FXUS63 KILX 291743
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1143 AM CST SUN NOV 29 2009

.DISCUSSION...
ISSUED 1013 AM CST SUN NOV 29 2009

COLD FRONT LOCATED EAST OF THE IL RIVER AT 16Z. A LARGE AREA OF
VIRGA AND -RA LOCATED FROM LINCOLN NORTHWARD...AHEAD OF THIS COLD
FRONT. STILL LOOKS LIKE A BETTER CHANCE OF -RA ACROSS EAST CENTRAL
AND SOUTHEAST ILLINOIS THIS AFTERNOON...AS THERE IS MORE MOISTURE
THERE. WL SEND OUT AN UPDATE TO LOWER HIGH TEMPERATURES IN THE
NORTHWEST...THE FRONT HAS ALREADY COME THROUGH AND WITH OVC
SKIES...DONT THINK TEMPERATURES WL WARM MORE THAN A DEGREE OR 2.
FORECAST FOR THE REMAINDER OF THE AREA IS ON TRACK.

&&

.AVIATION...
ISSUED 1136 AM CST SUN NOV 29 2009

COLD FRONT JUST WEST OF INTERSTATE 55 AT 1730Z...CEILINGS JUST
BEHIND THIS FRONT HAVE FALLEN TO 1000 TO 1500 FT. AN AREA OF
CLEARING NOTED ON SAT IMAGERY ACROSS SE IA...HOWEVER ST-CU DECK OF
1500 TO 2000 ACROSS IA MOVING IN BEHIND. THINK THAT THE CLEARING
WL REACH PIA AROUND 21Z...HOWEVER WL ONLY LAST 2 HOURS...AS THIS
ST-CU DECK FILLS IN BEHIND. SHRA SHOWING UP ON RADAR...AND THINK
THE BEST CHANCES ACROSS EASTERN IL...NEAR THE COLD FRONT LATE THIS
AFTERNOON. LOW CLOUDS ERODE TONIGHT IN THE WESTERN TERMINALS...PERSISTING
UNTIL LATE IN THE EAST. MODEL SOUNDINGS HINT AT CU REDEVELOPMENT
MON AFTERNOON.

DPK
&&

.PREV DISCUSSION...
ISSUED 330 AM CST SUN NOV 29 2009

FORECAST CONCERN IS CHANCES OF RAIN TODAY INTO TONIGHT ESPECIALLY
OVER EASTERN IL. THEN ADDRESSING NEXT WEATHER SYSTEM WED/THU AS
COLDER AIR FILTERS INTO IL DURING THE 2ND HALF OF THE WEEK. 00Z
SHORT RANGE MODELS ARE IN FAIR AGREEMENT. BUT MODELS DIVERGE WITH
HANDLING WX SYSTEM WED/THU WITH GFS AND ECMWF TRENDING FURTHER SE
WITH STRONG STORM SYSTEM WED/WED NIGHT AND WHILE GEM AND SREF
MODELS ARE FURTHER NW WITH QPF INTO SE HALF OF IL WED NIGHT. WILL
USE A BLEND BETWEEN THE FURTHER SE GFS/ECMWF AND FURTHER NW
GEM/SREF MODELS FOR WED/THU SYSTEM. 

09Z/3 AM SURFACE MAP SHOWS A COLD FRONT EXTENDING FROM NW IL/MO 
INTO SE KS WITH WEAK 1007 MB LOW PRESSURE IN SE IA AND PRESSING
SLOWLY SE TOWARD GALESBURG. MOSTLY CLEAR SKIES EAST OF THE IL RIVER 
WHILE CLOUDS INCREASING WEST OF THE IL RIVER. MILD TEMPS WERE IN
THE 40S WITH AREAS FROM SPRINGFIELD SW AROUND 50F. ALOFT A 549 DM
500 MB LOW WAS OVER SOUTHERN CA WHILE NORTHERN STREAM TROF OVER
THE DAKOTAS/MN. UPPER LEVEL RIDGE WAS OFF THE WEST COAST AND
ACROSS THE SE STATES.

SHORT TERM...TODAY THROUGH TUESDAY NIGHT.

MODELS LIFT WEAK LOW PRESSURE FROM SE IA NE INTO SE LOWER MI BY
18Z/NOON PULLING THE COLD FRONT SE INTO CENTRAL IL AND TO NEAR
LAWRENCEVILLE BY 00Z/6 PM. JUST A SLIGHT CHANCE OF SHOWERS
DEVELOPING DURING THIS MORNING WITH CHANCES OF SHOWERS INCREASING
THIS AFTERNOON EAST OF I-55 WITH LIKELY CHANCES FROM I-57 EAST.
CHANCES OF RAIN WILL DIMINISH OVER EASTERN IL DURING THIS EVENING
WITH MOST AREAS DRY OVERNIGHT AS THE RAIN SHIFTS SE OF IL WITH THE
COLD FRONT MOVING SE ACROSS KY. WITH SLOWER ARRIVAL OF COLD FRONT
THAN EARLIER EXPECTED...INCREASED HIGHS BY A FEW DEGREES TODAY
INTO THE UPPER 40S NW OF THE IL RIVER TO THE MID 50S IN SE IL. 

UPPER LEVEL TROF THAT MOVES ACROSS IL TONIGHT QUICKLY EXITS EAST
OF IL MON WHILE HIGH PRESSURE OVER THE PACIFIC NW MOVES INTO THE
MID MS VALLEY AND DECREASES CLOUDS OVER CENTRAL/SE IL LATER
TONIGHT INTO MON MORNING WITH MOSTLY SUNNY SKIES BY MON AFTERNOON.
COOLER HIGHS MON IN THE MID TO UPPER 40S WHICH IS CLOSE TO NORMAL
FOR LATE NOV. 

HIGH PRESSURE DRIFTS OVER THE SE STATES TUE WITH RETURN SOUTH FLOW
OF MILDER AIR BACK INTO IL AHEAD OF THE NEXT APPROACHING WX SYSTEM
AND COLD FRONT. HIGHS TUE BACK IN THE LOW TO MID 50S WITH AMPLE
SUNSHINE. 

LONG TERM...WEDNESDAY THROUGH SATURDAY.

EXTENDED MODELS/ENSEMBLES CONTINUE TO SHOW LARGE CUTOFF UPPER
LEVEL LOW IN SOUTHERN CA MOVING EAST ACROSS THE SOUTHERN STATES
INTO MID WEEK KEEPING ITS BEST MOISTURE SOUTH AND EAST OF IL.
NORTHERN STREAM SHORT WAVE TROF DIGS INTO THE MIDWEST AND GREAT
LAKES WED/THU. DOES NOT APPEAR TO PHASE OVER IL SO BEST CHANCES OF
PRECIPITATION LOOKS TO STAY SOUTH AND EAST OF IL. HAVE CHANCE OF
LIGHT RAIN/SNOW MAINLY SE HALF WED AFTERNOON/WED NIGHT AND JUST
SLIGHT CHANCES OF LIGHT SNOW SHOWERS THU WITH UPPER LEVEL TROF
NEARBY. COLDER AIR TO USHER IN WITH HIGHS WED IN THE LOW TO MID
40S. THEN IN THE MID TO UPPER 30S THU-SAT WITH SE IL NEAR 40F.

HUETTL

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$