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000 FXUS63 KILX 251734 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1234 PM CDT SAT OCT 25 2008 .DISCUSSION... ISSUED 1033 AM CDT SAT OCT 25 2008 PERSISTENT UPPER LOW HAS LIFTED NORTHEASTWARD INTO THE GREAT LAKES THIS MORNING...WITH TRAILING VORT MAX EXTENDING SOUTHWARD ACROSS EAST-CENTRAL ILLINOIS. SYNOPTIC SUBSIDENCE BEHIND THE WAVE HAS LED TO PARTIAL CLEARING ACROSS THE WESTERN HALF OF THE KILX CWA...WITH AREAS FURTHER EAST ALONG THE I-57 CORRIDOR STILL REPORTING OVERCAST CONDITIONS. AS WAVE MOVES FURTHER EAST THIS AFTERNOON...DRYING COMING IN AT ALL LEVELS OF THE ATMOSPHERE WILL HELP SKIES BECOME MOSTLY SUNNY ACROSS THE BOARD. HAVE MADE SOME MINOR ADJUSTMENTS TO THE SKY GRIDS TO BETTER ACCOUNT FOR THE EXPECTED TRENDS FOR THE REST OF THE DAY. WITH INCREASING AMOUNTS OF SUNSHINE...FORECAST SOUNDINGS SUGGEST MIXING UP TO ABOUT 850MB...RESULTING IN AFTERNOON HIGH TEMPERATURES IN THE UPPER 50S. IN ADDITION...HIGHER MOMENTUM AIR FROM ALOFT WILL BE MIXED TO THE SURFACE...WITH GUSTY W/SW WINDS DEVELOPING. SHOULD SEE SUSTAINED WINDS IN THE 10 TO 20 MPH RANGE...WITH GUSTS TO AROUND 25 MPH AT TIMES. CURRENT FORECAST HANDLES THINGS WELL...SO NO ZONE UPDATE IS NEEDED AT THIS TIME. && .AVIATION... ISSUED 1234 PM CDT SAT OCT 25 2008 UPPER WAVE HAS PUSHED EASTWARD INTO INDIANA EARLY THIS AFTERNOON...HOWEVER ENOUGH LIFT IS STILL PRESENT ALONG AND EAST OF I-55 TO SUPPORT A HEALTHY CU-FIELD. CEILINGS HAVE GENERALLY RANGED FROM 2000 TO 2500FT AND EXPECT THIS TREND TO CONTINUE FOR THE NEXT FEW HOURS. CLOUDS WILL RAPIDLY DISSIPATE TOWARD SUNSET...SO WILL SCATTER THINGS OUT AT ALL TERMINALS BY 23Z. SOUTHWESTERLY WINDS OF BETWEEN 10 AND 20 MPH WILL BE COMMON THIS AFTERNOON...BEFORE DROPPING OFF A BIT AFTER SUNSET. AS A STRONG COLD FRONT DIVES THROUGH THE AREA ON SUNDAY...WINDS WILL VEER TO W/NW AND BECOME VERY GUSTY. 12Z MODEL DATA SUGGESTS STRONG PRESSURE GRADIENT AND AMPLE MOMENTUM TRANSFER FROM ALOFT TO SUPPORT WIND GUSTS UP TO 30 MPH BETWEEN 14Z AND 18Z...WITH GUSTS POTENTIALLY IN EXCESS OF 40 MPH AFTER 18Z. BARNES && .PREV DISCUSSION... ISSUED 210 AM CDT SAT OCT 25 2008 00Z UPPER AIR CHARTS SHOWED VERTICALLY STACKED LOW ACROSS EAST CENTRAL IOWA...WITH LATEST SATELLITE IMAGES SHOWING IT HAVING PUSHED INTO NORTHERN ILLINOIS. CLOUDS ACROSS CENTRAL AND SOUTHEAST ILLINOIS LARGELY SCATTERED OUT DURING THE EVENING...BUT HAVE BEGUN TO INCREASE AGAIN NORTHWEST OF I-55. MAIN FORECAST ISSUE FOR TODAY DEALS WITH THE BLAST OF COLD AIR THAT IS EXPECTED TO MOVE INTO THE AREA SUNDAY AND SUNDAY EVENING...AS WELL AS THE ACCOMPANYING WINDY CONDITIONS. SHORT TERM...TODAY THROUGH MONDAY... CLOSED UPPER LOW EXPECTED TO DEGENERATE INTO A WAVE AS IT LIFTS NORTHEAST INTO MICHIGAN TODAY. EXPECT ANY LINGERING PRECIPITATION WITH THIS FEATURE TO REMAIN TO OUR NORTH. EARLY MORNING CLOUDINESS SHOULD GIVE WAY TO MOSTLY SUNNY CONDITIONS BY LATE AFTERNOON...AS HIGH PRESSURE PASSES TO OUR SOUTH. COLDEST AIR OF THE SEASON EXPECTED TO BEGIN MOVING INTO THE AREA ON SUNDAY...AS FRONTAL BOUNDARY PUSHES SOUTHEAST. WHILE SOUTHEAST CWA WILL SEE TEMPERATURES RISE INTO THE 60S ON SUNDAY AFTERNOON... NORTHWEST PORTIONS ARE EXPECTED TO HAVE FALLING TEMPERATURES INTO THE 40S. COLD AIR WILL ARRIVE IN EARNEST BY MONDAY MORNING. MUCH OF THE FORECAST AREA IS EXPECTED TO SEE ITS FIRST FREEZING CONDITIONS OF THE SEASON. HARD FREEZE IS LIKELY ACROSS THE NORTHERN CWA...WITH TEMPERATURES FALLING INTO THE UPPER 20S. WELL BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH THE DAY. ANOTHER SIGNIFICANT FACTOR WILL BE THE WINDS BEHIND THE FRONT. 150 KT JET EXPECTED TO BE JUST TO OUR NORTH BY MIDDAY SUNDAY...WITH 50 KTS ALOFT AS LOW AS 800 MB. SUSTAINED SURFACE WINDS OF 20-30 MPH WILL BE LIKELY ACROSS MUCH OF THE FORECAST AREA LATE SUNDAY MORNING THROUGH THE AFTERNOON...GUSTING IN THE MID 30S. MAY NEED A WIND ADVISORY AT SOME POINT...BUT WILL DEFER THE DECISION TO DAY SHIFT FOR NOW. LONG TERM...TUESDAY THROUGH FRIDAY... QUIET WEATHER EXPECTED INTO THE MIDDLE OF THE WEEK...AS HIGH PRESSURE RIDGE BUILDS EAST ACROSS THE MISSISSIPPI VALLEY. SIGNIFICANT TEMPERATURE RECOVERY EXPECTED AS THE WEEK PROGRESSES...WITH SOUTHWEST WINDS RESULTING FROM HIGH PRESSURE CENTER MOVING ACROSS THE LOWER MISSISSIPPI VALLEY. NO CHANGES MADE TO THE FORECAST BEYOND WEDNESDAY MORNING. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
