FXUS63 KILX 261759
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1159 AM CST SAT DEC 26 2009
.DISCUSSION...
ISSUED 1043 AM CST SAT DEC 26 2009
ISSUED WINTER WEATHER ADVISORY UNTIL 9 PM CST FROM FULTON...
TAZEWELL AND WOODFORD COUNTIES NORTH FOR ADDITIONAL 1 TO 3 INCHES
OF SNOW INTO EARLY EVENING GIVING STORM TOTAL OF 3 TO 5 INCHES
WITH LOCALLY HIGHER AMOUNTS FROM PEORIA NORTH. SSW WINDS 15 TO 20
MPH AND GUSTS OF 20 TO 30 MPH WILL CAUSE SOME BLOWING AND DRIFTING
SNOW ESPECIALLY IN OPEN/EXPOSED AREAS INTO THIS EVENING. AREAS
FROM PEORIA NORTH HAVE SEEN 2 TO 5 INCHES OF SNOW SINCE MIDNIGHT.
RADAR MOSAIC AND SURFACE OBSERVATIONS CONTINUE TO SHOW WIDESPREAD
SNOW NORTH OF I-72 WITH HEAVIER SNOW BURSTS FROM PEORIA NORTH
WHERE VISIBILITIES DROP TO A HALF MILE AT TIMES. 1003 MB LOW
PRESSURE WAS OVER SE IA WHILE VERY STRONG 519 DM 500 MB LOW WAS
OVER CENTRAL WI WITH ITS SHORT WAVE TROF EXTENDING ACROSS SE IA
AND CENTRAL MO. MODELS SHOW SHORT WAVE TROF MOVING INTO IL BY
SUNSET AND SOME STRONG SHORT WAVES CONTINING TO PIVOT AROUND UPPER
LEVEL LOW OVER IL ALONG WITH SOME ISENTROPIC LIFT ESPECIALLY OVER
THE IL RIVER VALLEY TO CONTINUE LIGHT SNOW OVER CENTRAL IL UNTIL
MID EVENING. SURFACE LOW CONTINUES TO WEAKEN AS IT LIFTS NE INTO
SOUTHERN WI THIS EVENING BUT PRESSURE GRADIENT STILL STRONG
ENOUGH TO GENERATE GUSTY SSW WINDS 20 TO 30 MPH TODAY. SE IL WILL
JUST SEE A FEW LIGHT SNOW SHOWERS AND FEW PEAKS OF SUNSHINE ALONG
WITH MILDER HIGHS IN THE MID 30S...WHILE HIGHS 25 TO 30F OVER
CENTRAL IL.
HUETTL
&&
.AVIATION...
ISSUED 1155 AM CST SAT DEC 26 2009
MVFR CONDITIONS WILL GENERALLY PREVAIL NEXT 24 HOURS ACROSS THE
CENTRAL IL TERMINALS. THOUGH PERIODS OF LIGHT SNOW THIS AFTERNOON
AND EARLY EVENING AND AGAIN LATER TONIGHT AND SUNDAY MORNING WILL
BRING IFR CONDITIONS AT TIMES AND POSSIBLY EVEN BRIEFLY LIFR. BRISK
SSW WINDS 10 TO 18 KTS WITH GUSTS OF 19 TO 27 KTS WILL OCCUR THIS
AFTERNOON AND THEN DIMINISH TO 10 TO 15 KTS TONIGHT AND SUNDAY
MORNING AS WINDS TURN MORE WEST. MIDDAY SURFACE MAP SHOWS 1004 MB
LOW PRESSURE OVER SE IA WITH VERY STRONG 519 DM 500 MB LOW OVER
CENTRAL WI. MODELS CONTINUE TO WEAKEN SURFACE LOW AS IT MOVES NE
TO LAKE MI BY MIDNIGHT AND NORTHERN LOWER MI BY 18Z/NOON SUNDAY.
VERY STRONG UPPER LEVEL LOW WILL STAY OVER CENTRAL/SE WI INTO SUNDAY.
SHORT WAVES ROTATING AROUND UPPER LEVEL LOW OVER IL WILL BRING
PERIODS OF LIGHT SNOW THIS AFTERNOON/EARLY EVENING AND NEXT ROUND
LATE TONIGHT/SUNDAY MORNING AND DIMINISH EARLY SUNDAY AFTERNOON.
HUETTL
&&
.PREV DISCUSSION...
ISSUED 245 AM CST SAT DEC 26 2009
LIGHT SNOW ACCUMULATIONS LIKELY TODAY AND SUNDAY...AS DEEP UPPER
LOW REMAINS IN THE VICINITY.
SHORT TERM...TODAY THROUGH MONDAY
MAIN WEATHER MAKER THIS WEEKEND WILL BE A DEEP UPPER LOW CURRENTLY
ANALYZED OVER NORTH-CENTRAL ILLINOIS. NUMEROUS SHORT-WAVES WILL
ROTATE AROUND THE PARENT LOW...BRINGING OFF AND ON SNOW-SHOWERS TO
THE AREA. 07Z WATER VAPOR IMAGERY SHOWS IMPRESSIVE WAVE OVER
WESTERN IOWA/EASTERN NEBRASKA...WHILE A WEAKER FEATURE IS CROSSING
THE MISSISSIPPI RIVER INTO WEST-CENTRAL ILLINOIS. INITIAL DISTURBANCE
IS ALREADY TRIGGERING LIGHT SNOW ALONG AND WEST OF I-55...WITH
MANY OB SITES REPORTING VISBYS IN THE 2 TO 4SM RANGE. THIS AREA OF
LIGHT SNOW WILL LIFT E/NE EARLY THIS MORNING...MAINLY IMPACTING
LOCATIONS ALONG AND NORTH OF I-72. STRONGER WAVE TO THE WEST WILL
GRADUALLY WORK ITS WAY INTO CENTRAL ILLINOIS TOWARD MIDDAY...WITH
BOTH THE NAM-WRF AND GFS TAKING THE CENTER OF THE VORT MAX FROM
NEAR KUIN AT 18Z TO KIKK BY 00Z. THE CORRESPONDING VALUES OF OMEGA
ARE HIGHEST ALONG AND NORTH OF THE VORT PATH DURING THE AFTERNOON.
FORECAST SOUNDINGS INDICATE AMPLE MID AND LOW-LEVEL MOISTURE IN
CONJUNCTION WITH THE FORCING ASSOCIATED WITH THE WAVE..WHICH WILL
LEAD TO OCCASIONAL SNOW SHOWERS ACROSS THE N/NW KILX CWA. HAVE
INCREASED POPS TO CATEGORICAL ALONG AND NORTHWEST OF A RUSHVILLE
TO BLOOMINGTON LINE...WHERE AROUND 1 INCH OF SNOW WILL ACCUMULATE
BY LATE AFTERNOON. LOCALIZED 2 INCH AMOUNTS WILL BE POSSIBLE AS
WELL...ESPECIALLY IMMEDIATELY UNDER THE APPROACHING VORT MAX.
FURTHER SOUTH AND EAST...POPS WILL STEADILY DECLINE...WITH ONLY
30S SOUTH OF I-70.
AFTER MAIN SHORT-WAVE PUSHES INTO NORTHERN INDIANA...WEAK SUBSIDENCE
IN ITS WAKE WILL BRING A TEMPORARY LULL TO THE SNOW-SHOWERS THIS
EVENING. YET ANOTHER WAVE ROTATING AROUND THE SLOW-MOVING UPPER LOW
WILL APPROACH FROM THE NORTHWEST AFTER MIDNIGHT...BRINGING A
RENEWED CHANCE FOR PRECIP BACK INTO CENTRAL ILLINOIS. WILL
THEREFORE CARRY SCATTERED SNOW SHOWERS TONIGHT...WITH THE BEST
CHANCE FOR SNOW AFTER MIDNIGHT. SNOW SHOWERS WILL CONTINUE INTO
SUNDAY...WITH LESS THAN ONE INCH ADDITIONAL ACCUMULATION EXPECTED.
ONE FINAL WEAK WAVE PUSHES THROUGH THE AREA SUNDAY EVENING...BEFORE
THE WHOLE SYSTEM FINALLY BEGINS TO PULL FURTHER AWAY LATE SUNDAY
NIGHT. NOT REALLY SEEING MUCH IN THE WAY OF OMEGA WITH THIS
LAST FEATURE...HOWEVER THINK A MENTION OF SCATTERED SNOW FLURRIES
WOULD BE PRUDENT...ESPECIALLY SUNDAY EVENING. UPPER LOW WILL BE
SLOW TO EXIT ON MONDAY...WHILE SURFACE RIDGING REMAINS TO THE WEST
ACROSS THE PLAINS. DESPITE INCREASING SUBSIDENCE/DRYING AT MID-
LEVELS...LOW-LEVELS WILL REMAIN MOIST. WILL THEREFORE MAINTAIN
MOSTLY CLOUDY SKIES THROUGH MONDAY MORNING...BEFORE CLEARING
THINGS OUT MONDAY AFTERNOON. WITH HIGH PRESSURE EXPECTED TO SHIFT
TO ALONG THE MISSISSIPPI RIVER BY 12Z TUE...CLEAR SKIES AND LIGHT
WINDS WILL MAKE MONDAY NIGHT THE COLDEST NIGHT IN THE FORECAST
PERIOD. HAVE UNDERCUT GUIDANCE BY A FEW DEGREES...ESPECIALLY
ACROSS THE N/NW WHERE A DECENT SNOW-COVER WILL BE IN PLACE. LOW
TEMPS BY EARLY TUESDAY MORNING WILL RANGE FROM AROUND 10 DEGREES
FAR NORTHWEST...TO 20 DEGREES FAR SOUTHEAST.
LONG TERM...TUESDAY THROUGH FRIDAY
MOSTLY SUNNY AND DRY WEATHER WILL BE ON TAP TUESDAY...BEFORE THE
NEXT APPROACHING SYSTEM SPREADS CLOUDS INTO THE AREA TUESDAY NIGHT
AND WEDNESDAY. MODELS IN FAIRLY GOOD AGREEMENT...FEATURING A
NORTHERN STREAM SYSTEM SKIRTING ACROSS SOUTHERN CANADA AND A
SOUTHERN STREAM FEATURE TRACKING ALONG THE GULF COAST. WITH THE
TWO SYSTEMS REMAINING UNPHASED...FORCING WILL BE WEAK ACROSS
CENTRAL ILLINOIS...SO PRECIP CHANCES SHOULD REMAIN RATHER MEAGER.
WILL INTRODUCE SLIGHT CHANCE POPS FOR LIGHT SNOW TUESDAY
NIGHT...THEN LINGER THEM THROUGH WEDNESDAY...AS NORTHERN STREAM
WAVE DRIVES A COLD FRONT THROUGH ILLINOIS. AFTER THAT...MUCH
COLDER AIR WILL SETTLE INTO THE REGION FOR THE END OF NEXT WEEK.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
ILZ027>031-036-037.
FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR ILZ051.
&&
$$
