Damaging Wind in Illinois, April 11, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
255 PM CDT WED APR 11 2001

FORECAST CONCERNS THIS PD INCLUDE TIMING OF CONVECTION ACRS CWFA THIS
EVENING WITH AREA TO BE COVERED BY WIND ADVSY TNT INTO THU MRNG. LONGER
TERM CONCERNS INCLUDE PRECIP CHANCES LT FRI INTO SAT AND AGAIN ON
EASTER SUNDAY.

WATER VAPOR LOOP SHOWING IMPRESSIVE DRY SURGE STREAKING EWD THRU CNTRL
MO THIS AFTN WITH MOST INTENSE CONVECTION OCCURRING NORTH-NORTHEAST OF
H5 CLOSED LOW. BASED ON CONTINUITY...IT APPEARS MID LVL DRY SLOT WL
PUSH EAST OF A PIA TO SPI LINE BY 830 THIS EVENING...AND THRU THE
REMAINDER OF THE CWFA BY 1130 PM. LAPS HOURLY SOUNDING DATA ACRS
NE MO INDICATING LOW LVL WINDS BACKING AHD OF APPRCHG SHORTWAVE WHICH
SHOULD AID IN SEVERE THREAT INTO THIS EVENING. 0-6KM SHEAR AROUND
60 KTS SO PLENTY OF SHEAR AVAILABLE TO ANY STORMS THAT DO DEVELOP
AHEAD OF THE APPRCHG FRONT. ONLY PROBLEM IS THAT LATEST LIGHTNING
DATA SUGGESTS MOST OF THE STRIKES SHIFTING NORTH...CLOSER TO SFC AND
UPPER LOW WHICH HAPPENED WITH THE LAST MAJOR WAVE THAT PULLED WELL
WEST OF OUR CWA LAST WEEK.

CONVECTION SHOULD END FROM WEST TO EAST IN THE 01-07Z TIME FRAME THIS
EVENING WITH WINDS A CONCERN LT TNT INTO THU MRNG. MESOETA MODEL INDICATING
50KTS JUST OFF THE DECK TNT INTO THU MRNG IN ALL BUT THE SERN
COUNTIES. SHOULD SEE THE WINDS SUBSIDE BY TOMORROW AFTN AS INTENSE
SFC LOW PULLS NORTH OF LK SUPERIOR. RELATIVELY QUIET WX PATTERN INTO FRIDAY
AS HIGH PRESSURE MOVES IN FROM THE PLAINS WITH SHORTWAVE ENERGY
FORECAST TO MOVE ACRS THE MIDWEST FRIDAY. LOW AND MID LVL MOISTURE
LACKING WITH THIS SHORTWAVE...HOWEVER...A MORE SIGNIFICANT WAVE DEVELOPS
ACRS THE PLAINS FRIDAY AFTERNOON AND SHIFTS INTO THE CWA FRIDAY
NIGHT. WL INTRODUCE 30 POPS FRIDAY NIGHT AS MOISTURE MAY BE A BIT
MORE PLENTIFUL WITH THIS SYSTEM.

UPPER PATTERN FLATTENS OUT ACRS THE MIDWEST AS MEDIUM RANGE MODELS SUGGEST
LNGWV TROF TO REFORM ACRS THE LAKES REGION AGAIN BY EARLY NEXT WEEK WHICH
SHOULD BRING MORE NORMAL EARLY APRIL WX TO THE MIDWEST.

...PRELIMINARY NUMBERS FOR COORDINATION ONLY...

SPI BB 052/067 042/065 044 44500
PIA BB 050/065 040/062 041 44600
DEC BB 052/067 042/065 044 44500
CMI BB 053/065 042/065 043 44610
MTO BB 055/068 045/068 047 44611
LWV BB 058/072 049/070 050 44610

.ILX...WIND ADVISORY TNT INTO THU MORNING...ROUGHLY ALONG AND NORTH
OF INTERSTATE 70.

SMITH

ILZ027>031-036>038-040>057-061>063-066>068-071>073-111830-

HAZARDOUS WEATHER OUTLOOK FOR CENTRAL ILLINOIS
NATIONAL WEATHER SERVICE LINCOLN IL
1124 AM CDT WED APR 11 2001

THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND THIS EVENING TO THE WEST OF A LINE FROM BLOOMINGTON/NORMAL TO
DECATUR TO TAYLORVILLE. TO THE EAST OF THIS LINE...THERE IS A
MODERATE RISK OF SEVERE THUNDERSTORMS FOR THE REST OF CENTRAL AND
SOUTHEAST ILLINOIS.

A STRONG STORM SYSTEM MOVING INTO THE PLAINS WILL MOVE RAPIDLY ACROSS
IOWA INTO WISCONSIN BY TONIGHT. STRONG SOUTH WINDS WILL TRANSPORT
MOIST AND UNSTABLE AIR INTO THE MISSISSIPPI VALLEY AHEAD OF THE STORM
SYSTEM. SHOWERS AND THUNDERSTORMS WILL REDEVELOP IN THIS UNSTABLE BY
THIS AFTERNOON.

DURING THE AFTERNOON...THUNDERSTORMS WILL REDEVELOP OVER CENTRAL
MISSOURI AND CENTRAL IOWA...AND MOVE RAPIDLY INTO CENTRAL
ILLINOIS. THE MOST LIKELY TIME FRAME FOR SEVERE WEATHER OVER THE AREA
IS FROM LATE AFTERNOON UNTIL MIDNIGHT. TORNADOES WILL BE POSSIBLE
IN THE HIGH RISK AREA...BUT THE PRIMARY SEVERE WEATHER THREAT IS
EXPECTED TO BE DAMAGING WINDS AND LARGE HAIL.

EMERGENCY MANAGERS AND STORM SPOTTER GROUPS SHOULD KEEP ABREAST OF
THE LATEST WEATHER FORECASTS AND BE PREPARED FOR ACTIVATION
THIS AFTERNOON AND THIS EVENING.

KETCHAM