Flash Flooding and Damaging Winds in Illinois, January 12 to 13, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
900 PM CST WED JAN 12 2005

.DISCUSSION...CURRENT ZONES/GRIDS IN GOOD SHAPE SO WL HOLD OFF ANY
UPDATES UNTIL SPC DECIDES WHAT TO DO WITH CURRENT WATCH AND IF THEY
WILL BE EXTENDING ANY BOXES EAST AND SOUTH. NOT GETTING ANY SVR
REPORTS FROM STORMS ACRS OUR SW AND WEST THIS EVENING. LATEST LAPS
SOUNDING SHOWING FAIRLY SIG STABLE LAYER FROM 950-850 MB WHICH
MAY BE PREVENTING MUCH OF THE DOWNWARD MOMENTUM TRANSFER FROM THE
STRONGER STORMS TO BE REACHING THE SURFACE. 700-500 MB PROFILER
WINDS HAVE BACKED INTO A MORE SOUTHERLY DIRECTION IN RESPONSE TO THE
SRN STREAM SHORTWAVE NOW TAKING ON A MORE NEGATIVE TILT AS IT EJECTS
SLOWLY TO THE EAST THIS EVENING. FAIRLY EXPANSIVE WARM CONVEYOR BELT
SEEN ON IR SATELLITE LOOP FROM ERN TX NWD TO SRN WISCONSIN NOT MAKING
MUCH PROGRESS TO THE EAST...SUGGESTING AREAS THAT HAVE ALREADY SEEN
HEAVY RAINFALL WL SEE ADDL MODERATE TO HEAVY RAINS OVERNIGHT. BAND
OF RAIN AND THUNDERSTORMS SHOULD SHIFT EAST TOWARDS ERN IL LATE TNT
INTO THU MORNING BRING THE THREAT FOR HEAVY RAINS TO THAT AREA.

NO CHANGES MADE TO CURRENT FLOOD WATCH AND WIND ADVISORY.

&&

.PREV DISCUSSION...MAIN FORECAST ISSUE IN THE SHORT TERM CONTINUES
TO THE BE AMOUNT OF RAIN POSSIBLE TONIGHT. BEYOND TONIGHT...QUIET
AND VERY COLD WEATHER TO PREVAIL OVER THE REGION.

SHORT TERM...TONIGHT THROUGH SATURDAY...
12Z ETA AND GFS ARE VERY SIMILAR IN TIMING OF THE FRONTAL BOUNDARY
THROUGH THE STATE TONIGHT...THOUGH 18Z ETA SLOWED DOWN THE SPEED OF
THE FRONT A LITTLE. WILL GO WITH A BLEND OF THE TWO MODELS.

FOR TONIGHT...PWS ARE IN EXCESS OF AN INCH...WITH TREMENDOUS LIFT
ASSOCIATED WITH THE FRONTAL PASSAGE...SO SHOULD SEE QPF AMOUNTS
BETWEEN 1 AND 2 INCHES OVER THE ENTIRE CWA. FLOOD WATCH TO REMAIN IN
EFFECT FOR TONIGHT FOR ALL OF THE CWA. ALSO...LI/S NEAR ZERO OVER
AREA THIS EVENING AS WELL AS STEEP LAPSE RATES. HOWEVER... STRONG
INVERSION TO REMAIN IN CONTROL OF A LARGE PORTION OF THE
CWA...DESPITE WARM SFC TEMPS. SO ANY SEVERE WOULD BE ISOLATED IN
NATURE. SPC HAS REMOVED ALL OF CWA OUT OF SLIGHT RISK FOR TONIGHT.

ON ANOTHER NOTE...STRONG WINDS ALOFT ARE BEGINNING TO MIX DOWN FOR
OUR SOUTHEASTERN COUNTIES AS INVERSION HAS WEAKENED IN THIS AREA. SO
WILL SEE WINDS INCREASE TONIGHT...WITH GUSTS TO NEAR 45 MPH. WILL
ISSUE A WIND ADVISORY FOR AREAS ALONG AND SOUTH OF I-70 FROM 6 PM TO
4 AM.

INITIALLY THERE WAS SOME CONCERN ABOUT A MIX OF RAIN AND SNOW...
CHANGING TO ALL SNOW IN OUR NORTHERN COUNTIES TONIGHT. COLD AIR WILL
BE SLOW TO FILTER INTO THE REGION...AS 850 TEMPS REMAIN ABOVE ZERO
THROUGH 12Z...SO BACKED OFF ON MENTION OF MIXED PCPN...EXCEPT FOR
AREAS ALONG AND NORTHWEST OF THE ILLINOIS RIVER AFTER 09Z.

PCPN TO COME TO AN END ON THURSDAY AS FRONT EXITS CWA BY 15Z...
TAKING ALL OF THE MOISTURE AND LIFT WITH IT. LITTLE OR NO
ACCUMULATION IS EXPECTED BEFORE THE SNOW COMES TO AN END AROUND
NOON...FOR AREAS ALONG AND WEST OF I-57. EAST OF I-57...SHOULD ONLY
SEE RAIN BEFORE ENDING AROUND NOON AS WELL. OTHERWISE...JUST EXPECT
FALLING TEMPS THROUGHOUT THE DAY.

BITTERLY COLD WEATHER TO PREVAIL THURSDAY NIGHT THROUGH
SATURDAY...WITH DAYTIME HIGHS IN THE TEENS AND LOWER 20S AND
OVERNIGHT LOWS IN THE SINGLE DIGITS.

LONG TERM...SATURDAY NIGHT THROUGH TUESDAY...
FOR THE EXTENDED PERIOD...NO MAJOR CHANGES MADE AS HIGH PRESSURE
BUILDS IN THE REGION. DID KEEP MENTION OF A CHANCE OF LIGHT SNOW
SUNDAY AND ADDED MENTION FOR SUNDAY NIGHT AS SYSTEM UNDER CUTS THE
HIGH. OTHERWISE...TEMPS TO SLOWLY MODERATE FOR THE BEGINNING OF THE
WORK WEEK.
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH FOR ENTIRE FORECAST AREA TONIGHT. WIND ADVISORY FOR
AREAS ALONG AND SOUTH OF I-70 FROM 6 PM TONIGHT TO 4 AM THURSDAY
MORNING.
&&

SMITH/BYRD

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE LINCOLN IL
1055 AM CST WED JAN 12 2005

ILZ027>031-036>038-040>057-061>063-066>068-071>073-131200-
CASS-CHAMPAIGN-CHRISTIAN-CLARK-CLAY-COLES-CRAWFORD-CUMBERLAND-
DE WITT-DOUGLAS-EDGAR-EFFINGHAM-FULTON-JASPER-KNOX-LAWRENCE-LOGAN-
MACON-MARSHALL-MASON-MCLEAN-MENARD-MORGAN-MOULTRIE-PEORIA-PIATT-
RICHLAND-SANGAMON-SCHUYLER-SCOTT-SHELBY-STARK-TAZEWELL-VERMILION-
WOODFORD-
INCLUDING THE CITIES OF...BLOOMINGTON...CHAMPAIGN...DANVILLE...
DECATUR...EFFINGHAM...FLORA...GALESBURG...HAVANA...JACKSONVILLE...
LAWRENCEVILLE...LINCOLN...MATTOON...PEORIA...SHELBYVILLE...
SPRINGFIELD AND TAYLORVILLE
1055 AM CST WED JAN 12 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND SOUTHEAST ILLINOIS.

.DAY ONE...TODAY AND TONIGHT...
HEAVY RAINFALL AND POTENTIAL FLOODING IS THE MOST SIGNIFICANT THREAT
TONIGHT. SCATTERED THUNDERSTORMS WILL BE POSSIBLE BY LATE AFTERNOON
ACROSS CENTRAL AND SOUTHEAST ILLINOIS.  MORE WIDESPREAD THUNDERSTORMS
ARE EXPECTED TO IMPACT THE AREA WEST OF THE ILLINOIS RIVER BY MIDDLE
EVENING AND THEN SWEEP EASTWARD ACROSS ILLINOIS AHEAD OF A STRONG
COLD FRONT.  ABUNDANT MOISTURE IS STREAMING NORTHWARD TODAY AHEAD OF
THIS BOUNDARY. RAINFALL AMOUNTS OF ONE TO TWO INCHES WITH LOCALLY
HIGHER AMOUNTS WILL BE POSSIBLE.  THIS HEAVY RAINFALL FALLING ON
ALREADY SATURATED GROUND WILL LIKELY LEAD TO ANOTHER ROUND OF
FLOODING.  CREEKS AND RIVERS ACROSS THE REGION REMAIN AT OR ABOVE
BANKFULL AND THIS ADDITIONAL RAIN WILL ONLY ADD TO THE FLOW.

IN ADDITION...SOME OF THE STRONGER STORMS WILL BE CAPABLE OF
PRODUCING WIND GUSTS TO 50 MPH...AND SMALL HAIL.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

VERY COLD AIR WILL FILTER INTO THE REGION THURSDAY AND INTO THE
WEEKEND.  TEMPERATURES FALLING INTO THE SINGLE DIGITS COMBINED WITH
NORTHWEST WINDS OF 10 TO 20 MPH WILL PRODUCE WINDCHILLS BELOW ZERO
THURSDAY NIGHT AND FRIDAY MORNING NORTH OF INTERSTATE 72.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

&&
THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC AND CLIMATE
INFORMATION...IS AVAILABLE ON THE WEB AT:

HTTP://WWW.CRH.NOAA.GOV/ILX. THIS ADDRESS IS ALL IN LOWER CASE.

BARKER