749 FXUS63 KILX 271816 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1215 PM CST TUE JAN 27 2004 .DISCUSSION... UPDATED THE FORECAST THIS AFTERNOON TO CONTINUE THE WINTER WEATHER ADVISORY UNTIL 6 PM. PERIODS OF LIGHT SNOW NORTH OF I-70 DIMINISHING TO FLURRIES WITH LESS THAN 1 INCH ADDITIONAL ACCUMULATIONS. BUT WEST TO NORTHWEST WINDS 20 TO 30 MPH AND GUSTY TO CAUSE BLOWING AND DRIFTING OF THE 1 TO 5 INCH SNOW COVER. TEMPS IN THE LOWER 20S SLIPPING INTO THE TEENS DURING THE AFTERNOON. 999 MB LOW IN FAR SE LOWER MICHIGAN NEAR PORT HURON HAS A TROF ARCHING SW ACROSS EASTERN IL NEAR I-57. CUTOFF UPPER LEVEL LOW WAS OVER NW INDIANA. EXPANSIVE AREA OF LIGHT SNOW OVER CENTRAL AND NE IL FROM I-70 NORTH AND PIVOTING SLOWLY EASTWARD. LIGHT SNOW HAS ALREADY DIMINISHED OR ENDED FROM SPRINGFIELD SW. 1041 MB ARCTIC HIGH PRESSURE OVER ALBERTA CANADA AND RIDGING SOUTH ACROSS THE PLAINS STATES INTO EAST TEXAS. STRONG PRESSURE GRADIENT ACROSS IL BETWEEN THESE SYSTEM WITH WNW WINDS 15 TO 25 MPH AND GUSTY FROM 25 TO 35 MPH. TEMPS HAVE SLIPPED INTO THE UPPER TEENS WEST AND LOWER 20S EAST. AS COLD AS 14 AT GALESBURG...12 AT QUINCY AND 13 AT MOLINE. SAINT LOUIS WHICH IS NORMALLY WARMER THAN CENTRAL IL IS AT 17 DEGREES. DEEP LOW PRESSURE AND CUTOFF UPPER LEVEL LOW TO DRIFT NE INTO SOUTHERN ONTARIO BY MIDNIGHT WITH LIGHT SNOW DIMINISHING TO FLURRIES FROM WEST TO EAST DURING THE AFTERNOON WITH AN ADDITIONAL SNOW ACCUMULATIONS UP TO 1 INCH NE AREAS FROM BMI AND CMI NE. WNW WINDS 20 TO 30 MPH AND GUSTS UP TO 35 MPH TO CAUSE BLOWING AND DRIFTING SNOW THIS AFTERNOON...THEN WINDS TO SUBSIDE TOWARD LATE EVENING AND OVERNIGHT. WITH AMPLE LOW CLOUD COVER AND STRONG COLD AIR ADVECTION IN WAKE OF STORM SYSTEM...TEMPS TO CONTINUE TO SLIP INTO THE TEENS ACROSS CENTRAL AND SE IL THIS AFTERNOON. WIND CHILLS TO RANGE FROM 5 BELOW ZERO TO 5 ABOVE. .PREV DISCUSSION... SHORT TERM...TODAY AND WEDNESDAY... UPPER VORT MAX IS CURRENTLY OVER SPRINGFIELD...WITH THE ASSOCIATED SURFACE LOW CENTER OVER EASTERN INDIANA. SURFACE REFLECTION OF THE UPPER SYSTEM IS SEEN AS A TROUGH EXTENDING FROM THE LOW WESTWARD INTO NORTHERN MISSOURI. FIRST BATCH OF SNOW HAS MOVED NORTH THROUGH THE AREA AND CURRENTLY LIES ACROSS THE NORTHERN HALF OF THE CWA. WRAP-AROUND BEHIND THE VORT MAX IS APPROACHING WESTERN ILLINOIS AND EXTENDS AS FAR SOUTH AS SOUTHWEST OF ST LOUIS. AS THIS ACTIVITY CONTINUES TO MOVE EAST...EXPECT SNOW TO CONTINUE THROUGH THE MORNING HOURS. THE SOUTHEASTERN PORTIONS OF THE CWA ARE CURRENTLY GETTING DRY-SLOTTED...BUT THE PRECIPITATION SOUTHWEST OF ST LOUIS STILL HAS A SHOT AT MAKING IT OVER THERE LATER THIS MORNING. AS THE ENTIRE SYSTEM PUSHES EAST LATER TODAY...EXPECT SNOW TO TAPER OFF DURING THE AFTERNOON AND PRETTY MUCH END BY 00Z. INCREASING PRESSURE GRADIENT WILL MAKE WINDS PRETTY STRONG...AND WILL KEEP BLOWING SNOW IN THE FORECASTS AS WELL AS AN ADDITIONAL 1 TO 3 INCHES OF SNOW. CURRENT ADVISORIES WILL BE MAINTAINED. AFTER THIS SYSTEM MOVES EAST...EXPECT QUIET WEATHER FOR WEDNESDAY AND MOST OF WEDNESDAY NIGHT. LONG TERM...THURSDAY AND BEYOND... ATTENTION IN THE LONGER TERM TURNS TO THE EXPECTED PENETRATION OF ARCTIC AIR INTO THE PLAINS STATES AROUND THURSDAY. WILL SIDE WITH THE ETA SOLUTION AS IT NORMALLY HANDLES THESE SITUATIONS BETTER. THE EXTENDED PERIODS OF THE GFS HAVE ALSO TRENDED TOWARD THE ETA. THIS MEANS THAT THE COLD AIR SHOULD PUSH THROUGH IN ERNEST THURSDAY AND THURSDAY NIGHT. WILL MAINTAIN MEAGER CHANCES FOR PRECIPITATION LATE WEDNESDAY NIGHT INTO EARLY THURSDAY. DEPTH OF COLD AIR SUGGESTS THAT MOST OF THE PRECIPITATION TYPE SHOULD BE SNOW...POSSIBLY RAIN OR SNOW IN THE SOUTHEAST THURSDAY. THE EXTENDED GFS STILL TRIES TO BRING A STRONG LOW PRESSURE SYSTEM INTO THE PLAINS DURING THE WEEKEND. THE PREVIOUS RUN OF THE MODEL HAD THE SURFACE LOW WAY TOO FAR NORTH INTO THE COLD AIR. THE LATEST RUN THIS MORNING IS TRENDING FURTHER SOUTH...BUT IS PROBABLY STILL TOO FAR NORTH AS IT BRINGS THE SURFACE LOW INTO MISSOURI BY THE END OF THE DAY SATURDAY. WONT MAKE TOO MANY CHANGES TO THE WEEKEND FORECAST...BUT WILL TREND THE TEMPERATURE GRIDS COLDER FOR THE SECOND HALF OF THE WEEK. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY ENTIRE AREA TODAY. && $$ 04