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000 FXUS63 KILX 240454 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1154 PM CDT THU OCT 23 2008 .DISCUSSION... ISSUED 848 PM CDT THU OCT 23 2008 LARGE AREA OF RAIN CONTINUES TO SPREAD NORTH ACROSS THE STATE THIS EVENING. BASED ON RADAR MOSAIC LOOP EXPECT THIS TO CONTINUE OVERNIGHT...ESPECIALLY IN EASTERN PARTS OF CWA. CURRENT FORECAST FOR OVERNIGHT HAS A GOOD HANDLE ON CURRENT SITUATION AND DO NOT SEE ANY NEED TO UPDATE AT THIS TIME. THEREFORE...NO UPDATE REQUIRED AT THIS TIME. AUTEN && .AVIATION... ISSUED 1155 PM CDT THU OCT 23 2008 SKY COVER HAS BECOME VFR AT ALL TAF SITES. EVEN WITH RAIN OCCURRING...BASES ARE QUITE HIGH. EVEN VIS IS VFR CAT. THIS DOES NOT QUITE MATCH WITH RH FIELDS IN NAM MODEL BUT SEEMS TO BETTER MATH WHAT GFS RH FIELDS SHOW. SO NEW TAFS WILL HAVE BETTER CIG HEIGHTS UNTIL TOMORROW WHEN THE UPPER LVL SYSTEM PUSHES INTO THE AREA. SO...VFR CONDITIONS OVERNIGHT WITH CIGS AROUND 5-6KFT AND UNRESTRICTED VIS. COULD EVEN BE SOME BREAKS IN THE CLOUDS TOMORROW AS DRIER AIR ADVECTS INTO THE REGION FROM THE SOUTH. HOWEVER...AS SUN HEATS THIS AIR UP...SC WILL DEVELOP IN THE AREA AND SCATTERED SHOWERS WILL BE POSSIBLE. THIS WAS THE CASE OUT WEST UNDER THE LOW TODAY AND WOULD EXPECT SIMILAR WEATHER IN OUR AREA TOMORROW. SO WILL BE KEEPING VCSH AT ALL TAF SITES FOR LATE MORNING AND INTO AFTERNOON. ALSO APPEARS THAT CLOUDS WILL BE MVFR WITH THE SHOWERS AND THEN RISE TO VFR FOR THE EVENING. VCSH WILL ALSO CONTINUE INTO THE EVENING HOURS AT ALL SITES AS THE LOW PRESSURE LIFTS ACROSS THE REGION. AUTEN && .PREV DISCUSSION... ISSUED 200 PM CDT THU OCT 23 2008 LATEST SURFACE ANALYSIS INDICATING LOW PRESSURE OVR NORTHEAST KANSAS WITH A FRONTAL BOUNDARY EXTENDING EAST FROM THE LOW INTO EXTREME WESTERN ILLINOIS. BAND OF LIGHT TO MODERATE RAIN CONTINUES TO MOVE NNW ACRS WESTERN AND CNTRL IL WITH SATELLITE AND SFC OBS INDICATING A NARROW DRY SLOT EXTENDING FROM ERN MO NORTH INTO SE IOWA. THE CLOSED UPPER LOW OVER EASTERN KANSAS EARLY THIS AFTERNOON WILL BE THE MAIN WEATHER MAKER FOR THE NEXT COUPLE OF DAYS ACRS CENTRAL ILLINOIS. STRONG COLD FRONT STILL EXPECTED TO PUSH THRU THE AREA ON SUNDAY BRINGING THE THREAT FOR FREEZING TEMPERATURES MONDAY AND TUESDAY MORNINGS. SHORT TERM...TONIGHT THROUGH SUNDAY THE VERTICALLY STACKED SYSTEM TO OUR WEST WILL SLOWLY EDGE EAST ACRS CNTRL ILLINOIS OVR THE NEXT 24 TO 36 HOURS. THE MAIN AREA OF LOW AND MID LEVEL FORCING TO THE EAST OF THE SYSTEM WL CONTINUE TO PUSH THE SOLID AREA OF LIGHT TO MODERATE RAINS ACRS THE FORECAST AREA TNT WITH THE EAST SEEING THE HIGHEST POPS...WHILE ACRS THE FAR WEST...WL CARRY 40 AND 50 POPS THIS EVENING TO TAKE INTO ACCOUNT THE LOW AND MID LVL DRY SLOT THAT WL PUSH ACRS THE AREA. AS THE UPPER LOW TRACKS INTO WRN IL ON FRIDAY...WL CONTINUE TO CARRY RATHER HIGH PRECIP CHANCES ACRS THE FORECAST AREA. FAIRLY DECENT AREA OF RAIN NOW OCCURRING UNDERNEATH THE UPPER LOW AND WE SHOULD SEE THAT TYPE OF WX ACRS CNTRL IL ON FRIDAY. WL HOLD ONTO POPS FRIDAY NIGHT AS THE UPPER LOW TRACKS INTO NE IL WITH DECREASING POPS FROM WEST TO EAST ON SATURDAY AS THE WAVE SHIFTS WELL TO OUR EAST. UP UNTIL SAT NIGHT...MODELS HAVE SHOWN SOME DECENT CONTINUITY...HOWEVER WITH THIS MRNGS RUNS...WE ARE STARTING TO SEE SOME TIMING DIFFERENCES WITH THE COLD FRONT ON SUNDAY WITH THE FASTER NAM-WRF SOLUTION LOOKING MORE REASONABLE AT THIS TIME. THIS IS SUPPORTED NOW BY THE LATEST ECWMF WHICH HAS THE STRONG FRONT PUSHING INTO OUR NW COUNTIES BY 12Z SUNDAY. BEST COLD ADVECTION LAGS ABOUT 6 HOURS BEHIND THE BOUNDARY SO WE MAY ACTUALLY SEE TEMPS REBOUND A BIT LATE SUN MORNING INTO THE AFTN HOURS... ESP ACRS OUR EAST AND SOUTHEAST. WITH THE BEST LIFT LOCATED WELL TO OUR NORTH AND EAST SUNDAY...WL CONTINUE TO CARRY A DRY FORECAST ON SUNDAY AHEAD OF AND BEHIND THE FRONTAL BOUNDARY. LONG TERM...MONDAY THROUGH THURSDAY THE SHORTWAVE THAT SHIFTS SOUTHEAST INTO THE LAKES REGION AND HELPS DEEPEN IN THE TROF OVER THE LAKES WL ONLY GRADUALLY SHIFT OFF THE EAST LATE TUE OR WEDNESDAY OF NEXT WEEK. LARGE CANADIAN HIGH PRESSURE WILL SETTLE SOUTH INTO THE MIDWEST MONDAY AND TUESDAY OF NEXT WEEK. THE ACTUAL SFC RIDGE AXIS IS FORECAST TO FINALLY MOVE INTO OUR AREA BY LATE TUESDAY NIGHT OR WEDNESDAY MORNING...SO THAT MAY BE OUR COLDEST MORNING SO FAR THIS FALL SEASON. HAVE HAD EARLY MRNG LOWS IN 30 TO 35 DEGREE RANGE STARTING MONDAY MRNG AND SEE NO REASON TO MAKE ANY SIG CHANGES AT THIS TIME. MODELS STILL SHOWING SOME VARIABILITY WITH RESPECT TO HOW MUCH LOW LVL CLOUDINESS LINGERS ACRS THE AREA EARLY NEXT WEEK...WHICH WILL AFFECT OVERNIGHT TEMPS. AS THE CENTER OF THE HIGH SHIFTS TO OUR EAST LATE WEDNESDAY INTO THURSDAY...WE SHOULD START TO SEE SOME MODERATING TEMPERATURES TOWARDS THE END OF THE WEEK AS THE UPPER LEVEL FLOW BECOMES MORE ZONAL. SMITH && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
