000 FXUS63 KARX 092350 AFDARX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 550 PM CST THU FEB 9 2012 .SHORT TERM...TONIGHT THROUGH SUNDAY 215 PM CST THU FEB 9 2012 MAIN FORECAST CONTINUES TO BE FOCUSED ON ARCTIC FRONTAL PASSAGE TONIGHT AND ASSOCIATED SNOW SHOWER/FLURRY ACTIVITY INTO FRIDAY. COLDER AIR MASS THROUGH THIS WEEKEND ALONG WITH WIND EXPECTED TO PRODUCE SOME CHILLIER THAN NORMAL TEMPERATURES AND VERY COLD WIND CHILLS...ESPECIALLY ON SATURDAY MORNING. CURRENT SURFACE MAP THIS AFTERNOON HAS THE ARCTIC FRONTAL BOUNDARY OOZING SOUTHWARD ACROSS NORTHERN MN/ND. VISIBLE SATELLITE SHOWING A PATCH OF CUMULUS/STRATOCUMULUS ACROSS MOST OF NORTHEAST IA AND PORTIONS OF SOUTHEAST MN INTO FAR SOUTHWEST WI. OTHERWISE... SOUTHWEST WINDS AHEAD OF THIS FRONTAL BOUNDARY WAS PRODUCING TEMPERATURES IN THE UPPER 20S TO LOWER 30S ACROSS THE FORECAST AREA. HOWEVER...WIND CHILLS WERE MAKING IT FEEL MORE LIKE THE TEENS AND 20S. 09.12Z MODELS IN GOOD AGREEMENT THROUGH THE SHORT TERM. WATER VAPOR IMAGERY/RUC ANALYSIS SHOWING A FAIRLY STRONG MID-LEVEL SHORTWAVE TROUGH ROTATING SOUTHEASTWARD THROUGH ONTARIO/MANITOBA/SASKATCHEWAN THIS AFTERNOON. THIS WILL DRIVE THE ARCTIC FRONT THROUGH THE AREA OVERNIGHT...EXITING SOUTH OF THE AREA BY DAYBREAK. MODELS CONTINUE TO SHOW RATHER VIGOROUS FORCING WITH THE FRONT WITH GOOD 850-300MB PV-ADVECTION/STEEPENING LOW LEVEL 0-1KM LAPSE RATES FOR SCATTERED SNOW SHOWERS. HIGHEST PROBABILITIES FOR THE SNOW SHOWER ACTIVITY APPEARS TO ALONG AND NORTH OF THE I-94 CORRIDOR AFTER MIDNIGHT WITH FLURRY ACTIVITY FILLING IN ELSEWHERE. COULD SEE A FEW TENTHS OF AN INCH OF SNOWFALL OUT OF THE MORE VIGOROUS SNOW SHOWERS. OTHERWISE...LOOK FOR LOWS TOWARD MORNING FALLING INTO THE SINGLE DIGITS AND TEEN ALONG WITH INCREASING NORTH WINDS. COLDEST WIND CHILL VALUES TOMORROW MORNING SHOULD RANGE FROM THE SINGLE DIGITS ACROSS FAR SOUTHWEST WISCONSIN...TO THE SINGLE DIGITS AND TEENS BELOW ZERO ACROSS THE REST OF THE AREA. MUCH COLDER CYCLONIC FLOW WILL LINGER ACROSS THE AREA FRIDAY WITH CONTINUED VERY STEEP LOW LEVEL 0-1KM LAPSE RATES. THIS WILL BE ENOUGH TO CONTINUE GENERATING FLURRIES. WITH 925MB TEMPERATURES PLUMMETING INTO THE TEEN BELOW 0C...LOOK FOR HIGHS TO TOP OFF ONLY IN THE 10-20 DEGREE RANGE. ADDING NORTH WINDS OF 10-25 MPH WILL YIELD WIND CHILLS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. CLEARING SKIES EXPECTED FRIDAY NIGHT AS HIGH PRESSURE BUILDS SOUTHEAST OUT OF THE CENTRAL CANADIAN PROVINCES INTO THE NORTHERN PLAINS/UPPER MISSISSIPPI RIVER REGION. TEMPERATURES DROPPING INTO THE SINGLE DIGITS ABOVE/BELOW ZERO AND NORTH WINDS AROUND 10 MPH ARE EXPECTED TO PRODUCE SOME FRIGID WIND CHILLS IN THE TEENS/LOWER 20S BELOW ZERO. MAY HAVE TO KEEP A WATCH FOR POTENTIAL WIND CHILL HEADLINES LATE FRIDAY NIGHT/EARLY SATURDAY MORNING. SATURDAY EXPECTED TO BE SUNNY BUT REMAINING VERY CHILLY AS HIGH PRESSURE SLIDES DOWN THROUGH THE PLAINS. THIS KEEPS A FAIRLY TIGHT PRESSURE GRADIENT ACROSS OUR AREA WITH FAIRLY BRISK WEST/NORTHWEST WINDS CONTINUING. HIGHS ARE ONLY EXPECTED TO TOP OFF IN THE TEENS ONCE AGAIN WITH WIND CHILLS HOVERING IN THE SINGLE DIGITS ABOVE/BELOW ZERO RANGE. MOSTLY CLEAR SKIES EXPECTED SATURDAY NIGHT THROUGH SUNDAY AS THE RIDGE AXIS SLOWLY BUILDS EAST OVER THE AREA. SOME MODERATION IN TEMPERATURES ALSO EXPECTED WITH LOWS SATURDAY NIGHT IN THE SINGLE DIGITS ABOVE ZERO AND HIGHS ON SUNDAY IN THE 20S. .LONG TERM...SUNDAY NIGHT THROUGH THURSDAY 215 PM CST THU FEB 9 2012 09.12Z GFS AND ECMWF IN GENERALLY GOOD AGREEMENT THROUGH TUESDAY...BUT THEN DIVERGE A BIT AFTER THAT. BOTH MODELS SHOWING GOOD RUN TO RUN CONTINUITY WITH A WEAK MID-LEVEL TROUGH APPROACHING THE AREA SUNDAY NIGHT/MONDAY. GFS SHOWS PRETTY DECENT 275-280K LAYER ISENTROPIC LIFT LATE SUNDAY NIGHT INTO MONDAY AHEAD OF THIS TROUGH. MAY HAVE TO OVERCOME RESIDUAL FAIRLY DRY LOWER LEVELS AS RIDGE AXIS DEPARTS EAST OF THE AREA. FOR NOW...WILL CARRY SMALL-END SLIGHT CHANCE OF -SN ACROSS NORTHEAST IA/SOUTHEAST MN SUNDAY NIGHT AND GO WITH HIGH-END CHANCE POPS/LIKELY POPS SOUTH OF I-90 ON MONDAY AS THE TROUGH CONTINUES TO PUSH EAST ACROSS IA/IL/SOUTHERN WI. PRELIMINARY INDICATIONS ARE THAT THE AREA COULD SEE 1-2 INCHES SOUTH OF I-90...TAPERING OFF TO PERHAPS A DUSTING NORTHEAST IF I-94. TUESDAY/TUESDAY NIGHT LOOK DRY FOR NOW AS AS A WEAK RIDGE MOVES ACROSS THE UPPER MISSISSIPPI RIVER REGION. AS STATED BEFORE...MODELS GET KIND OF SKETCHY FOR WEDNESDAY/THURSDAY DEALING WITH VARIOUS ENERGY IN SPLIT FLOW REGIME ACROSS CANADA/CONUS. THE GFS WANTS TO EJECT A TROUGH NORTHEAST OUT OF THE ROCKIES AND INTO THE REGION WED/WED N FOR A CHANCE OF LIGHT SNOW WHILE THE ECMWF KEEPS THE AREA DRY UNDER GENERAL RIDGING. WILL GO WITH A BLEND FOR NOW WITH A VERY SLIGHT CHANCE OF -SN IN THE GRIDS. && .AVIATION...TONIGHT AND FRIDAY 550 PM CST THU FEB 9 2012 CURRENTLY WATCHING AREA OF MVFR STRATUS / AROUND 2500 FT / ACROSS MUCH OF CENTRAL AND NORTHERN IOWA. NOW THAT DAYTIME HEATING AND MIXING HAS SUBSIDED...AND GIVEN CONTINUED SOUTHWESTERLY FLOW AHEAD OF ARCTIC FRONT SUPPORTED BY SURFACE OBS AND PROFILER DATA...EXPECT STRATUS TO LIFT SLIGHTLY NORTHEAST ACROSS BOTH TAF SITES. THE NEXT ROUND OF MVFR STRATUS ARRIVES IN ASSOCIATION WITH ARCTIC FRONT...WHICH SHOULD CROSS KRST/KLSE AROUND OR SLIGHTLY AFTER 06Z TONIGHT. CEILINGS WILL LOWER TO BETWEEN 2 AND 3 KFT...ALONG WITH GUSTY NORTHWESTERLY WINDS. SCATTERED SNOW FLURRIES OR BRIEF SNOW SHOWERS ARE POSSIBLE OVERNIGHT THROUGH MUCH OF FRIDAY MORNING...BUT NO VISIBILITY RESTRICTIONS ARE ANTICIPATED. && .ARX WATCHES/WARNINGS/ADVISORIES... 215 PM CST THU FEB 9 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...TAYLOR