Issued by NWS Central Illinois
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000 FXUS63 KILX 270452 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1152 PM CDT SUN OCT 26 2008 .DISCUSSION... ISSUED 859 PM CDT SUN OCT 26 2008 WRAP AROUND MOISTURE AND COLD AIR IN THE WAKE OF TODAYS STRONG COLD FRONT AND UPPER WAVE WILL CONTINUE TO SINK INTO THE REGION OVERNIGHT. WINDS HAVE FALLEN BELOW ADVISORY LEVELS WITH THE LOSS OF DIURNAL HEATING...BUT A STRONG PRESSURE GRADIENT WILL KEEP WINDS OVER 10 KTS AND GUSTY ACROSS MOST LOCATIONS THROUGH THE NIGHT. THE CLOUDS WRAPPING INTO THE REGION TONIGHT AND WINDS STAYING UP IS USUALLY NOT A GOOD RECIPE FOR VERY COLD CONDITIONS. HOWEVER...THE STRONG LOW LEVEL COLD/DRY ADVECTION ALONE SHOULD ALLOW TEMPERATURES TO FALL TO FREEZING OR COOLER IN MUCH OF CENTRAL ILLINOIS BY MORNING. RADAR RETURNS PERSIST IN THE WRAP AROUND MOISTURE...ALONG WITH SOME GROUND TRUTH OF FLURRIES/LIGHT SNOW. SEE NO REASON THIS WILL NOT PERSIST AS THIS MOISTURE SLIDES ACROSS THE REGION LATER TONIGHT...THOUGH THE RATHER SHALLOW MOISTURE DEPTH SHOULD KEEP PRECIPITATION FORMATION TO A MINIMUM. PLAN ON UPDATING ZONES/GRIDS FOR THE LATEST TRENDS...AND MOST OF THE CHANGES WILL BE MINOR. HOWEVER...WILL EXPAND THE FLURRY/LIGHT SNOW RISK A BIT FURTHER SOUTH BASED ON LATEST SATELLITE/RADAR TRENDS. BAK && .AVIATION... ISSUED 1152 PM CDT SUN OCT 26 2008 GUSTY WINDS HAVE HELD UP A BIT BETTER THAN PREVIOUSLY EXPECTED. WHILE THEY HAVE DECREASED...APPARENTLY THE PRESSURE GRADIENT...IN COMBINATION WITH SUBSIDENCE IN THE STRONG COLD ADVECTION PATTERN... IS COMPENSATING FOR THE LOSS OF DIURNAL MIXING. SO...EXPECT GUSTY NORTHWEST WINDS TO LINGER UNTIL DIURNAL HEATING HIS LOST MONDAY EVENING...AROUND THE SAME TIME THE SURFACE PRESSURE GRADIENT BEGINS TO RELAX. OTHERWISE...WRAP AROUND CLOUDS WILL CONTINUE TO SPREAD ACROSS THE TERMINALS THROUGH MONDAY EVENING...WHEN THEY SHOULD TEND TO SCATTER OUT. LOW END VFR CIGS SHOULD PREVAIL...BUT A PERIOD OF MVFR CIGS IS LIKELY FOR THE NEXT FEW HOURS... ESPECIALLY ACROSS KPIA/KBMI/KCMI TERMINALS. A FEW FLURRIES OR SPRINKLES ARE ALSO POSSIBLE...BUT WILL NOT BE HEAVY ENOUGH TO CAUSE A VISIBILITY RESTRICTION. BAK && .ILX WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING UNTIL 9 AM CDT MONDAY FOR ILZ027>031-036>038- 040>057-061. && $$
