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000 FXUS63 KILX 250454 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1154 PM CDT FRI OCT 24 2008 .DISCUSSION... ISSUED 900 PM CDT FRI OCT 24 2008 PCPN MOVING OUT OF THE AREA THIS EVENING. HOWEVER...UPPER LEVEL SYSTEM AND SFC SYSTEM IS STILL WEST OF THE AREA AND WILL BE MOVING ACRS THE CWA OVERNIGHT. WIDELY SCATTERED/ISOLATED SHOWERS AREA STILL POSSIBLE OVERNIGHT SO WILL LEAVE A 20PCT CHC IN THE FORECAST FOR NOW. WILL HAVE TO WATCH TEMPS CAREFULLY OVERNIGHT...BUT WITH CLOUD COVER TEMPS COULD REMAIN STEADY. FOR NOW WILL LEAVE TEMPS ALONE. UPDATE COMING OUT SHORTLY. AUTEN && .AVIATION... ISSUED 1155 PM CDT FRI OCT 24 2008 PCPN HAS MOVED OUT OF THE AREA BUT ADDITIONAL VFR CLOUD COVER IS BEGINNING TO MOVE BACK INTO THE AREA FROM THE NORTHWEST. BELIEVE PIA AND BMI WILL BE PREDOMINATELY BKN WHILE SPI...DEC AND CMI WILL BE SCT WITH TEMPO BKN FROM 06-10Z. BASED ON SATELLITE LOOP...APPEARS TO BE ANOTHER BREAK IN THE CLOUDS THAT SHOULD REACH THE AREA BY MORNING. DO EXPECT STRATOCU TO DEVELOP AT ALL SITES TOMORROW WITH LOTS OF LOW LVL MOISTURE IN THE AREA. BELIEVE WE COULD HAVE BKN CLOUDS FOR A TIME PERIOD THIS AFTERNOON...WHICH WOULD BE CONSISTENT WITH SIMILAR CONDITIONS SEE OUT WEST TODAY. THEN EXPECT SYSTEM TO CONTINUE TO LIFT NORTHWARD TOMORROW AFTERNOON/EVENING WHICH SHOULD BRING CLEARING SKIES FOR THE NIGHT. WINDS WILL REMAIN SOUTHEASTERLY THROUGH THE PERIOD WITH STRONGER WINDS DURING THE DAY TOMORROW. AUTEN && .PREV DISCUSSION... ISSUED 200 PM CDT FRI OCT 24 2008 UPPER LOW CURRENTLY OVR EAST CENTRAL IOWA WILL CONTINUE TO SLOWLY SHIFT EAST AND NORTH OVER THE NEXT 24 HOURS. SEVERAL VORT LOBES WERE ROTATING AROUND THE UPPER LOW AND HAVE COMBINED WITH DAYTIME HEATING TO HELP TO EXPAND THE AREA OF SHOWERS ACRS ERN IOWA AND THE WESTERN HALF OF ILLINOIS. EVEN HAD A LIGHTNING STRIKE SHOW UP OVR THE PAST HOUR NEAR PEORIA. UPPER WAVE OVR CNTRL CANADA EARLY THIS AFTN WL HELP TO PUSH THE UPPER LEVEL WAVE OFF TO OUR NORTHEAST ON SATURDAY. PATTERN ACRS NORTH AMERICA WL BECOME AMPLIFIED AS THE NEXT SHORTWAVE DEEPENS IN OVER THE GREAT LAKES ON SUNDAY BRINGING THE COLDEST AIR MASS TO THE MIDWEST SO FAR THIS FALL SEASON. SHORT TERM...TONIGHT THROUGH MONDAY MODELS VERY SIMILAR DURING THE PERIOD...ALTHOUGH THE NAM-WRF CONTINUES TO ADVERTISE A QUICKER FROPA ON SUNDAY COMPARED WITH THE GFS/GFS ENSEMBLE MEAN. AM TENDED TO SIDE MORE WITH THE NAM- WRF MODEL AS IT SEEMS TO HAVE A BETTER TRACK RECORD IN HANDLING THE COLD AIR INTRUSIONS IN THE MIDWEST. UPPER WAVE IS FORECAST TO WEAKEN AS IT GETS ABSORBED BY A NRN STREAM WAVE ON SATURDAY. THE LAST OF THE SHORTWAVES ROTATING AROUND THE UPPER SYSTEM WL PRODUCE SCATTERED SHOWERS MAINLY ACRS THE NORTH HALF OF THE FCST AREA TNT WITH THE PRECIP SHIFTING NORTH AND EAST OF THE AREA SATURDAY MRNG. NEXT UPPER WAVE COMING SOUTHEAST OUT OF CNTRL CANADA WILL ACT TO AMPLIFY THE PATTERN OVR THE LOWER 48 EARLY NEXT WEEK. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS SLATED TO MOVE THRU ON SUNDAY ACCOMPANIED BY GUSTY WINDS AND COLDER TEMPERATURES...ESPECIALLY LATE IN THE DAY. BEST UPPER LEVEL FORCING AND JET SUPPORT CONTINUES TO SUGGEST ANY PRECIP WITH THE FRONT WL BE TO OUR NORTH AND EAST. MODELS SHOWING A RATHER DEEP TROF OVER THE GREAT LAKES EARLY NEXT WEEK WHICH WILL HELP BRING IN FREEZING TEMPERATURES TO MOST OF THE FORECAST AREA...STARTING IN AREAS NORTH OF I-72 MONDAY MRNG. LONG TERM...TUESDAY THROUGH FRIDAY THE SFC RIDGE AXIS WILL BE CLOSE TO THE AREA TUESDAY MRNG AND THAT APPEARS TO BE THE PRIMARY TIME FOR A HARD FREEZE OVR MOST OF THE FORECAST AREA WITH EARLY MORNING LOWS IN THE UPPER 20S TO LOWER 30S. MEDIUM RANGE MODELS REALLY START TO DIVERGE AFTR WEDNESDAY WITH RESPECT TO THE DEEP UPPER TROF TO OUR EAST AND HOW QUICKLY THAT WL BE MOVING AWY FROM THE MIDWEST. MODELS SUGGEST THE UPPER TROF WL SHIFT INTO THE EASTERN PORTION OF THE COUNTRY BY WEDNESDAY OF NEXT WEEK ALLOWING UPPER LEVEL HEIGHTS TO RISE OVR THE MIDWEST. THIS SHOULD BRING A MODERATING TREND TO THE AREA WED MORNING. HOWEVER...THE LATEST ECMWF BRINGS SHORTWAVE ENERGY SE OUT OF CANADA HELPING TO CARVE OUT ANOTHER TROF OVR THE LAKES REGION...WHICH WOULD BRING ANOTHER SHOT OF COOL AIR TO THE REGION FOR THE SECOND HALF OF NEXT WEEK. THIS SOLUTION IS ABOUT 180 DEGREES OUT OF PHASE WITH THE GFS/GFS ENSEMBLES SO AT THIS POINT AM INCLINED TO SIDE MORE WITH THE GFS SOLUTIONS WITH THE RIDGE BUILDING ACRS THE CNTRL US...WHILE ANY SHORTWAVE TRACKING SE OUT OF CANADA WL REMAIN WELL TO OUR NORTH. NO SIGNIFICANT CHANGES WL BE MADE TO THE EFP WITH TEMPERATURES STARTING OUT BELOW NORMAL AND RETURNING TO NEAR NORMAL AS WE HEAD TOWARDS THE END OF THE PERIOD...WITH LITTLE IF ANY SIGNIFICANT PRECIP EXPECTED NEXT WEEK. SMITH && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
