FXUS63 KILX 301730
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1130 AM CST MON NOV 30 2009

.DISCUSSION...
ISSUED 1028 AM CST MON NOV 30 2009

A HIGH PRESSURE RIDGE ACROSS CENTRAL IL AT 16Z. ST-CU DECK ERODING
FROM WEST TO EAST ACROSS THE FORECAST AREA...BY 16Z...WESTERN EDGE
OF CLOUD DECK WAS ROUGHLY I-55. HOWEVER...SOME CU DEVELOPING TO THE WEST OF
THIS CLOUD DECK. WL GO WITH MOSTLY SUNNY ACROSS THE CENTRAL AND
WEST TODAY. TEMPERATURE TRENDS ARE ON TRACK. WL SEND OUT AN UPDATE
SHORTLY FOR SKY TRENDS.

&&

.AVIATION...
ISSUED 1102 AM CST MON NOV 30 2009

ST-CU DECK MOVING ACROSS EAST CENTRAL AND SOUTHEAST ILLINOIS THIS
MORNING. MAIN DECK PAST PIA AND SPI BY 17Z...HOWEVER SOME CU
POPPING UP BEHIND THIS DECK AT PIA. THINK THIS DECK WL CONTINUE TO
SLOWLY ERODE...HOWEVER SCT-BKN CU LINGERING AT PIA...BMI AND DEC.
ONCE SKIES CLEAR...ONLY A FEW CI OVERNIGHT...AND SKC ON TUES.

DPK
&&

.PREV DISCUSSION...
ISSUED 330 AM CST MON NOV 30 2009

FORECAST CONCERN IS ADDRESSING NEXT STORM SYSTEM MOVING ACROSS THE
SOUTHERN AND EASTERN PART OF THE COUNTRY WED/WED NIGHT AND HOW FAR
PRECIPITATION GETS AND TYPE. 00Z MODELS HAVE TRENDED FURTHER NW
WITH LOW PRESSURE TRACK AND ASSOCIATED QPF DEEPER INTO IL WITH
HEAVIER QPF IN SE IL. USED A CONSENSUS OF THE FORECAST MODELS THIS
FORECAST PACKAGE WITH MATCHES BEST TO ECMWF AND GEM MODELS. NAM
MAY BE TOO FAR WEST AND GFS MAY BE TOO FAR EAST WITH QPF FIELDS.

09Z SURFACE MAP SHOWS 1000 MB LOW PRESSURE IN NORTHERN NY STATE
WITH ITS COLD FRONT EXTENDING SW ACROSS SE KY AND CENTRAL TN/MS.
1032 MB HIGH PRESSURE WAS OVER ID/NORTHERN NV AND RIDGING EAST
INTO THE CENTRAL PLAINS. SHOWERS HAVE SHIFTED SE OF THE OHIO RIVER
BUT LOW CLOUDS LINGERED OVER MUCH OF IL INTO EASTERN IA/MO THOUGH
BREAKING UP IN PARTS OF CENTRAL/NE IL AS DRIER AIR FILTERING IN
FROM THE NNW. TEMPS WERE IN THE MID TO UPPER 30S OVER CENTRAL IL
WITH LOWER 40S IN SE IL. 

SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT.

MODELS SIMILAR THROUGH TUE WITH UPPER LEVEL TROF LIFTING OUT OF
THE MIDWEST AND SURFACE HIGH PRESSURE RIDGE BUILDING EAST INTO THE
MID MS VALLEY TONIGHT AND SE STATES TUE. LOW CLOUDS SHOULD
DECREASE DURING THIS MORNING WITH MOSTLY SUNNY SKIES THIS
AFTERNOON AND AMPLE SUNSHINE TUE. SEASONABLE HIGHS TODAY IN THE
MID TO UPPER 40S. MILDER HIGHS TUE IN THE 50S WITH INCREASING
SOUTH FLOW AND 850-925 MB TEMPS. 

A 555 DM 500 MB CUTOFF LOW OVER NW MEXICO NEAR THE NORTHERN BAJA
TO MOVES INTO THE RIO GRANDE RIVER VALLEY BY SUNSET TUE...THEN
TURN NE INTO THE MID MS VALLEY BY SUNSET WED. THIS TO DEVELOP LOW
PRESSURE OFF THE TX COAST AND DEEPEN NE ACROSS THE OHIO VALLEY WED
AND WED NIGHT. CHANCES OF RAIN WILL SPREAD NE ACROSS CENTRAL AND
EASTERN IL WED AFTERNOON AND BE LIKELY IN SE IL. RAIN WILL TURN TO
SNOW WED EVENING THEN DIMINISH OVERNIGHT WED NIGHT FROM WEST TO
EAST. COULD BE SOME LIGHT SNOW ACCUMULATIONS IN SE IL WED NIGHT
BUT WARMER GROUND TEMPERATURES MAY LIMIT ACCUMULATIONS SOMEWHAT.
 
LONG TERM...THURSDAY THROUGH MONDAY.

STRONG UPPER LEVEL TROF DIGGING INTO IL THU/FRI WILL KEEP CHANCE
OF LIGHT SNOW SHOWERS/FLURRIES ESPECIALLY FROM I-74 NE. COLDER
AIR USHERS IN WITH HIGHS IN THE 30S AND HIGHS ONLY NEAR FREEZING
FROM I-74 NORTH FRI. SO THIS WILL BE SOME OF THE COLDEST AIR OF
THIS SEASON WITH 850 MB TEMPS OF MINUS 11-13C. CANADIAN HIGH
PRESSURE TO BUILD SOUTH ACROSS THE GREAT PLAINS INTO TX SAT WITH
UPPER LEVEL TROF STILL LINGERING OVER IL KEEPING IT CHILLY. HIGH
PRESSURE DRIFTS INTO THE EASTERN STATES SUN/MON WITH A RETURN
SOUTHERLY FLOW AND MORE ZONAL UPPER LEVEL FLOW AND TEMPERATURES
MODIFYING. 

HUETTL

&&

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

$$