Damaging Wind in Illinois, March 9, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
200 AM CST SAT MAR 9 2002

MAIN CONCERN THIS FORECAST PERIOD IS TIMING OF STRONG COLD FRONT AND
ENDING OF STRONG TO POSSIBLY SEVERE CONVECTION THIS MORNING...STRONG
GRADIENT WINDS AND WIND ADVISORY TODAY...AND HOW MUCH COLDER IT WILL
GET THIS WEEKEND. MODELS IN EXCELLENT AGREEMENT AS ETA HAS SLOWED
DOWN A BIT FROM YESTERDAY AND CLOSER TO AVN.

07Z SURFACE ANALYSIS HAS 996 MB LOW JUST SW OF WATERLOO IA KALO WITH
ATTENDANT SHARP COLD FRONT EAST OF I-35 OVER NW MO AND EAST OK.
WIDESPREAD CONVECTION IN WARM SECTOR ACROSS IL RACING NE AT 50 MPH.
SEVERE SQUALL LINE WITH FRONT RACING EAST TOWARD KDVN AND KUIN.
SOUTH WINDS 18 TO 28 MPH AND GUSTS 28 TO 44 MPH APPROACHING WIND
ADVISORY CRITERIA. KBMI WIND GUST OF 52 MPH AT 2 AM. AFTER FRI
AFTERNOON HIGHS AROUND 70...UNSEASONABLY MILD TEMPS AT 1 AM IN THE
UPPER 50S AND LOWER 60S...WHILE DEWPOINTS 45 TO 55.

MODELS BRING COLD FRONT INTO WESTERN CWA BY 12Z...TO I-57 BY 15Z AND
JUST EAST OF IL/IN BORDER BY 18Z. SQUALL LINE SHOULD WEAKEN SOMEWHAT
WITH LESS INSTABILITY EAST OF THE MS RIVER THIS MORNING AS IT RACES
EAST ACROSS IL THRU 15Z. BUT PRESSURE GRADIENT INCREASING WITH LOW
DEEPENING TO UPPER MI AND 45-55 KNOTS 925-850 MB WINDS COULD BE
ADVECTED TOWARD SURFACE WITH THIS LINE OF CONVECTION. SEVERE
THUNDERSTORM WATCH WEST OF I-55 EXPIRES AT 4 AM. MAINTAINING WIND
ADVISORY TODAY ACROSS CWA AS SOUTH WINDS INCREASE AND TURN WEST AT
25 TO 35 MPH THRU 6 PM WITH GUSTS TO 50 MPH OR HIGHER WITH LINE OF
STORMS INTO MID MORNING. CONVECTION ENDS BY NOON WITH 12Z-18Z QPF
RANGING FROM TENTH INCH WEST...QUARTER INCH ALONG I-57 AND HALF INCH
ALONG IL/IN BORDER AND NGM/ETA/AVN SIMILAR ON THIS. TEMPS IN THE 50S
AT SUNRISE/12Z TUMBLE INTO THE UPPER 20S NW AND TO NEAR 35 SE BY
SUNSET/00Z.

NEGATIVE TILTED SYSTEM DEEPENS AND QUICKLY LIFTS NE INTO EASTERN
CANADA TONIGHT AS 1040 MB HIGH SETTLES INTO THE SOUTHERN PLAINS
STATES FROM THE ROCKIES. SKIES CLEAR LATE THIS AFTERNOON AND EARLY
EVENING WITH WINDS DIMINISHING TO 10 TO 15 MPH LATE TONIGHT. MAV
LOWS AROUND 20 OK WITH 20 TO 25 SE THOUGH OTHER GUID NUMBERS NOT
MUCH COLDER. MOSTLY SUNNY SUNDAY WITH HIGHS A FEW DEGREES BELOW
NORMAL IN THE 40S. WILL LOWER HIGHS SE GROUP DOWN A CATEGORY.

PROGRESSIVE FLOW EARLY NEXT WEEK WITH A MUCH WEAKER SYSTEM RACING
EAST INTO THE MIDWEST MON AND MON NIGHT. AVN QUICKER BRINGING TENTH
TO QUARTER INCH QPF INTO IL MON AFTERNOON AND NIGHT AND DRY DURING
THE DAY TUE...WHILE ETA WAITS UNTIL MON EVENING. WILL LEAVE CURRENT
FORECAST ALONE WITH NEXT CHANCE OF SHOWERS MON NIGHT.

PRELIMINARY CCF FOR COORDINATION PURPOSES...

SPI WU 050/021 047/029 051 07700
PIA WU 050/020 044/028 049 07700
DEC WU 053/021 045/027 051 07800
CMI WU 055/021 042/025 049 07900
MTO WU 055/023 044/027 051 07900
LWV WU 059/025 048/028 054 07+00

.ILX...WIND ADVISORY ENTIRE CWA TODAY.

KH