000 FXUS63 KILX 271840 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1230 PM CST SAT NOV 27 2004 .DISCUSSION... UPDATED THE FORECAST THIS AFTERNOON ADDRESSING PRECIPITATION... TEMPERATURE AND WIND TRENDS. WIDPESPREAD SHOWERS ACROSS ALONG AND AHEAD OF A COLD FRONT NEARING THE IL RIVER CONNECTED TO 997 MB LOW PRESSURE JUST WEST OF MADISON WI. LOW PRESSURE TO DEEPEN TO 995 MB OVER DOOR COUNTY IN FAR NE WI BY 00Z AND SWEEP THE FRONT EAST TO THE IL/IN BORDER BEFORE 00Z PER RUC AND ETA. BRISK SOUTH WINDS 15 TO 25 MPH AND GUSTS OF 25 TO 35 MPH TURN WEST BEHIND THE FRONT AND RAIN DIMINISHES. CONTINUED ISOLATED THUNDER OVER SE IL WITH A MENTION OF FLURRIES OVER NW COUNTIES WHERE PEORIA BRIEFLY HAD SOME FLURRIES WITH THE LIGHT RAIN. TEMPERATURES IN THE MID 40S TO AROUND 50 AHEAD OF THE COLD FRONT TO COOL THROUGH THE 40S BEHIND THE COLD FRONT. LOW CLOUDS TO STICK THROUGH THIS EVENING...THEN CLEARING FROM THE WEST LATER TONIGHT. .PREV DISCUSSION... FORECAST CHALLENGES WILL BE PRECIP AND TEMPS FOR TODAY...AND THE NEXT CHANCES FOR PRECIP THE FIRST HALF OF NEXT WEEK. THE ETA AND GFS WERE VERY SIMILAR WITH THEIR SOLUTIONS INTO EARLY NEXT WEEK... ALTHOUGH NEITHER MODEL DID ANY GOOD WITH THE LOW LEVEL TEMPERATURE FIELDS IN THE MID MS VALLEY FOR TODAY. THE GFS IS THE PREFERRED MODEL FOR THE FIRST PART OF NEXT WEEK BECAUSE IN A SPLIT FLOW SITUATION WHEN A LOW CLOSES OFF IN THE SW U.S. THE SLOWEST SOLUTION IS USUALLY THE WAY TO GO...AND THE ETA IS TOO FAST IN BRINGING OUT UPPER LEVEL ENERGY. SHORT TERM...TODAY THROUGH SUNDAY... RAIN HAS RAPIDLY DEVELOPED IN A ZONE OF WARM ADVECTION ACROSS CENTRAL IL EARLY THIS MORNING...AND AHEAD OF A COLD FRONT THAT EXTENDED FROM CENT IA-WESTERN MO-NE TEXAS. A TONGUE OF HIGHER MOISTURE AHEAD OF THE FRONT AND STRONG LOW LEVEL WIND FIELDS SHOULD CONTINUE TO PRODUCE RAIN ACROSS CENT-EASTERN AND SE IL THIS MORNING. MODERATE RAINFALL AND A SATURATED GROUND FROM RECENT HEAVY WET SNOWS SHOULD PRODUCE PONDING OF WATER...BUT NO FLOODING PROBLEMS ARE ANTICIPATED AT THIS TIME. THE MOISTURE AND WIND FIELDS SHOULD ALSO PROVIDE ENOUGH INSTABILITY FOR SCATTERED T-STORMS IN MUCH OF CENT AND SE IL THIS MORN INTO EARLY AFTERNOON. TEMPS WILL BE FAIRLY STEADY THIS MORNING...THEN SLOWLY DROP AFTER THE FRONTAL PASSAGE THIS AFTERNOON. DUE TO THE STRONG LOW LEVEL WINDS AND A TIGHTENING PRESSURE GRADIENT WITH TIME...WILL BUMP UP THE WINDS A NOTCH TODAY. THE TIMING OF THE COLD AIR BEHIND THE FRONT AND THE END OF THE PRECIP WILL BE CLOSE FOR THE POSSIBILITY OF A SHORT PERIOD OF RAIN MIXED WITH OR CHANGING TO SNOW THE MIDDLE OF THIS AFTERNOON WEST OF THE IL RIVER. WEAK HIGH PRESSURE IS EXPECTED TO FOLLOW THE FRONT GIVING US PARTLY CLOUDY AND COOL CONDITIONS FOR TONIGHT THROUGH SUNDAY. LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... AN UPPER LEVEL TROF APPROACHING THE PAC NW IS EXPECTED TO DIG INTO THE SW U.S. SUNDAY AND CLOSE OFF IN THE FOUR CORNERS REGION MONDAY. BACKING UPPER LEVEL FLOW IN THE MIDWEST WILL RESULT IN MID LEVEL WARM ADVECTION. THIS SHOULD BE ENOUGH TO PRODUCE A CHANCE FOR LIGHT SNOW NORTH OF A GBG-PIA-BMI LINE MONDAY...WITH A CHANCE FOR LIGHT RAIN TO THE SOUTH. AFTER A BREAK IN THE PRECIP LATER MONDAY INTO EARLY TUESDAY...THE UPPER LOW IN THE SOUTHERN STREAM IS EXPECTED TO SHIFT EAST TOWARD THE SOUTHERN PLAINS. THERE IS DISAGREEMENT AMONGST THE MEDIUM RANGE MODELS AS TO WHEN AND HOW FAST THIS WILL HAPPEN... WHICH WILL ULTIMATELY HAVE AN AFFECT ON THE TIMING AND TYPE OF PRECIP FOR TUESDAY AND WEDNESDAY. WILL NOT MAKE ANY MAJOR FORECAST CHANGES AT THIS TIME AS A RESULT. THUS...THERE COULD BE ANOTHER CHANCE FOR SNOW LATE TUESDAY INTO WEDNESDAY FOR NORTHERN AREAS... AND A MIX OF PRECIPITATION IN CENTRAL SECTIONS. THIS IS STILL 4-5 DAYS OFF...SO THERE IS PLENTY OF TIME TO RESOLVE THE SPECIFICS. HOWEVER...ONE BIG DIFFERENCE BETWEEN THE STORM LAST WEEK AND THIS ONE IS THAT THE UPPER LEVEL SPLIT FLOW THAT IS EXPECTED TO BE IN PLACE SHOULD KEEP THE BEST COLD AIR IN THE UPPER GREAT LAKES REGION. THIS SCENARIO USUALLY RESULTS IN A RAIN OR MIXED PRECIP EVENT FOR CENT IL. AFTER THE MID-WEEK WEATHER SYSTEM PASSES THROUGH THE AREA...DRY AND COOL WEATHER IS ANTICIPATED AS UPPER LEVEL CONFLUENT FLOW/SURFACE HIGH PRESSURE DOMINATES. && .ILX WATCHES/WARNINGS/ADVISORIES... .IL...NONE. && $$ HUETTL/MILLER