Hail and Damaging Winds in Illinois, November 5 to 6, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
200 PM CST SAT NOV 5 2005

.DISCUSSION...
MAIN CONCERN THIS FCST PACKAGE WITH SEVERE POTENTIAL THIS EVENING
AND THEN WITH NEXT SIGNIFICANT SHORTWAVE AND FRONTAL PASSAGE MID
WEEK. MODELS SIMILAR NOW WITH THIS EVENINGS SYSTEM AS IT TRACKS
QUICKLY ACRS THE MID-MISSISSIPPI VALLEY. SOME MODEL DIFFERENCES
SEEN WITH THE SYSTEM APPROACHING THE STATE LATE TUESDAY AND
WED...ESPECIALLY WITH THE WARM ADVECTION PRECIP THREAT DEPICTED FOR
LATE MONDAY NIGHT AND TUESDAY OVER OUR NORTHERN COUNTIES. FOR NOW...
WL TEND TO SIDE MORE WITH THE GFS AS IT HAS SHOWN GOOD CONSISTENCY
WITH THIS SYSTEM.

SHORT TERM...TONIGHT THROUGH TUESDAY...
LATEST SFC ANALYIS INDICATING LOW PRESSURE OVER SE KANSAS WITH A
WARM FRONT STRETCHING FROM THE LOW INTO NRN MO AND AT OR JUST NORTH
OF GALESBURG AND LACON. SCATTERED THUNDERSTORMS DEVELOPED IN THE
STRONG WARM ADVECTION ZONE WHICH STRETCHED FROM NE OKLAHOMA INTO
CNTRL MO AND SW IL THIS MORNING. AS MAIN SHORTWAVE ENERGY DROPS INTO
KS THIS AFTN...SFC PRESSURE FALLS WILL CONTINUE OVER THE REGION
ALLOWING THE BOUNDARY TO SHIFT FURTHER NORTH INTO NRN IL BY LATE
AFTN. FOCUS THEN SHIFTS TO THE WEST WHERE STORMS SHOULD FIRE LATE
THIS AFTN OR EVENING AS CAP WEAKENS AHEAD OF STRONG SPEED MAX AND
700-500 MB COLD ADVECTION. U OF I MESOSCALE MODEL SUGGESTING THAT
THE TIME FRAME FROM 22Z-01Z THERE SHOULD BE A SIGNIFICANT INCREASE
IN CONVECTON ACRS THE FCST AREA. BASED ON THE UPSTREAM SOUNDING
AT SGF...WONDER IF THAT MAY BE TOO QUICK. ALL THE FCST SOUNDINGS
SUGGEST THAT THE PRIMARY THREAT WOULD BE WITH STRAIGHT LINE WIND
DAMAGE THIS EVENING...HOWEVER IF CELLS CAN BREAK THRU THE CAP
EARLIER THAN EXPECTED...SOME DISCRETE SUPERCELLS WILL BE POSSIBLE
OUT AHEAD OF THE MAIN LINE...WHICH COULD POSE A THREAT FOR NOT ONLY
LARGE HAIL...BUT FOR AN ISOLATED TORNADO. CONVECTIVE LINE SHOULD
SWEEP THROUGH OUR FCST AREA QUICKLY THIS EVENING AND PROBABLY BE
EAST OF THE STATE BY 09Z. AFTER THAT...THE CONCERN WILL BE WITH THE
DEEPENING LOW TO OUR NORTH AND GRADIENT WINDS ACRS OUR AREA THRU
SUNDAY MORNING. WILL BE CLOSE TO ADVSY CRITERIA LATE TONIGHT AND
SUNDAY MORNING...BUT WITH SYSTEM MOVING SO QUICKLY AWAY FROM OUR
AREA AND AFTR COLLABORATION WITH SURROUNDING OFFICES TO THE NORTH
AND EAST...HAVE DECIDED TO HOLD OFF ANY HEADLINES.

QUIET WX RETURNS TO CNTRL IL FOR SUNDAY AS HIGH PRESSURE SETTLES IN
FOR ABOUT A 24 TO 36 HOUR PERIOD. BEST COLD ADVECTION BEHIND
DEPARTING LOW WILL BE TO OUR NORTH AND EAST...AND WITH ANY WRAP AROUND
CLOUDS PUSHING AWAY FROM OUR AREA DURING THE AFTN...WE SHOULD SEE TEMPS
CLIMB TO THE UPPER 50S TO LOWER 60S...OR CLOSE TO GUIDANCE. AS HIGH
PUSHES TO OUR EAST MONDAY AFTN AND EVENING...RETURN FLOW ALREADY SETTING
UP AND CONCERN FOR WARM ADVECTION PRECIP LATE MONDAY NIGHT OR
TUESDAY. MODELS HAVE BEEN HINTING AT THIS FOR A COUPLE OF DAYS NOW
AND MAY ADD SOME SLGT CHANCES AFTR MIDNIGHT MONDAY NIGHT AND INTO
THE DAYLIGHT HOURS OF TUESDAY. TEMPERATURES SHOULD REBOUND QUICKLY BY
TUESDAY WITH 850 TEMPS BACK TO AROUND +12C SUPPORTING AFTN HIGHS
BACK INTO AT LEAST THE LOWER 70S.

LONG TERM...WEDNESDAY THROUGH SATURDAY...
ENSEMBLES SHOWING QUITE A BIT OF SPREAD FOR THE SECOND HALF OF THE
FCST PERIOD WITH THE SHORTWAVE FCST TO DEEPEN IN TO OUR EAST...WHICH
WOULD BRING QUITE A BIT COLDER AIR INTO THE AREA FOR THE END OF THE
WEEK AND WEEKEND. WHERE THE MODELS ARE SHOWING SOME CONSISTENCY
IS ACRS THE PACIFIC NORTHWEST WHERE A STRONG WESTERLY FLOW IS FCST
TO CONTINUE...WHICH WOULD TRANSLATE TO A MORE PROGRESSIVE TROF ACRS THE
ERN US...AND NOT AS MUCH COLD AIR INTRUSION INTO OUR AREA. FOR NOW...WL
HOLD THE FORT WITH COOLER TEMPERATURES BEHIND THE MIDWEEK SYSTEM AND
NOT GET TOO AGRESSIVE WITH ANY COOL OFF FOR THE END OF THE WEEK.
STILL SOME UNCERTAINTY WITH THE PROGRESS OF THE MIDWEEK COLD FRONT WHICH
SOME MODELS SUGGEST MAY GET HUNG UP ACRS THE OHIO VALLEY AS IT BECOMES
PARALLEL TO THE UPPER FLOW. THIS WOULD LEAD TO RAIN CHANCES ACRS OUR
AREA EXTENDING THRU WED INTO THU. FOR NOW...WL LET A FEW MORE MODEL
RUNS IRON OUT THIS DIFFERENCE BEFORE MAKING ANY WHOLE-SALE CHANGES
IN THE DAY 5 AND 6 FORECAST.

&&

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
IL...NONE.

&&

SMITH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
1115 AM CST SAT NOV 5 2005

ILZ027>031-036>038-040>057-061>063-066>068-071>073-061200-
KNOX-STARK-PEORIA-MARSHALL-WOODFORD-FULTON-TAZEWELL-MCLEAN-
SCHUYLER-MASON-LOGAN-DE WITT-PIATT-CHAMPAIGN-VERMILION-CASS-
MENARD-SCOTT-MORGAN-SANGAMON-CHRISTIAN-MACON-MOULTRIE-DOUGLAS-
COLES-EDGAR-SHELBY-CUMBERLAND-CLARK-EFFINGHAM-JASPER-CRAWFORD-
CLAY-RICHLAND-LAWRENCE-
1115 AM CST SAT NOV 5 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
ILLINOIS...EAST CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THERE IS A SLIGHT CHANCE OF SEVERE THUNDERSTORMS ACROSS THE AREA
LATER THIS AFTERNOON AND EVENING. ISOLATED THUNDERSTORMS ARE
EXPECTED TO BECOME MORE NUMEROUS BY THIS EVENING. SOME OF THE
STORMS MAY BECOME SEVERE...WITH THE PRIMARY SEVERE WEATHER THREAT
BEING LARGE HAIL AND DAMAGING WIND GUSTS FROM 5 PM TO MIDNIGHT.
THERE IS ALSO A RISK OF ISOLATED TORNADOES SOUTHEAST OF THE ILLINOIS
RIVER. A COLD FRONT WILL THEN PUSH EAST ACROSS ILLINOIS TONIGHT...
ENDING THE THREAT FOR THUNDERSTORMS FROM WEST TO EAST BY 3 AM.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED LATE THIS AFTERNOON AND EVENING.

KMH