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000 FXUS63 KILX 270001 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 701 PM CDT SUN OCT 26 2008 .DISCUSSION... ISSUED 200 PM CDT SUN OCT 26 2008 SURFACE COLD FRONT HAS PUSHED TO THE EAST OF THE FORECAST AREA EARLY THIS AFTERNOON AS LOW PRESSURE NORTH OF THE GREAT LAKES CONTINUES TO DEEPEN. TIGHT PRESSURE GRADIENT BETWEEN THE SFC LOW AND CANADIAN HIGH TO OUR NORTHWEST HAS LED TO WIND GUSTS AS HIGH AS 45 MPH ACRS OUR NORTH OVR THE PAST HOUR. LARGE AREA OF CLOUDS ASSOCIATED WITH THE STRONG LOW LEVEL COLD ADVECTION WERE NOTED ACRS SRN MN AND WISCONSIN AND WERE TRACKING QUICKLY TO THE SOUTH...ALONG WITH ISOLATED LIGHT RAIN AND SNOW SHOWERS. SHORT TERM...TONIGHT THROUGH WEDNESDAY MAIN FORECAST CONCERN TONIGHT THRU WEDNESDAY MORNING WL BE WITH THE POTENTIAL FOR FREEZING TEMPERATURES IN ADDITION TO THE STRONG WINDS THIS EVENING. NO REAL SIGNIFICANT MODEL DIFFERENCES DURING THE PERIOD AS AN UPPER LEVEL TROF TAKES UP SHOP ACRS THE ERN LAKES FOR THE NEXT 3 DAYS BRINGING IN THE COLDEST AIR MASS OF THE FALL SEASON. STEEP LOW LVL LAPSE RATES WL CONTINUE TO AID IN PRODUCING STRONG WINDS THIS EVENING BUT WITH THE LOSS OF DAYTIME HEATING... WE SHOULD SEE THE WINDS DIMINISH SOME OVERNIGHT. THE REAL CHALLENGE WL BE WITH THE SOUTHWARD PROGRESSION OF THE CLOUD COVER THIS EVENING ALONG WITH THE LIGHT PRECIPITATION CURRENTLY BEING REPORTED OVR SE MN AND WRN WISCONSIN. FORECAST SOUNDINGS SUGGEST THAT THE AIR MASS LATER THIS EVENING AND OVERNIGHT WILL BE COLD ENOUGH TO SUPPORT FLURRIES AND SPRINKLES ACRS THE NORTH. SEVERAL SHORTWAVES NOTED ON THE WATER VAPOR ROTATING SE ACRS THE NRN PLAINS WILL ACT TO HELP DEEPEN IN THE UPPER TROF ACRS THE ERN LAKES OVR THE NEXT 24 HOURS. MODELS SUGGEST SOME ENERGY TO PUSH JUST TO OUR NORTH THIS EVENING AND OVERNIGHT...AND ACRS THE NE HALF OF THE FCST AREA ON MONDAY WHICH MAY BRING SOME TRACE AMTS OF SNOW AND OR RAIN TO THE AREA. TEMPERATURES WITH THE CLOUD COVER WILL BE A TOUGH CALL WITH THE LATEST MAV GUIDANCE SOME 8 DEGREES WARMER AT SPI OVERNIGHT THAN THE LAST RUN. UPSTREAM OBSERVATIONS ALREADY SHOWING TEMPERATURES HAVE DROPPED INTO THE THE MID 30S ACRS NRN IOWA AND SERN MN THIS AFTN. AM TRENDING CLOSER TO THE COOLER MET/FWC GUID OVERNIGHT WHICH IS BORDERLINE FREEZE ADVSY MONDAY MORNING. DEEP CYCLONIC FLOW ACRS THE AREA ON MONDAY WITH MODELS INDICATING SOME WEAK ENERGY/LIFT PUSHING ACRS THE AREA DURING THE DAY. HAVE HAD MENTION OF SOME SPRINKLES OR FLURRIES ACRS THE AREA DURING THE DAY AND SEE NO REASON TO CHANGE THAT LINE OF THINKING AT THIS POINT. BASED ON 850 TEMP FORECASTS...MOST AREAS WILL HAVE HIGHS ONLY IN THE 40S WITH MAYBE A 50 ACRS THE SOUTHEAST. CLOUD COVER SHOULD DECREASE MONDAY NIGHT INTO EARLY TUESDAY RESULTING IN EVEN COLDER TEMPERATURES TUESDAY MORNING...WITH EARLY MORNING LOWS IN THE 25 TO 30 DEGREE RANGE. THE SURFACE RIDGE AXIS IS FORECAST TO REMAIN WEST OF THE AREA ON TUESDAY WHICH SHOULD KEEP AFTN HIGHS IN THE MID TO UPPER 40S. ANOTHER COLD NIGHT TUESDAY NIGHT AS THE RIDGE AXIS SHIFTS ACRS THE AREA WITH OVERNIGHT LOWS AOB GUID. THE CENTER OF THE COLD AIR MASS WL SHIFT TO OUR EAST DURING THE DAY WEDNESDAY WHICH SHOULD ALLOW AFTERNOON HIGHS TO EDGE CLOSER TO NORMAL...FROM 55 TO 60. LONG TERM...THURSDAY THROUGH SUNDAY MEDIUM RANGE MODELS CONTINUE TO ADVERTISE THE FLOW WL DEAMPLIFY AS THE DEEP EASTERN LAKES TROF SHIFTS OFF THE NEW ENGLAND COAST BY LATE THU OR EARLY FRIDAY. A WEAK SHORTWAVE WILL SHIFT NORTH OF LAKE SUPERIOR ON FRIDAY HELPING TO DRAG A COLD FRONT ACRS THE MIDWEST LATE FRIDAY INTO SATURDAY...BUT WITH LITTLE IN THE WAY OF APPARENT WX FOR OUR AREA. EXTENDED MODELS INDICATING THAT WITH TROFS OFF THE EAST AND WEST COASTS...AND A FAIRLY SIGNIFICANT RIDGE BUILDING OVER THE MIDWEST LATE NEXT WEEKEND...WE SHOULD SEE TEMPS RECOVER NICELY WITH ABOVE NORMAL READINGS FOR LATE DAY 7 AND INTO THE FIRST FULL WEEK OF NOVEMBER. && .AVIATION... ISSUED 700 PM CDT SUN OCT 26 2008 STRONG WINDS BEHIND TODAYS COLD FRONT SLOWLY DIMINISHING AND THE GUSTS SHOULD TAPER OFF BY AROUND MIDNIGHT. GUSTS ARE LIKELY TO REDEVELOP MONDAY WITH DIURNAL MIXING...BUT THEY WILL NOT BE AS STRONG AS TODAY. WRAP AROUND CLOUDS STARTING TO APPROACH TERMINALS...BUT THESE ARE EXPECTEED TO REMAIN VFR FOR THE MOST PART. MAY SEE SOME MVFR CIGS ACROSS KPIA/KBMI/KCMI TERMINALS...BUT WILL KEEP THEM OUT OF THE TAFS FOR NOW UNTIL THE TIMING IS MORE CLEAR. BAK && .ILX WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING FROM 1 AM TO 9 AM CDT MONDAY FOR ILZ027>031- 036>038-040>057-061. WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR ILZ027>031-036>038- 040>057-061. && $$
