940 FXUS63 KILX 081116 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 516 AM CST THU MAR 8 2012 .DISCUSSION... ISSUED 314 AM CST THU MAR 8 2012 COLD FRONT PUSHING THROUGH THE FORECAST AREA THIS MORNING WITH SOME SHOWERS OUT AHEAD AND ALONG. A SECOND ROUND OF SHOWERS AND OCCASIONAL THUNDER PUSHING UP JUST BEHIND THE SFC BOUNDARY AS A WAVE MOVES NE INTO THE REGION. MORNING PRECIP AND HOW LONG IT WILL IMPACT THE REGION IS THE FIRST ISSUE...ALONG WITH THE HOURLY TEMPS THIS MORNING AS COLDER AIR MOVES INTO THE AREA. BEYOND THAT...THE FORECAST HAS FEW CHANGES AS THE MODELS STILL WORK OUT HOW THE MAIN UPPER LOW OVER THE SWRN CONUS IS GOING TO MOVE OUT AND ACROSS THE ERN HALF OF THE COUNTRY. STILL MORE IN FAVOR OF THE ECMWF...AND HAVE TRIED TO MITIGATE THE GFS IMPACTS IN THE EXTENDED AS MUCH AS COLLABORATION AND CONSENSUS WOULD ALLOW. THAT BEING SAID...THE GFS SOLUTION OF SPLITTING THE WAVE INTO SEVERAL SMALLER WAVES IS SLOWLY TURNING INTO A MORE ECMWF/NAM SOLUTION. BIGGEST IMPACT FOR THIS PARTICULAR DISCREPANCY WILL BE ON MON NIGHT/TUESDAY WHERE THE CONFIDENCE IN THE GOING FORECAST DECREASES. SHORT TERM...TODAY AND TOMORROW... HIGH TEMPERATURES LIKELY TO BE MET EARLY AS THE REMAINDER OF THE DAY WILL BE COOLER WITH THE FRONT PASSING THROUGH THIS MORNING. PRECIP WILL CONTINUE WITH A CHANCE FOR SOME THUNDER THIS MORNING WITH SOME STEEPER MID LEVEL LAPSE RATES ASSOCIATED WITH THE WAVE MOVING THROUGH THE FLOW JUST BEHIND THE SFC BOUNDARY. POPS DECREASING NW TO SE AFTER 18Z. TEMPS A BIT COOLER TONIGHT. CONCERN THAT GUIDANCE AND GOING FORECAST ARE NOT QUITE COOL ENOUGH SHOULD THE SKIES CLEAR A BIT MORE QUICKLY THAN THE MODEL RH PROFILES ARE HINTING. RATHER DRY AIR AVAILABLE BEHIND THIS WAVE. TOMORROW...TEMPS COOLER THAN LAST COUPLE OF DAYS...BUT STILL A BIT WARMER THAN SEASONABLE...UPPER 40S/NEAR 50 WITH PLENTY OF SUNSHINE. LONG TERM...SATURDAY THROUGH WEDNESDAY... WINDS COME AROUND TO MORE SOUTHERLY SATURDAY MORNING...AND ASSISTS IN A WARM UP WITH PLENTY OF SUNSHINE EARLY. HOWEVER...SOME OF THIS WARM UP WILL BE SHORT LIVED AS A DEVELOPING SYSTEM MOVES OUT OF THE SRN PLAINS INTO THE MIDWEST. MODELS HAVE HAD QUITE THE HISTORY WITH THIS SYSTEM...AND MANY MANY DIFFERENT SOLUTIONS. FOR NOW...THE EC IS PUSHING THE SYSTEM THROUGH...RATHER DIFFUSE AS AN OPEN WAVE...AND WEAKENING AND LESSENING THE QPF TRENDS IN THE LAST COUPLE OF RUNS. THE GFS IS ALSO EASING A BIT...BUT DELIVERING THE PRECIP IN A ONE TWO PUNCH FOR SAT NIGHT/SUN AND MON NIGHT/TUES. FOR NOW...BEST CHANCES FOR POPS ARE IN THE FORECAST WITH SUNDAY AND SUNDAY NIGHT. FROM TUES NIGHT THROUGH WED...KEEPING THE FORECAST DRY AT THIS POINT AS THE MODELS ARE STRUGGLING WITH A BIT OF FEEDBACK IN WEAK SWRLY FLOW. HJS && .AVIATION... ISSUED 516 AM CST THU MAR 8 2012 COLD FRONT HAS PASSED THROUGH THE TAF SITES THIS MORNING...WITH A BRIEF LULL IN THE PRECIPITATION. SHOWERS WILL RAMP UP AGAIN EARLY AS A SHORTWAVE MOVES FROM NORTHERN MO ACROSS CENTRAL IL. SINCE LIGHTNING HAS DECREASED IN THE PAST COUPLE OF HOURS...WILL JUST HAVE SOME VCTS IN THE MORNING. PRECIPITATION MAY MIX WITH LIGHT SNOW OR LIGHT SLEET AT PIA AS TEMPERATURES FALL THROUGH THE 30S ON THE BACK EDGE OF THE RAIN SHIELD. THE LATEST RUN OF THE HRRR MODEL HAS A DECENT HANDLE ON THE CURRENT WEATHER...SO WILL FOLLOW THIS AND EXPECT PRECIPITATION TO END AT PIA 15Z-16Z...AND AT CMI AROUND 18Z. CEILINGS/FLIGHT RULES VARY WIDELY OVER THE AREA THIS MORNING...BUT EXPECT GENERAL MVFR CONDITIONS WITH POSSIBLY IFR IN HEAVIER SHOWERS. OVERALL EXPECT IMPROVEMENT TO VFR A COUPLE OF HOURS AFTER PRECIPITATION ENDS...THEN MAINLY CLEAR SKIES BY 00Z FRI. NORTHWEST WINDS WILL STILL BE ON THE STRONG SIDE TODAY WITH 18-22 KT SUSTAINED WITH GUSTS ABOVE 30 KT AT TIMES. WINDS WILL THEN DIMINISH AND BACK TO WESTERLY AFTER 00Z FRI. 04 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$