FXUS63 KILX 241645
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1045 AM CST THU DEC 24 2009
.DISCUSSION...
ISSUED 1035 AM CST THU DEC 24 2009
MOST OF THE RAIN HAS BEEN EAST OF I-55 THIS MORNING CURRENTLY
EXTENDING ALONG AND SE OF A BLOOMINGTON TO ALTON LINE. BUT RAIN WILL
SPREAD NORTHWARD FROM SE MO/SW IL ACROSS AREAS FROM I-55 WEST DURING
THE AFTERNOON AND CONTINUE TONIGHT. BETWEEN 1 AND 2 INCHES OF
ADDITIONAL RAINFALL IS EXPECTED TODAY AND TONIGHT WITH ISOLATED
THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING. WILL CONTINUE
THE FLOOD WATCH THROUGH THIS EVENING ACROSS CENTRAL/SE IL AND MAY
NEED TO BE EXTENDED THROUGH TONIGHT UNTIL DAWN FRI ESPECIALLY IN
NORTHERN AND EASTERN AREAS. WILL BE WINDY TOO TODAY AND TONIGHT
WITH ESE WINDS 15 TO 25 MPH AND GUSTS OF 25 TO 40 MPH...AND THINK
WINDS WILL STAY BELOW WIND ADVISORY CRITERIA.
16Z/10 AM SURFACE MAP SHOWS 995 MB LOW PRESSURE DEEPENING ALONG
THE TX/OK/AR BORDER WITH A FRONTAL BOUNDARY EXTENDING NORTHWARD
ACROSS CENTRAL MO/IA/MN. A PSEUDO WARM FRONT WAS SOUTH OF IL FROM
CENTRAL KY INTO CENTRAL AR. TEMPS WERE 35 TO 40F FROM I-74 NORTH
AND 40 TO 45F SOUTH OF I-74. ALOFT A STRONG 538 DM 500 MB LOW WAS
NEAR DALLAS TEXAS WHILE 532 DM 500 MB LOW WAS ALONG THE MT/ND BORDER.
MODELS LIFT LOW PRESSURE NNE TO NORTH CENTRAL AR BY SUNSET AND TO
THE IA/MO/IL BORDER BY SUNRISE FRI AS IT DEEPENS TO 988 MB. STRONG
DYNAMIC LIFT AHEAD OF THIS DEEPEN STORM WILL BRING WIDESPREAD
RAINS NORTHWARD ACROSS CENTRAL IL THIS AFTERNOON AND CONTINUE
TONIGHT. EASTERN IL EAST OF I-55 HAS ALREADY SEEN WIDESPREAD
SHOWERS THIS MORNING ALONG WITH LOCALLY HEAVY RAINS. HIGHS TODAY
WILL RANGE FROM THE LOWER 40S FROM I-74 NORTH TO THE UPPER 40S TO
NEAR 50F FROM SPRINGFIELD TO TERRE HAUTE SOUTH.
HUETTL
&&
.AVIATION...
ISSUED 537 AM CST THU DEC 24 2009...FOR THE 12Z TAFS
LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. IFR VIS AND CIGS
AND RAIN WILL PREVAIL FOR MUCH OF THE TIME. PERIODS OF MVFR CIGS
THIS MORNING SHOULD LOWER TO STEADY IFR CIGS BY 16Z AND REMAIN
THERE THROUGH AT LEAST MIDNIGHT TONIGHT.
AS DRY AIR ALOFT INVADES LATER TONIGHT...PRECIP WILL DIMINISH TO
DRIZZLE. COLD AIR IS NOT EXPECTED TO ARRIVE AT ANY TAF SITES UNTIL
AFTER 12Z CHRISTMAS MORNING.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 315 AM CST THU DEC 24 2009
WARM AIR PUSHING INTO SRN IL THIS MORNING AS PRECIP SPREADS AND
SFC LOW DEVELOPS OVER WRN GULF COAST. VERY LITTLE IN THE WAY OF
CHANGE FOR THE FORECAST AS THE MODELS COME INTO AGREEMENT ABOUT
THE HANDLING OF THIS SYSTEM. PLENTY OF LOW AND MID LEVEL WARM
ADVECTION IN ADVANCE OF THE LOW MOVING ALMOST DUE NORTH UP THE
MISS RIVER VALLEY WILL RESULT IN PLENTY OF RAIN FOR THE
REGION...AND THE WINTRY WEATHER WILL BE CONFINED TO THE UPPER
MIDWEST AT LEAST THROUGH CHRISTMAS EVE. USING THE NAM IN THE SHORT
TERM.
SHORT TERM...TODAY AND TOMORROW...
BLUSTERY WINDS AND RAIN BECOMING MORE WIDESPREAD FROM THE SHOWERS
OF THIS MORNING...AND WITH THE RATHER DYNAMIC SYSTEM ON
APPROACH...ISLD THUNDER STILL A GOOD CHANCE IN THE SRN CWA...FOR
TONIGHT AND THIS EVENING. MAIN THREAT WITH THIS SYSTEM
HOWEVER...IS FLOODING. MANY LOCATIONS IN CENTRAL ILLINOIS ALREADY
RECD AN INCH OR SO OF LIQUID...AND THE PRECIP IS JUST BECOMING
MORE EFFICIENT AS A MOISTURE STREAMS INTO THE REGION FROM THE GULF
COAST. FLOOD WATCH CONTINUES UNTIL MIDNIGHT TONIGHT. IN THE EARLY
MORNING HOURS OF FRIDAY...WILL START TO SEE THE TEMPERATURES DROP
A BIT ON THE BACKSIDE OF THE LOW AS IT OCCLUDES AND THE PRECIP
BEGINS TO SWITCH OVER TO SNOW. CWA SHOULD BECOME SNOW DOMINATED BY
FRI AFTERNOON...THOUGH AT THIS POINT THE HEAVIEST OF THE PRECIP
WILL HAVE SUBSIDED...LEAVING LITTLE MORE THAN A DUSTING FOR AREAS
SOUTH OF INTERSTATE 70...AND ONLY UP TO AN INCH IN THE FAR NRN
PORTIONS OF CWA.
LONG TERM...SATURDAY THROUGH MONDAY...
LIGHT SNOW CONTINUES THROUGH SATURDAY...AS THE LOW MEANDERS A BIT
IN THE NORTH AND CENTRAL PORTIONS OF THE STATE. WHEREAS THE SNOWFALL
LIKELY TO BE MORE SHOWERY ON THE SOUTH SIDE OF THE LOW...BEING
RELATIVELY CONSISTENT THROUGH THE DAY AND EVENING COULD END UP
SEEING UP TO INCH OR SO FOR THE MAJORITY OF THE CWA. LOW BEGINS TO
MOVE OUT ON SUNDAY AND WILL SEE A RETURN OF FRIGID TEMPS AS THE
HIGHS FOR SUN AND MON REMAIN IN THE 20S...WITH LOWS IN THE LOW TO
MID TEENS.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH THIS EVENING FOR ILZ027>031-036>038-040>057-
061>063-066>068-071>073.
&&
$$
