000 FXUS63 KDVN 100554 AFDDVN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 1154 PM CST THU FEB 9 2012 .AVIATION... STRATUS WITH VFR TO MVFR CIGS WILL PERSIST THROUGH THU AM. ARCTIC FRONT TO PASS THROUGH TERMINALS BETWEEN ROUGHLY 10Z-14Z. W/SW WINDS AROUND 10 KTS AHEAD OF FRONT WILL SHIFT TO NW AND BECOME GUSTY AT 15-30 KTS WITH FRONTAL PASSAGE. MAY BE BRIEF WINDOW OF PARTIAL CLEARING PRIOR TO FROPA ESPECIALLY AT KCID... AND SOME LIGHT FOG WITH 3-5SM VSBY POSSIBLE. OTRW... CIGS MORE WIDESPREAD MVFR THU AM AS MUCH COLDER AIR OVERTAKES REGION. FLURRIES WILL LIKELY BE WRUNG OUT WITH THE COLD ADVECTION WITH FEW SHSN POSSIBLE BY MID AM THROUGH EARLY AFTN AS ATMOSPHERE BECOMES MORE UNSTABLE. MODELS WANT TO KEEP A LOT OF LOW LEVEL MOISTURE AROUND THU NGT BUT SATL AND OBS POST FRONTAL SHOW LOW CLOUDS NOT LASTING MORE THAN ABOUT 4-6 HRS OR SO AFTER FROPA BEFORE SCOURING OUT WITH STRONG SUBSIDENCE. THEREFORE.. CONTINUED TRENDS OF DECREASING LOW CLOUDS DURING AFTN THROUGH SUNSET. WINDS TO REMAIN GUSTY 15-20+ KTS THU NGT. && .PREV DISCUSSION... /ISSUED 305 PM CST THU FEB 9 2012/ SYNOPSIS... 12Z UA ANALYSIS HAS SEVERAL SHORTWAVE TROFS FROM THE GREAT LAKES BACK INTO THE PLAINS. AN 850MB COLD FRONT RAN FROM CANADIAN UA SITE CYEG IN ALBERTA PROVINCE TO THE SOUTH EDGE OF JAMES BAY. SATELLITE TRENDS THROUGH MID AFTERNOON SHOW THE LOW CLOUDS MOVING EAST ACROSS THE AREA WITH CLEARING ACROSS SOUTHERN MINNESOTA AND WISCONSIN. THE LOW POST FRONTAL CLOUDS OF THE ARCTIC FRONT WERE ACROSS NORTH DAKOTA AND NORTHERN MINNESOTA. 18Z SFC ANALYSIS HAD A RIDGE RUNNING FROM THE LOWER MISSISSIPPI VALLEY INTO THE OHIO VALLEY. THE ARCTIC FRONT RAN FROM EASTERN MONTANA INTO NORTHWEST MINNESOTA. DEW POINTS ACROSS THE MIDWEST WERE GENERALLY IN THE TEENS AND 20S WITH 30S IN THE SOUTHERN PLAINS AND EASTERN KANSAS. SHORT TERM...TONIGHT AND FRIDAY... THE SHALLOW NATURE OF THE CLOUDS...ROUGHLY 1-2KFT...IS ONE OF MANY REASONS WHY THE MODELS ARE DOING AN EXTREMELY POOR JOB OF DEPICTING THEM AND HANDLING THEIR OVERALL MOVEMENT. THESE CLOUDS PLAY SIGNIFICANTLY INTO SENSIBLE WX TRENDS TONIGHT BEFORE THE ARCTIC FRONT ARRIVES. THE RUC AND WRF HAVE A VAGUE IDEA ABOUT THE CLOUDS AND EITHER THE 0.5-1KM LAYER OR 0.5KM LAYER IS AT LEAST HINTING AT THE CLOUDS. USING THIS ALONG WITH EXTRAPOLATION FROM CURRENT SATELLITE TRENDS RESULTS IN CLOUDY SKIES FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING HOURS. BASED ON THE CURRENT CLEAR AREA TO THE NORTH AND WHAT THE MODELS ARE SUGGESTING...THE CLOUDS SHOULD PARTIALLY BREAK UP ACROSS THE NORTHERN THIRD OF THE CWFA LATE THIS EVENING. WHAT PARTIAL CLEARING THAT DEVELOPS WILL BE FORCED SOUTH AFTER MIDNIGHT AS THE ARCTIC FRONT STARTS MOVING INTO THE CWFA. BECAUSE OF THE CLOUDS...TEMPERATURES WILL BE WARMER THAN LAST NIGHT. ANY AREAS THAT DO SEE PARTIAL OR A TOTAL CLEARING SHOULD DROP AND THEN REBOUND AS THE POST FRONTAL CLOUDS OF THE ARCTIC FRONT ARRIVE. THE CAA BEHIND THE ARCTIC FRONT IS IMPRESSIVE. LOW TEMPERATURES TONIGHT WILL LIKELY OCCUR 7-8 AM FRIDAY MORNING. ON FRIDAY...THE ARCTIC FRONT WILL CLEAR THE CWFA BY MID TO LATE MORNING WITH POST FRONTAL STRATUS CLOUDS FOLLOWING BEHIND IT. THE COMBINATION OF CAA...STRONG CYCLONIC FLOW ALOFT...A STRONG VORT MAX...STEEPENING LOW LEVEL LAPSE RATES...AND THE STRONGER FEBRUARY SUN ALL POINT TO SNOW SHOWERS DEVELOPING FROM LATE MORNING THROUGH THE AFTERNOON. FCST SOUNDINGS DO SHOW SOME SMALL CAPE DEVELOPING AS LAPSE RATES STEEPEN. PRIOR TO THE SNOW SHOWERS DEVELOPING THERE ARE REASONABLY LOW CONDENSATION PRESSURE DEFICITS WITH SOME FORCING AND F VECTOR CONVERGENCE. THUS FLURRIES MAY BE POSSIBLE WITH THE POST FRONTAL STRATUS BEFORE THE SNOW SHOWERS DEVELOP. SNOW AMOUNTS WITH THE SNOW SHOWERS WILL BE VARIED. AMOUNTS COULD RANGE FROM ONLY A TRACE TO AROUND ONE HALF INCH IN THE STRONGER SHOWERS. WINDS WILL BE QUITE BRISK ON FRIDAY AND MAY BE LOCALLY STRONGER AROUND SNOW SHOWERS. MAX TEMPERATURES FRIDAY WILL LIKELY OCCUR 9-11 AM WITH TEMPERATURES EITHER STEADY OR SLOWLY FALLING DURING THE AFTERNOON. ..08.. LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY... SEASONALLY COLD...A LIGHT SNOW EVENT MONDAY WITH A MODEST WARMING TREND INTO MIDDLE OF NEXT WEEK. OVERALL...LARGE SCALE FEATURES REASONABLE BUT LOW LEVEL BL PROBLEMS CONTINUE WITH MOST SOLUTIONS T/TD PROFILES LOWEST 2K AGL STILL OFF. MAIN CONTRIBUTOR IS OUR UNSEASONABLY LOW AMOUNTS OF SNOW NOT HANDLED BY PHYSICS PACKAGES. THIS IS RESULTING IN BL FORECASTS...ESPECIALLY AMERICAN SOLUTIONS EITHER TOO MOIST OR TOO DRY. INITIALIZATION AND VERIFICATION AGAIN SUGGESTS A HIGHER WEIGHT BE GIVEN TO COLDEST GUIDANCE FOR MIN TEMPERATURES WITH ARCTIC AIR IF NOT A FEW DEGREES COLDER. FOR HIGHS...ON THE WARM END FOR MAX TEMPS INTO MONDAY. TEXTBOOK WIDESPREAD LIGHT SNOW EVENT MONDAY WITH LOCAL TOOLS SUGGESTING .5 TO 1.5 INCHES OF SNOW MOST LOCATIONS AT THIS TIME. NEXT 24 HOURS...FINER DETAILS MAY SUGGEST A LEAD VORT MAX...THEN SOME ISOLATED 2 TO 3 INCHES NOT OUT OF THE QUESTION...THIS SHOULD BE KNOWN THIS TIME TOMORROW. FRIDAY NIGHT...CLEARING WITH STRONG CAA WITH NW WINDS 10-20+ MPH IN THE EVENING DECREASING TO 5-10 MPH OVERNIGHT. LOCAL TECHNIQUES SUPPORT 0-5F ABOVE NW 1/2 AND 5-10F ABOVE SE 1/2. WHEN ADJUSTING FOR BL PROBLEMS...POSSIBLE MINS MAY STILL BE 2-5 DEGREES TOO MILD FOR MANY IF NOT MOST LOCATIONS FOR LATER SIFTS TO REASSESS. SATURDAY AND SUNDAY...FAIR AND COLD WITH HIGHS UPPER TEENS TO MID 20S BOTH DAYS AND LOWS SUNDAY AM IN THE SINGLE DIGITS WITH SOME BELOW ZERO READINGS AGAIN POSSIBLE NW SECTIONS. SUNDAY NIGHT...INCREASING CLOUDS LATE WITH MINS IN THE TEENS WITH SLOWLY RISING TEMPERATURES POSSIBLE AFTER MIDNIGHT. MONDAY... UPPED POPS TO LOW END LIKELY TO HIGH END CHANCE WITH AREAS OF LIGHT SNOW TO OVERSPREAD AREA THROUGH MONDAY NIGHT. LOCAL TOOLS SUGGEST MOSTLY .5-1.5 INCHES ATTM WITH RISK OF SOME ISOLATED HIGHER AMOUNTS OF 2-3 INCHES POSSIBLE IF LEAD VORT MAX IS STRONGER. BL ISSUES MAKE THIS A CHALLENGE THAT LATER SHIFTS WILL NEED TO STAY ON TOP OF. HIGHS NEAR FREEZING WITH SOUTH WINDS LIMITING ACCUMULATIONS ON THE MOST TRAVELED ROADS. MONDAY...LIGHT SNOW TO DIMINISH TO FLURRIES OR END BY LATE OVERNIGHT HOURS. WITH MINOR ACCUMULATIONS IN THE FAR EAST UNTIL MIDNIGHT. LOWS WITH CLEARING IN THE NW SECTIONS MAY NEED TO BE TRIMMED FURTHER BY 2 TO 5 DEGREES. TUESDAY THROUGH THURSDAY...DRY TO MOSTLY DRY WITH LOW CHANCE POPS ON WEDNESDAY AND THURSDAY...MOSTLY LOWER SOUTH SECTIONS. MAIN FORCING IS SUGGESTED TO PASS TO THE SOUTH SO ANY AMOUNTS TO BE LIGHT IF NOT DRY. LATER SHIFTS MAY BE ABLE TO REMOVE POPS MANY LOCATIONS THE NEXT FEW DAYS. TEMPERATURES OVERALL TO TREND NEAR TO SLIGHTLY ABOVE NORMAL. ..NICHOLS.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$