that maybe the new members
just wanted to vote, and haven't committed to coming to meetings
yet. Getting them to participate is our next challenge.
3. Mike P. -
Diane mentioned the U of I Dept of Atmospheric Science was
starting an undergrad program. We should be aware of when
that starts so we can solicit the undergrads, since they are
typically more active in AMS than the graduate students.
Chris Miller said he had a meeting with the Dept. Head, Mr.
Bob Rauber, and he said that students would not arrive at
the university until the fall of 2008. The program would be
finalized this year, 2007, but no students active in the program
until fall of 2008. A little less than 2 years away.
Ernie agreed that we should get the students involved. It
would benefit them as well as us. Mike agreed. Ernie pointed
out that Chris' visit to the U of I was one of gathering information
on how the NWS office as well as the AMS chapter could work
together with the U of I on projects and meteorological issues.
4. Ernie made a request for any additional new business,
and none was presented. So he proceeded to the speaker of
the night.
Presentation
IMPACT OF THE PACIFIC DECADAL OSCILLATION ON RELATIONSHIPS
BETWEEN AIR TEMPERATURE AND THE ARCTIC OSCILLATION IN THE
US
By Dagmar Budikova
Associate Professor
Department of Geography-Geology
Illinois State University, Normal
dbudiko@ilstu.edu
B.S. in Environmental Studies - Toronto 1994
PhD in Climatology - University of Calgary 2001
Research interests -- Pacific Decadal Oscillation, El Nino,
climate change
Dagmar began the presentation by defining teleconnections
as a persistent atmospheric circulation spanning large geographic
areas, that last several weeks to many years. She discussed
that they are important due to their affects on large scale
flow, like jet streams and atmospheric waves. This can all
lead to changes in our surface weather conditions, especially
during the winter season across North America.
Dagmar indicated that the primary teleconnections that affect
North America are, El Nino Southern Oscillation (ENSO), the
Pacific North American (PNA) pattern, North Atlantic Oscillation
(NAO) or Arctic Oscillation (AO), and the North Pacific (NP)
pattern or Pacific Decadal Oscillation (PDO). These teleconnections
are have their most noticeable influence during the winter
season.
Dagmar went on to further discuss the PDO and described it
as a recurring pattern of climate variability in the tropical
and extratropical Pacific Ocean, but primarily the extratropical.
She mentioned it represents long-term changes in the ocean-atmosphere
system, and it has a Warm phase and a Cool phase. The Warm
phase consists of deep low pressure and cooler than normal
Sea Surface Temperatures (SST) in the North Pacific Ocean,
with an El Nino-like warming of the eastern equatorial Pacific
waters off of South America. Dagmar described the Cool phase
as consisting of warmer than normal SSTs in the North Pacific
under high pressure, with La Nina-like SSTs in the eastern
equatorial Pacific Ocean.
She showed a time series of the PDO from 1900 to October
2006. It highlighted the significant interannual and decadal
variability, with the decadal variability more dominant. Since
1900, the variability has shifted between predominantly positive
to predominantly negative every 10 to 15 years. The last positive
phase ended in the late 90s, with negative phase for the early
2000s. However, current information shows we may have shifted
back to a positive phase since 2002. Dagmar indicated that
more data needs to be examined to determine if that is the
case.
The PDO is primarily characterized by analyzing the SSTs in
the North Pacific Ocean poleward of 20 deg N. Dagmar indicated
that the mechanisms responsible for the PDO are not understood,
and the potential predictability is not known. Basically,
it is not consistently reproduced in global climate models
(GCM). However, she said that when we recognize what phase
we the PDO is in, it does provide some value for improving
seasonal climate forecasts, especially in the western United
States (U.S.).
She discussed the PDO and U.S. winter Surface Air Temperatures
(SAT). The positive PDO had a much better statistical significance,
with the western and eastern thirds of the U.S. in the 95%
correlation level. The Positive phase has a warming SATs in
the western U.S. and a cooling in the eastern U.S. The negative
is somewhat the opposite SATs of the positive PDO, but the
correlation is mostly significant directly along the West
Coast only.
Dagmar went on to define the Arctic Oscillation (AO), indicating
that it is identified by analyzing the Sea Level Pressure
(SLP) poleward of 20 deg N in the North Atlantic. It represents
the state of the atmospheric circulation over the Arctic,
with opposing atmospheric pressure patterns over the Polar
and midlatitudes of the Northern Hemisphere.
The Positive Phase of the AO is highlighted by stronger than
normal low pressure over the Arctic, and stronger high pressure
in the mid-latitudes of the north Atlantic. The pressure distribution
typically creates a stronger jet stream flow from west to
east across the north Atlantic pushing storms quickly across
Canada and keeping the Continental U.S. warmer than normal
during the winter season. The Negative Phase of the AO is
highlighted by weak high pressure over the Arctic with weak
low pressure in the mid-latitudes of the North Atlantic. This
allows a more meridonal flow south through Canada and into
the Upper Midwest and Great Lakes region of the U.S. This
sets the stage for more cold air outbreaks and winter storms
for that area during the winter season.
Dagmar further discussed the AO and its relation to the NAO.
The SLP anomalies of the NAO and AO have almost a .95 or 1.0
correlation over the Northern Hemisphere winter season. That
means that the dipole of high and low pressure in the North
Atlantic is very similar between the Positive and Negative
NAO as the Positive and Negative AO. The Pacific portion of
the AO does not have nearly as strong of a correlation with
the dipole SLP signature.
She presented a slide of the time series of the AO since
1900, focusing on January through March. It indicated that
since 1970, the AO has had a strong tendency to stay in the
positive phase. It does not have as strong of a decadal signature
as the PDO.
When in a positive AO, she should that much of the U.S. is
warmer than normal, with the main statistically significant
area being the eastern half of the U.S. During a negative
AO, much of the U.S. is colder than normal with a majority
of the lower 48 states in the statistically significant range
(95% correlation).
As the main focus of this presentation, Dagmar examined the
combined affect of the AO and PDO on the U.S. winter season.
She accomplished this; by looking at the overall influence
of the AO on the winter SATs, with and without the influence
of the PDO, by analyzing the role played by the PDO on the
relationships between the extreme phases of the AO and SATs,
and by looking at the surface circulation patterns associated
with the observed SAT conditions under various AO/PDO regimes.
She used data from 1900 through 2002, including SAT records
from 344 US climate divisions, and SLP data for the Northern
Hemisphere. She combined the winter timeseries SAT plots of
the AO and PDO in the negative, neutral, and positive phases,
resulting in a 9 box comparison grid. This allowed her to
focus on the affects of the AO and PDO in concert with each
other. When looking at a the SAT differences between a positive
and negative AO, while combining it with a Neutral PDO, there
are signals that stand out more prominently. The warm bias
of the SAT difference of the positive and negative AO is reduced
in coverage from the eastern 2/3rds of the U.S. to just the
south and southeast US. When doing the same comparison with
the SAT differences between a Positive and Negative PDO during
a neutral AO, the strong cold bias of the southeastern US
was accentuated.
When doing a similar analysis on the Positive PDO during
a Negative AO, Dagmar found that there was not a significant
effect on the US SATs except for the SW US being slightly
warmer, and the far NE US being colder than normal.
Further SAT analysis of the Negative PDO with the Negative
AO showed a strong cold bias across the northern plains of
the US. She found much colder conditions from Montana, through
the Dakotas, to Wisconsin. The rest of the US was not statistically
significant.
A look at the Positive PDO during a Negative AO showed a
strong warm bias for the upper Midwest and the western US.
Analyzing a Positive PDO and a Positive AO indicated a more
scattered solution. There were very few statistically significant
areas, with a small area of warming in the intermountain west
and some cooling in the northeast US.
A Negative PDO combined with a Positive AO gave a correlation
for colder than normal SATs along the west coast of the US,
with very weak signals elsewhere.
Dagmar also looked at the effects of both extremes of the
PDO during a Positive AO and found that overall, there is
a strong warm bias for the west coast, and a strong cold bias
for the Ohio Valley and the northeast US.
She analyzed the SLP patterns in much the same way as the
SAT patterns. She wanted to see if similar correlations could
be found. When looking at the Negative AO combined with a
neutral PDO, the effects of the Negative AO were enhanced.
There was an abnormally strong Arctic High, along with a strengthened
Aleutian Low. The Bermuda High and Icelandic Low were slightly
weakened during a Negative PDO.
Going further, she compared the SLP anomalies during a Negative
AO with the Negative PDO. It indicated a stronger than normal
high pressure in the Hudson Bay and James Bay areas of Canada,
allowing more frequent surges of cold air into the Upper Midwest
of the US. Statistically significant cooling was indicated
from the Northwest US through Wisconsin.
PDO SLP differences during a Negative AO showed lower pressures
across Canada and the Aleutians, which would create a more
southerly flow across the western US. This correlated to warmer
than normal conditions for the western US and the Upper Midwest.
PDO SLP differences during a Positive AO were not as statistically
significant. Dagmar noticed a strengthening of the Arctic
low and a weakening of the Aleutian low, which tended to have
little affect on the normally expected effects of the Positive
AO.
When looking at the strongly Positive PDO and strongly Negative
PDO during a Positive AO, there was a strong correlation for
a deeper Aleutian Low and Canadian High, which set the stage
for significantly warmer than normal SATs for the western
US and colder than normal SATs for the northeast US.
Dagmar's final conclusions were that the PDO clearly has
an affect on the SAT tendencies across the United States during
both extremes of the AO. The north-south dipole structure
of the SLP field was altered during the extreme phases of
the PDO.
She concluded that during a positive AO, the PDO most significantly
alters the SAT anomalies west of the Cascades, in the Ohio
Valley region, and along the northeast coast of the US. During
a Negative AO, she concluded that the PDO extremes most significantly
alter the SAT anomalies across the northern Great Plains,
and throughout the western US.
Questions from the attendees:
What about El Nino in combination? She said that would be
too complicated for her right now.
Which affect drives the other, the circulation or the ocean?
We don't know for sure.
During a Positive AO, the stratosphere is colder? Yes, due
to the strong Arctic low that develops.
Adjournment
After questions the meeting adjourned around 9:15 PM.
Upcoming Meeting
The next meeting of the CIAMS will be on January 25, 2007
in Champaign.
Ed Shimon, Secretary, 2006-2007.
Minutes
of the May 2, 2006 meeting of the Central Illinois Chapter
of the American Meteorological Society (CIAMS)
The Central Illinois Chapter of the American Meteorological
Society (AMS) will meet on May 2, 2006 in Decatur, Illinois.
Minutes
of the March 16, 2006 meeting of the Central Illinois Chapter
of the American Meteorological Society (CIAMS)
The Central Illinois Chapter of the American Meteorological
Society (AMS) met on March 16, 2006 at Ruby Tuesday Restaurant
in Bloomington, Illinois. 33 people attended the meeting.
Business
Presidents
Report
Mike Kruk, chapter president, announced that elections would
be held at our next meeting on May 2nd, and that
the nominating committee was being formed to solicit nominations.
Votes prior to the meeting can be by mail or e-mail.
Votes also will be taken at the next meeting.
Treasurer’s
Report
Llyle Barker, reported that as of March 14, 2006, twenty-eight
full members have paid their dues for the 05-06 meeting year
for an Income of $420. As a reminder, you must pay your
dues in order to vote.
Aside from reimbursement for the January meeting speakers
meal, the General Funds balance is $1440.50. No conference
fund actions have been made since the last meeting.
Education/Public
Outreach
On March 4th, Mike Kruk, Sam Shea, and Leslie Ensor
of the CIAMS handed out 20 chapter brochures and spoke about
benefits of joining the chapter at the Emergency Manager and
Media Severe Weather workshop hosted by the WSFO in Lincoln,
Illinois.
Bob Scott and Bob Rauber each taught 2 classes of boy scouts
at Holy Cross School in Champaign, Illinois at an annual Boy Scout
education event designed to help the scouts attain various
badges. About 80 boy scouts earned their weather badge.
The Education Committee administered the Urbana Regional portion
of the Science Olympiad Exam. The committee is working with
the Lincoln Weather Service Office to draft the Illinois State
Olympiad Competition on April 29th. The National
Competition will be held in May.
Annual
AMS Meeting
Mike Palecki represented the Chapter at the Annual Meeting
of the American Meteorological Society, attending the breakfast
meeting and presenting our chapter poster. He reported
that next year there will be a poster competition.
Upcoming
Meetings
The next meeting of the CIAMS will be held in Decatur, Illinois on Tuesday, May 2nd.
Jay Searles, a local broadcast meteorologist, will speak
at our final meeting of the 2005-2006 fiscal year. Again annual
elections will be held at that meeting
Presentation
James Auten, lead forecaster at the Lincoln Illinois National
Weather Service Office (ILX) presented a talk entitled “A
Look at the Severe Weather Warning Operations inside the National
Weather Service”. His talk included detailed information
on 1) the processes involved in preparing for successful operations,
2) staffing positions, 3) the operational plan, 4) factors
to consider in the days preceding a severe weather event,
during the event and actions taken following the event.
Finally, 5) examples of operations from an event on June 29,
1998 when the NEXRAD Radars were present, but computer support
was limited, and from a recent March 12-13, 2006 tornado outbreak
affecting the local Springfield IL area.
The
process of severe weather warning operations begins with the
education of the staff regarding severe weather, initially
at universities, and then as employees attending workshops
and seminars, reviewing literature and researching past severe
weather outbreaks. Training of staff continues formally
by attending Radar School and other NWS schools, and informally
by replaying self-paced or real-time simulations from archived
data on the Warning Event Simulator (WES). Real-time
operations i.e. real- time experience is of course a large
component of staff training, as anything can happen.
Verification of forecast warnings are made to complete the
training. This includes damage surveys (how many of
the 20 counties under the warning had severe weather) and
post event reviews (using WES): How well did we do?
What we could have done better? What was missed?
What distracted us?
The
positions involved in the warning process include: the
Warning Coordinator (WCO), who coordinates and directs
the operations, ensuring proper staffing levels, keeping track
of warnings and statements and filling in when necessary;
the Warning Meteorologist, who evaluates the radar,
satellite, lightning, surface data, and spotter reports, and
who issues necessary warnings and statements (if the warning
area is large or complex enough, sometimes 2 or 3 are necessary);
the Communications Person (COP) who handles all in-coming
phone calls, National Warning System (NAWAS), phone
and e-mail reports, and advises county emergency coordinators
of threats; the communications person or the Console Replacement
System (CRS) Monitor who ensures that all warnings and
other statements are getting onto the CRS, i.e. to the NOAA
Weather Radio; the Ham Radio Volunteers (HAM)
who broadcast warnings and statements using amateur radio
and who solicit and collect reports from Emergency Operation
Coordinators (EOCs); the Long Term Forecasters, (LTF,
two for the 08-16 LST and two for the 20-04 LST hour shifts)
who create and disseminate forecast products; the Short
Term Forecaster (STF, manned 24 hr/day) who is the meso-analyst,
and also updates forecast products and issues short term and
terminal forecasts; the Hydrometeorologist Technician (HTM)
/ intern who coordinates the upper air launches and collects
data from the Surface Weather Operational Stations (SWOPS)
and NWS cooperative sites and issues routine climate forecasts;
the Electronic Technician (ET) who insures equipment
is working properly and stands by to fix what is necessary
(AWIS, Upper Air, Computer), the Flash Flood Analyst who
monitors flash flood potential, radar precipitation products,
real-time precipitation and flood reports (what counties and
basins are susceptible to flash flooding), and the Shift
Leader who coordinates between the Warning Coordinator
and the staff, and who attempts to minimized distractions
to the staff.
In the days leading up to a severe weather event, the public,
media, and Emergency Managers are notified of a severe weather
potential via the Hazardous Weather Outlook (HWO), e-mail,
and other weather discussions. Staffing for the event is planned.
Conference calls are conducted with Emergency Managers and
the media for Moderate and High Risk Outlooks.
For a minor event that involves only one sector of the region,
5 – 7 staff are usually used: the WCO/COP, the Warning Forecaster,
the STF/Meso-Analyst, the HMT/Intern, the CRS Monitor, the
LTF (if needed) and the Flash Flood Analyst (if needed).
For a moderate event that involves two sectors, 4-6 additional
persons are added: an additional Warning Forecaster and a
COP to assist each Warning Forecaster; and an ET. For
a major event that involves 2 – 3 sectors of the warning region,
11 - 13 staff are used (adding an additional Warning Forecaster
and a COP, plus 2-3 HAMS. There are only 22 employees at the
ILS-NWSFO in total, so a significant proportion of the staff
is involved for major severe weather outbreaks, both on the
day of the event and on the days following the event.
Following a severe weather event further planning is needed:
additional reports are collected, preparations are made for
damage surveys (if needed) and the damage surveys are accomplished;
evaluation of staffing needs is performed, particularly if
more severe weather is imminent. Media calls are fielded,
necessary reports are prepared, and web pages are created
for the Internet to disseminate information to the public
and emergency managers.
A number of factors are considered in planning by the warning
coordinator that can affect his/her decisions. Is the
environment tornadic and could this change? What type
of storm does the Warning Coordinator envision when considering
the synoptic, mesoscale and storm environment? As the
event evolves, does this conceptual model match what is happening?
What is the history of the storm? What type of
damage (hail, wind, rain) reports are being received once
the storm has reached the forecast area? What is the
time of day, the day of the week, the time of the year?
Are people asleep, on their way home from work, are there
leaves on the trees? How will high winds, heavy rains
or hail affect the region?
Distractions can affect the performance of the staff during
a severe weather event and these are monitored by the Shift
Leader: Equipment problems, communication, computer
or radar malfunctions can be very disruptive. Bad /
late reports can result in staff taking extra time to consider
the implications of the report, or may mislead the staff particularly
if other distractions are present. Fatigue, hunger,
and personal issues can distract personnel. Music can
be distracting. Life threatening reports, particularly
when they are located in the region where a staffer’s family
resides can be another distraction.
Mr.
Auten then proved two examples of the warning process in full
operation. The first of these was a bow echo / derecho
event of June 30, 1998. On this date, a line of storms
in Iowa that had produced wind damage
and tornadoes was approaching central Illinois. A large
area of ground-relative radial velocities in excess of 64
kts, as observed by radar was racing towards the area. The
primary operational team consisted of three staff members,
one to concentrate on the radar with the single PUP station
present, one warning decision maker who communicated with
the Emergency Managers, and one person to key the warnings
and statements on the single PC present. Data from 3
NOAA radars, 1 satellite, and 1 upper air site were available
to the trio. Bow echoes are known to produce tornados,
especially along the leading edge. In this case the
leading edge was extensive, spanning nearly the entire county
warning area (CWA). This prompted the trio to question
where warnings should be issued to best represent the danger
posed by this bow echo. The team wanted to heighten
awareness of the approaching line, and made a bold move by
over-warning. They issued multiple county tornado warnings
(so that the sirens would deploy) all along the line, in each
of 35 counties. In the end, the derecho produced 7 tornadoes
and all 35 counties in the ILX-CWA experienced some damage.
The
second example presented by Mr. Auten focused on the Springfield
Illinois tornado event of March 12, 2006. On this date,
a dangerous supercell thunderstorm was approaching.
Over the intervening 8 years, staffing, computer power and
access to observational resources had expanded, and more precise
locations for tornado warning could be issued. The sequence
of events is as follows. Early Sunday March 12, an e-mail
was sent to Emergency Managers for a conference call at noon.
There was a high risk of severe weather over
Central Illinois. The Storm Prediction Center requested 18Z and 21Z upper air radiosonde flights. Additional conference
calls were held at 2 pm and 6 pm. The first Tornado
Watch was issued around noon
local time until 10 pm covering a large area of the country
from Oklahoma to Central Illinois. Staffing was increased
from 3 to 5 around noon. Storms were present to the
west and southeast, so two warning sectors were established.
Staffing was increased to 8 people by mid-afternoon.
The
weather was quiet from 4 to 7 pm. But by 7 pm, two supercells
had merged into one massive supercell in eastern Missouri / western Illinois and
was approaching Springfield IL in the southwest quadrant of
the CWA. Additional storms were moving northeast towards
the northwest areas of CWA. Springfield TV station WICS
and Decatur TV station WAND began broadcasting live weather
reports. The NWS NOAAA Weather Radio broadcast went
live on SPI NWR. A situational awareness screen was
activated at the Weather Service Office to monitor local TV
broadcasts, and to make sure that warnings were properly disseminated.
By 8 pm staffing had increased to 9, including the ET.
Two NWS employees that lived in Springfield were contacted.
2-3 HAM volunteers were present during entire event.
Once the first tornado warning was sent out, the entire staff
was busy. Sixteen (16) of 22 employees worked at some
point during the event. A warm front moved north late
in the day, but quickly. The main supercell entered
the CWA in southeastern Scott County at 7:29 pm and exited CWA from southeastern
McLean County around 9:30 pm. During the event there were 6 confirmed tornadoes in the CWA, one
F1 and five F2 tornadoes (2 in Springfield).
Severe weather came in 4 waves, with 2 more waves after the
Springfield supercell. Warning Operations lasted from
noon on Sunday March 12 until 8 am Monday March 13.
Two damage surveys were conducted that Monday and one on Tuesday.
Many in the office also had worked severe weather operations
on Saturday evening March 11, 2006. It had been
an eventful week for the ILX Weather Service Office.
Adjournment
After questions the meeting adjourned around 9:45 PM.
Nancy
Westcott, Secretary, 2005-2006.
Minutes
of the Jan 26, 2006 meeting of the Central Illinois Chapter
of the American Meteorological Society (CIAMS)
The Central Illinois Chapter of the American Meteorological
Society (AMS) met on January 26, 2006 at Ryan’s Steakhouse
in Champaign, Illinois. 13 people attended the meeting.
Business
National
News
Mike Kruk, chapter president, announced that the December
2005 issue of BAMS featured two short articles highlighting
the CIAMS in addition to our regular meeting minutes. The
first, entitled “Modern/Future Extreme Cold Air Outbreaks”,
discussed was based on a talk given by Steve Vavrus of the
University of Wisconsin – Madison during the 2nd
Midwest Severe and Hazardous Weather Conference in October.
The second, “Association Between Seasonal Cycles of Teleconnections
and Tornado Frequency in the United States”, featured material
presented by Patrick Frances of Bowling Green State University
at the July Central Illinois/Central Indiana AMS joint chapter
meeting. For reference, the two articles are on pages 1721-22
and 1723-25, respectively. This is good news for the organization’s
bid to become AMS “Chapter of the Year”. Our materials will
be submitted by May 1st and we will find out the
winner of the award in October.
Treasurer’s
Report
After reimbursing several speakers, we have $1407 in our general
fund. In addition, Steve Hilberg noted that the final total
for the Midwest Severe and Hazardous Weather Conference is
in. We spent $2791, for a $903 loss.
Education/Public
Outreach
On March 4th, several members of the CIAMS will
hand out chapter materials at the Emergency Manager and Media
Severe Weather workshop in Lincoln, Illinois. This will serve
to increase recognition of and encourage interest in the local
chapter. In addition, the Education Committee will administer
the Urbana Regional portion of the Science Olympiad Exam.
The committee will work with the Lincoln Weather Service Office
to draft the Illinois State Competition on April 29th.
Upcoming
Meetings
The next meeting of the CIAMS will be held in Lincoln, Illinois
on Thursday, March 16th. James Auten from the Lincoln
Weather Service Office will discuss the severe weather warning
process at the Weather Service. Jay Searles, a local broadcast
meteorologist, will speak at our final meeting of the 2005-2006
dues year. Annual elections will be held at that meeting,
on Tuesday, May 2nd. Stay tuned for more information!
Presentation
Eric Snodgrass, master’s degree candidate from the Department
of Atmospheric Sciences at the University of Illinois gave
a talk entitled, “Synergizing High-Resolution Satellite Data
and Radar Data to Assess Trade Wind Cloud Precipitation”.
Eric was the radar coordinator for the Rain In Cumulus over
the Ocean (RICO) field campaign and is an expert in satellite
remote sensing with GIS-based applications.
Trade wind cumulus clouds are ubiquitous over the tropical
oceans. New, higher resolution satellite data is beginning
to show just how widespread the clouds are. However, important
questions remain about their role in the global thermal, radiative,
and moisture budgets. Chief among these are the questions
of which clouds precipitate and how much. Since the clouds
are typically far from land, the precipitation must be inferred
by using one of three methods : 1) relating the infrared
thermal brightness temperature to precipitation rate,
2) passively measuring the microwave absorption of the clouds,
or 3) using the Tropical Rainfall Measuring Mission (TRMM)
to actively scan microwave absorption of clouds. However,
these methods are not useful for measuring trade-wind Cu,
because they are warm, shallow, and typically, sub-pixel in
scale.
The RICO experiment was designed specifically to study the
microphysics, scale, frequency of occurrence, and generation
mechanisms of trade-wind cumulus. In addition to aircraft
measurements of the cloud microphysics and environmental conditions,
the Scanning S- and Ka- band Dual-Polarization radar assembly
(S-POLKa) was located on the island of Barbuda. Various satellite
products also were used for this study, including the 275
m resolution Multi-angle Imaging SpectroRadiometer (MISR)
imagery.
The main purpose of this study was to correlate the 10 cm
radar returns with cloud pixels sampled from the MISR. This
was done at 10:45 am local time, which allowed the satellite
and radar data to be matched in time. The radar volumes were
then mapped to the MISR pixels using a 3-step procedure. First,
the radar data was geolocated in three dimensions using a
sounding-derived refractive index. Next, the radar’s Velocity-Azimuth
Display (VAD) wind profile was used to shift pixels to account
for drift due to the background flow. Once the MISR and S-POLKa
data were time-matched, the radar data were resampled to the
MISR grid. Then contaminated echoes (e.g., local island effects,
birds) were removed using a combination of image masks, differential
reflectivity polarization, and radial velocity quality control
procedures. Finally, the S-band change from Bragg to Rayleigh
scattering at 5 dBZ was used as a threshold to eliminate all
non-precipitation echoes.
The majority of the cloud pixels analyzed using this method
showed no precipitation, despite the considerable vertical
extent of many of them. Roughly 2 percent of the cloudy pixels
had reflectivities greater than 24 dBZ, corresponding to a
1 mm/hr rainfall rate. Out of the 3 organizational patterns
of trade wind cumulus, wind parallel bands, multicellular
clusters, and outflow bands, outflow bands produced the most
rain and wind parallel bands, the least. Overall, the reflectivities
indicate that the region experiences an average of .75 mm
day-1 of rain, with an intensity peak occurring in the early
morning hours. Overall, this means that trade wind cumulus
systems are 11-15% efficient at returning latent heat to the
ocean, a finding of great importance to the numerical modeling
and climate communities.
Adjournment
After
questions the meeting adjourned around 9:15 PM.
Mike
Spinar, Secretary, 2004-2005 for Nancy Westcott, Secretary,
2005-2006.
Minutes of the December 6,
2005 meeting of the Central Illinois Chapter of the American
Meteorological Society (CIAMS).
The Central Illinois Chapter of the American Meteorological
Society (AMS) met on December 6, 2005 at Marcia’s on the Waterfront
in Decatur, IL. 14 people attended
the meeting, which was rescheduled from November 15th
due to a severe convective weather threat.
Business
Mike Kruk, Chapter President, announced that Dr. Michael Palecki,
Regional Climatologist for the Midwestern Regional Climate
Center (MRCC), will serve as the CIAMS chapter representative
at the local chapter breakfast held during the annual meeting
of National AMS. In addition to our summer picnic, Regional
Conference, Science Olympiad involvement, and bi-monthly meetings,
the Chapter would also like to accomplish the following by
May 2006:
(1)
Display our local chapter poster at the AMS Annual Meeting,
(2)
Perform at least one additional service or outreach opportunity,
(3)
Unveil the new chapter logo designed primarily by Sam Shea
from the Midwestern Regional Climate Center.
The treasurer’s report was delivered by Mike Kruk on behalf
of Llyle Barker. To date, we have had 23 dues-paying
members. After the payment of a fee for our website
host, we have approximately $1400 remaining in the account.
An additional small sum must be paid to cover remaining
expenditures from the Regional Conference. The Conference
is expected to break even once all the bills are tallied.
Leslie Ensor, member of the Program Committee, reported that
the next meeting would be in Champaign on January 19. Dan
Smith from the National Weather Service Office in Lincoln,
Illinois is the invited speaker for the meeting. James
Auten, also from the National Weather Service in Lincoln,
will be speaking at the Bloomington meeting, currently scheduled
for March 16.
Mike Spinar, chair of the Education Committee, reported that
he had attended the first meeting of the 2006 Illinois State
Science Olympiad season. The topic this year is on climate
systems and change. He is looking for interested volunteers
to help design and proctor the exam. More information
on dates and times will be posted on the website as they become
available (http://www.c-il-ams.org).
A raffle was then held to give away various publications written
by Dr. Theodore Fujita, and previously kept in his personal
library, and donated to the Chapter by his son, Kazuya Fujita.
Six packets of publications, including one hardbound
book, were raffled at the meeting. The event was a big
hit among those in attendance.
Presentation
Dr. Carl Bernacchi, Plant Biologist from the Illinois State
Water Survey in Champaign, Illinois, gave the
invited talk for the evening. His talk was entitled,
“Carbon and Water Fluxes from Corn and Soybeans – Responses
to Atmospheric Change.”
Dr. Bernacchi talked about his work detailing leaf and canopy-scale
interactions between the atmospheric boundary layer and corn
or soybean plants. The corn and soybean rotation comprises
the largest ecosystem in North America, so this research has
dramatic implications for the concentrations of greenhouse
gasses.
The first part of the presentation dealt with the SoyFACE
project, which studies leaf responses to elevated carbon dioxide
and ozone. These elevated concentrations are obtained
by pumping carbon dioxide and ozone from tiny holes in a hexagonal
ring of PVC piping around the field. The gasses are
exuded from the holes in such a way as to blow over the field
at a uniform concentration. Instruments at 16 weather
stations measure a wide range on micrometeorological variables,
including, soil temperature, incoming and outgoing radiation,
canopy temperature, air temperature, humidity, and wind speed.
These measurements are used to determine the net radiative
flux, the sensible heat flux, and the heat flux through the
soil. The latent heat flux is determined using the residual
in the energy balance.
The study indicates that the canopy is warmer in the high
ozone and high CO2 treatments. Both elevated
carbon dioxide and elevated ozone regions of the canopy show
lower latent heat fluxes. Stomata are the holes in the
leaf surface that allow carbon dioxide and water vapor to
diffuse in and out of the leaf. Plants adjust the size
of the stomatal openings to regulate gas exchange between
the leaf and the atmosphere. Thus, a higher stomatal
conductance allows more water vapor to be transpired. However,
in the case of elevated carbon dioxide, the leaf area of the
plants increases while the conductance decreases. On
the other hand, in the case of elevated ozone concentrations,
the leaf area decreases. The highly reactive ozone damages
the plants, whereas the carbon dioxide provides more raw materials
for photosynthesis.
The second portion of the talk dealt with the measurement
of agricultural sequestration of atmospheric carbon. As
plants grow, they store vast quantities of carbon above and
below ground. If this carbon is stored long-term below
ground, it leads to a removal of carbon dioxide from the atmosphere.
However, 80% of the carbon assimilated via photosynthesis
is contained within the grain material, which is not sequestered
long-term. Therefore, the question arises as whether
no-till agriculture might be a solution to the greenhouse
gas induced warming predicted by climate models.
A series of instrumented towers are used to measure carbon
fluxes into and out of corn and soybean fields. The
fluxes, obtained through eddy covariance techniques, reflect
a more precise average than typical point measurements of
soil carbon. After three corn/soybean rotations and
controlling for modern agricultural practices that release
carbon, Dr. Bernacchi found that there was a slight sequestration
of atmospheric carbon. If no-till agricultural practices
were universally adopted, this would equate to 20 million
metric tons a year. This value, 1.5 percent of the annual
U.S. output, would help the greenhouse gas situation, but
not solve the predicted problem.
After
questions, the meeting adjourned around 9:10 PM.
Mike
Spinar, Secretary, 2004-2005 and Nancy Westcott, Secretary,
2005-2006.
Minutes
of the September 14, 2005 Meeting of the Central Illinois
Chapter of the American Meteorological Society.
Meeting Overview
The September 14, 2005 meeting of the Central Illinois Chapter
of the American Meteorological Society (CIAMS) was held at
the Bonanza Restaurant in Lincoln, Illinois. The meeting began at
approximately 7:45 pm, after everyone had finished their meals.
There were 23 people were in attendance. After the business
portion of the meeting, Steven Hilberg, Director of the Midwestern
Regional Climate Center within the Illinois State Water Survey in Champaign, IL gave a talk entitled, “Deja
Vu All Over Again - A Climatological Renaissance in the U.S.”
The meeting then concluded shortly after 9:00 PM.
Business
Mike Kruk researcher at the Illinois State Water Survey and
CIAMS President opened the meeting by acknowledging those
who helped with the first CIAMS Chapter picnic which was held
on August 28th at Weldon Springs State Park near Clinton, Illinois. Mike reported
that the picnic was very successful and hoped that it was
the first of many future picnics. More than 25 members,
family, and friends attended the picnic.
Llyle Barker presented the treasurer’s report. The Chapter’s
account balance is currently $3141, of which $1862 is earmarked
for the 2nd Midwest Extreme and Hazardous Weather
Conference in October 2005. Since the last meeting,
money was spent on picnic related items, and for the conference,
on the design of the Conference Logo and on reminder postcards
labels and stamps. Prior to the meeting, there were
13-paid chapter members. There was some discussion that
the Program and Activities Committee, along with the Executive
Committee is interested in bringing in one outside speaker
per year. This would cost approximately 300-400$, which
is the expected funds raised by dues collection. Additional
discussion will take place over the course of the next few
weeks to allocate funds to each Standing Committee, and to
organize and develop a working budget for the current fiscal
year.
Steve Hilberg, chair of the 2nd Midwest Extreme
and Hazardous Weather Regional Conference, reported that the
conference will take place in Champaign, IL on 14-15 October
2005. Twenty-four abstracts were accepted as oral presentations
for the conference. The three invited speakers (Dr.
Paul Kocin, Tim Marshall, PE, and Dr. Morris Weisman) are
set to come. To date, 22 persons have registered for
the conference. The early registration deadline is September
22nd, and thereafter, the cost of the registration
increases to $125 from $95.
The officers are also soliciting interested persons to design
a chapter logo and a chapter poster highlighting the people
and activities that have contributed to the success of the
CIAMS during the past several years. The logo would
be included on the poster. The poster would be excellent
for presentation at the AMS annual meeting in January as well
as the Midwest Extremes Conference in October. It would also
serve to illustrate why the CIAMS should be selected as “Chapter
of the Year.” Please submit any photos or written documentation
you may have to Tom Bellinger or Mike Kruk.
Nancy Westcott gave a brief report on behalf of Mike Spinar
for the Education and Public Outreach Committee. We
received an announcement from the American Meteorological
Society regarding AMS/Industry Minority College Scholarships.
Please contact Mike Spinar for further information.
Leslie Ensor represented the Program and Activities Committee
at the meeting. She reported the planned dates for upcoming
CIAMS meetings:
Date
Day
Location
Speaker, affiliation
November 15
Tuesday, Decatur,
Dr. Carl Bernacchi, ISWS
January 19
Thursday, Bloomington
TBA
March 15
Wednesday Champaign
TBA
May 2
Monday
Clinton
TBA, Annual Election Mtg
Invited Talk
Steven Hilberg, Director of the Midwest Regional Climate Center
at the Illinois State Water Survey, Champaign gave a talk
entitled, “Deja Vu All Over Again - A Climatological Renaissance
in the U.S.” He presented a historical look at weather
and climatological observations dating from the early 1600
to the present. Steve presented a time line of the main
agencies that have overseen weather and climate data and its
uses, as well as a view of the more recent history of the
ebb and flow of climatological services, in other words, a
“meteorological climatology”.
In recent years, the internet has made accessing climate data
easier for researchers, forecasters, and the public user.
Futher more powerful computers allow for data storage
and for more easily readable and useful product displays.
Near real-time data are more readily available for input
into weather and climate forecasting models, for input into
climate products, and for dissemination to the public.
Recent climatological events, such as El Niño in 1997-98,
the spring / summer 2005 corn-belt drought, and the hurricane
Katrina disaster all have elevated the awareness of the effects
of weather and climate on society. The utility of climate
monitoring to the NWS, the USDA, the media and general public
has been best exemplified in recent years by the advent of
“The Drought Monitor”, a joint venture of the Departments
of Agriculture (Agricultural Weather Center) and Commerce
(NOAA/CDC, NOAA/NWS, NOAA/NCDC), with assistance from other
Federal Agencies, the Regional Climate Centers (RCCs) and
State Climatologists among others. There are encouraging
signs regarding interest in and funding for climate services:
the National Weather Service has created a Climate Service
Division, the Climate Reference Network (CRN) has been funded
well enough that 76 sites are now operating, funds have been
allocated to modernize the NWS Cooperative Stations, nearly
every state now has a state climatologist program, and also
common data bases (such as the Applied Climate Information
System) are being developed for utilization by the National
Weather Service, State Climatologist Offices and the RCCs.
Climate services in its many forms appear to be alive and
well at this point in time.
Minutes
of the July 28, 2005 Meeting of the Central Illinois Chapter
of the American Meteorological Society.
Meeting Overview
The July 28, 2005 meeting of the Central Illinois chapter
of the American Meteorological Society (CIAMS) was held in
conjunction with the Central Indiana Chapter of the AMS at
the Beef House in Covington, Indiana. The meeting began at
approximately 6:45 pm, after food was served. Approximately
41 people were in attendance, 15 CIAMS members, and 26 guests.
After the business portion of the meeting, Dr. Patrick Francis
of Bowling Green State University gave a talk entitled,
“Association Between Seasonal Cycles of Teleconnections and
Tornado Frequency in the United States.” The meeting then
concluded at 8:30 PM.
Business
Mike Kruk began the new membership year of the CIAMS with
a presentation of the new officers. Mike is the new president,
taking over for Chris Miller. In addition, Tom Bellinger is
taking over the President-Elect position from Mike, Nancy
Westcott is the new secretary, replacing Mike Spinar, and
Llyle Barker is taking over the treasurer’s position from
Maria Peters.
The CIAMS is having the first Chapter Picnic Sunday August
28th at Weldon Springs State Park near Clinton,
Illinois. The Chapter will provide the meat, buns, and the
shelter. Attendees are asked to bring a dish or treat to pass.
Interested persons are encouraged to visit the Chapter web
site,
http://www.c-il-ams.org/picnic.html
for further details.
The new business year means that it is time to set up committees.
All members are encouraged to volunteer. If you are interested,
please contact the chairperson of one of the following committees:
Program
and Activities: Dave Kristovich (dkristo@uiuc.edu)
Education and Public Outreach: Mike Spinar (mspinar@uiuc.edu)
Membership: Ed Kieser (edkieser@will.uiuc.edu)
Conference: Steve Hilberg (hberg@uiuc.edu)
Student:
To Be Determined
The new student committee will be involved in several activities
this year, including coordinating the student poster competigion
at the Midwest Extreme and Hazardous Weather conference. Suggestions
for other activities this year include the design of a CIAMS
Chapter logo and the coordination of a photography competition
for all CIAMS members. The newly formed committee is currently
in need of members and a chairperson. Please contact one of
the officers if you are interested. Please contact Mike Spinar
(mspinar@uiuc.edu),
if you would like to help specifically with the student poster
competition.
On June 2, 1924, Dr. Clarence Leroy Meisinger of the Weather
Bureau and Lt. James T. Neely were killed when their balloon
exploded after being struck by lightning in a thunderstorm
near Monticello, Illinois. The researchers were investigating
the path of airstreams through mid-latitude cyclones. The
Meisinger Award is given each year by the American Meteorological
Society (AMS) to recognize the tragic death of this scientist
who died investigating the atmosphere. The CIAMS wishes to
place a historical marker near the crash site in Monticello.
A marker costs approximately $1800, half of which will be
contributed by the AMS. It is up to the CIAMS to raise the
other half of the money. Contact Tom Bellinger (Bellinger@iema.state.il.us)
if you have any ideas.
The officers are also soliciting interested persons to design
a chapter poster highlighting the people and activities that
have contributed to the success of the CIAMS during the past
several years. This poster would be excellent for presentation
at the AMS annual meeting in January as well as the Midwest
Extremes Conference in October. It would also serve to illustrate
why the CIAMS should be selected as “Chapter of the Year.”
Please submit any photos or written documentation you may
have to Tom Bellinger.
Llyle Barker gave the treasurer’s report. The Chapter’s account
balance is currently $4000, of which $2800 is earmarked for
the 2nd Midwest Extreme and Hazardous Weather Conference
in October 2005. The new dues year has started; dues payment
reminder notices will be sent out soon. Annual dues are $15
for general members and $6 for students.
Mike Spinar gave the report for the Education and Public Outreach
Committee. Several student members on the committee have either
graduated or pursued their careers outside Central Illinois,
so new members are needed. The group will be working on many
projects this year, including organizing and overseeing the
student poster competition at the Midwest Extreme and Hazardous
Weather Conference.
Invited Talk
Dr. Patrick Francis of Bowling Green State University gave a talk entitled,
“Association Between Seasonal Cycles of Teleconnections and
Tornado Frequency in the United States.” During this talk,
he presented a new tornado climatology based on tornado paths
rather than on tornado reports, and also he examined the possible
relationship between tornado frequency in the United States
and teleconnective forcing mechanisms, such as El Nino/Southern
Oscillation (ENSO) and the North Atlantic Oscillation (NAO).
The author began with a review of past research, discussing
the climatologies of Brooks (1999) and Concannon, Brooks,
and Doswell (2000). Both studies determined the frequency
of occurrence of tornadoes using a similar methodology. Brooks
(1999) examined all tornadoes, while the later Concannon et
al. (2000) study considered the occurrence of strong F-2 or
greater tornadoes on the Fujita Scale. The authors divided
the country into 80 square kilometer grid boxes and examined
days of tornado reports within each grid. The data were smoothed
spatially and temporally. Maxima in tormado frequency
were found in Colorado, Florida, and the traditional Central
Plains “tornado alley” region of the United States.
These
two studies did not examine the possible relationship between
tornado frequency and teleconnective forcing mechanisms.
Dr. Francis referred to the Schaefer and Marzban (2000) paper
as one study that examined the relationship between tornadoes
in the United States and teleconnections. This study found
no statistical significance between tornado frequency and
teleconnective forcings.
Dr.
Francis reviewed the methodology employed by Schaefer and
Marzban (2000) and drew inspiration from his own experiences
as a storm chaser, to develop a new statistical approach to
the same topic. He re-examined the same data used in the aforementioned
climatologies. Instead of looking at individual days of tornado
reports, however, he investigated actual tornado paths using
statistical techniques borrowed from the U.S. Geological Service.
Employing Kernel Home Range and Least Squares Cross Validation
techniques, he produced a map of tornado probability on a
1 km grid. This grid suffered from population biases
in tornado reporting. For example, there were elevated
probabilities near larger cities such as Houston, TX; Oklahoma City, OK; and Tampa Bay, FL. Thus, these data were
smoothed, resulting in a plot that compared favorably with
Brooks (1999) and Concannon et al. (2000).
Upon dividing the data into subsets based on positive, neutral,
and negative ENSO and NAO anomalies, fascinating patterns
began to emerge. For all tornadoes, the largest frequency
of occurrence appeared during times when both ENSO and the
NAO were in neutral phases. The smallest tornado probabilities
took place during positive ENSO and positive NAO periods.
Further examination of each of these possible phases showed
that the spatial distributions of the tornado frequency also
changed. There was a decrease in total frequency of occurrence
when both ENSO and the NAO were negative, with peaks in Colorado,
Florida, and locations just west of the Mississippi River
in Arkansas and Louisiana. A teleconnection consisting of
a positive ENSO and a negative NAO phase showed an increase
in tornado probability, with a peak in Colorado and a broad
area of high probabilities across the Gulf Coast and Southern Plains states.
However, when a negative ENSO and a positive NAO were coupled,
the tornado frequency peak in Colorado vanished and a strong
localized peak in the lower Mississippi River Valley emerged. Finally, when both ENSO and NAO were in their positive phases,
the peak region of activity was in Oklahoma
and Arkansas.
The analysis was repeated for the F2 to F5 tornado reports
only. Dr. Francis noted that a possible shortcoming in this
analysis stems from the low frequency of reports for these
stronger, rarer, tornado events. Nonetheless, similar
patterns were present in the data for the F2 to F5 tornado
reports. The negative ENSO and positive NAO pattern demonstrated
a shift to the southeast in the location of the peak frequency
of tornadoes, primarily over Alabama, southern Georgia, and
the panhandle of Florida. No other significant deviation
from the analysis for all tornado reports was found for the
rest of the continental United States.
Finally, the analysis of the F4 and F5 tornado paths suggests
that tornado alley may exhibit a “ring of fire” type of phenomenon,
with a peak in distribution stretching from western Iowa southward
to Oklahoma, eastward through Mississippi and Alabama, and
northward into central and southern Indiana. It is not known
at this time whether this is an artifact of the data bias
or reporting issues, inconsistent damage analyses based on
the Fujita Scale, or the result of something as substantive
as elevation changes.
Notes
Compiled by:
Mike
Spinar, Secretary, 2004-2005 and Nancy Westcott, Secretary,
2005-2006.
References
Brooks,
H.E., 1999: Severe thunderstorm climatological probabilities.
<URL:
http://www.nssl.noaa.gov/hazard/>
Concannon, P. R., H. E. Brooks, and C. A. Doswell III, 2000: Climatological
risk of strong and violent tornadoes in the United
States. Preprints, 2nd Symposium on Environmental Applications,
Long Beach, CA, Amer. Meteor. Soc,, 212-219.
Schaefer, J.T., and C. Marzban, 2000: Tornadoes in the United
States as related to the tropical pacific sea surface temperature.
Preprints, 20th Conf. on Severe Local Storms, Orlando,
FL, Amer. Meteor. Soc., 18-121.
Minutes
of the May 24th meeting of the Central Illinois
Chapter of the American Meteorological Society.
The Central Illinois Chapter of the AMS met on May 24, 2005
at Tuscany Steak and Pasta House in Decatur, IL. Approximately 24 people attended
the meeting.
Chris Miller, Warning Coordination Meteorologist, Lincoln
WFO, and outgoing president of the CIAMS, reported:
1)
Considerable
effort was made to update the constitution and by-laws during
the past year and the chapter agreed to the changes at the
last meeting.
2)
The first post-cards
announcement for the planned 2nd Midwest Extreme and Hazardous
Weather Conference sponsored by the Central Illinois Chapter
of the AMS. The conference will be held in Champaign on 14-15 October 2005.
Featured speakers this year will be Dr. Paul Kocin, Tim Marshall,
P.E., and Dr. Morris Weisman. This conference provides
a venue for the presentation of case studies, operational
research, and applied climatological research related to the
extreme and hazardous weather that occurs in the Midwest,
including: tornadoes, severe thunderstorms, snowstorms, ice
storms, floods, lake-effect snowstorms, lake-breeze storms,
cold waves, heat waves, dense fog, and all related human impacts.
Mike Spinar, research meteorologist at the Illinois Sate Water
Survey and chair of the Education and Outreach Committee also
shared several items of note. First, the CIAMS provided
judges for the Illinois Academy of Science’s Central Region
Science Fair at Lincoln Land Community College on March
19th. The committee also provided questions,
as well as judges, for the Illinois State Olympiad Competition
held April 9, 2005 and the National Science Olympiad Competitions
on 19-21 May, both in Champaign, Illinois.
New officers for the period, June 1, 2005 to May 31, 2006
were selected at the meeting:
President: Michael Kruk (mkruk@sws.uiuc.edu)
President-Elect: Tom Bellinger (bellinger@iema.state.il.us)
Secretary: Nancy Westcott (nan@uiuc.edu)
Treasurer: Llyle Barker (llyle.barker@noaa.gov)
Mr. Paul Merzlock, Lead Forecaster at the Romeoville, Illinois National Weather Service Office, presented a talk entitled,
“14 Years Later: A Comparison between the Roanoke
and Plainfield Tornadoes”. The talk detailed a synoptic comparison
between the 28 August 1990 F-5 tornado, which struck the town
of Plainfield, Illinois and the 13 July, 2004 F-4 tornado,
which struck the Parsons Manufacturing Plant near Roanoke,
Illinois. Both powerful tornadoes occurred relatively
late in the tornado season when usually only weaker events
occur, and both events deviated from the traditional conceptual
model of a strong low Convective Available Potential Energy
(CAPE) / high vertical wind shear storm. In contrast
to the typical April or May event, these two late season storms
were associated with over 6000 J/kg of surface-based CAPE and moderate to low shear values. The storms developed rapidly and both
were the only significant tornado produced in Illinois
during each event.
Given that both systems evolved near a weak stationary frontal
boundary, with dewpoint temperatures well into upper 70°s
and lower 80°s Fahrenheit over much of the region, it is not
necessarily surprising that large thunderstorms developed.
Indeed, a derecho later formed from the supercell spawning
the Roanoke storm. What is surprising, however, are
the narrow ¼-mile path widths and the rapid storm initiation
to tornado development (a few tens of minutes) seen with each
system.
In as much as the two storms were very similar in nature,
they illustrate the differences in technology utilized by
the National Weather Service between the early 1990s and the
present day. Chicago meteorologists in 1990 interpreted
Weather Surveillance Radar (WSR) 57 reflectivity images without
the advantage of Doppler velocity information, making it more
difficult to diagnose tornadic low-level rotation. In
addition, forecasters working during the Plainfield event
relied on models, such as the Nested Grid (NGM) and Limited
Fine Mesh (LFM) models, which were better at showing larger
scale synoptic features. In contrast, the forecasters
working in 2004 had an array of mesoscale numerical weather
prediction models, including ETA, MM5, and the Weather Research
and Forecasting (WRF) model at their disposal to assist with
forecasting storm development. Once storm development
was initiated, the WSR 88-D radar was used to diagnose the
actual tornadic debris cloud. This allowed for tailored
warnings that helped save the lives of all the employees of
the Parsons manufacturing plant.
After
questions the meeting adjourned around 9:30 PM.
Mike
Spinar, Secretary, 2004-2005 and Nancy Westcott, Secretary,
2005-2006.
|
