749 FXUS63 KPAH 312139 AFDPAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 339 PM CST THU JAN 31 2013 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 315 PM CST THU JAN 31 2013 A STRONG ARCTIC FRONT IS COMBINING WITH AN UPPER LEVEL IMPULSE SHOOTING QUICKLY EASTWARD TOWARDS THE REGION TO PRODUCE BANDS OF LOCALLY HEAVY SNOWS ACROSS MISSOURI THIS AFTERNOON. MESO MODELS...ESP THE RUC...AS WELL THE 12Z GFS TO A LESSER EXTENT ARE CATCHING ONTO THIS. THE RUC BRINGS THE BANDING PRECIP...WHICH MAY BEGIN BRIEFLY AS LIGHT RAIN...INTO SOUTHEAST MISSOURI AND SOUTHERN ILLINOIS DURING THE MID TO LATE AFTERNOON HOURS IN THE POST FRONTAL ENVIRONMENT. THIS SNOW COULD QUICKLY BECOME HEAVY AT TIMES IN E TO W ORIENTED BANDS ACROSS THE REGION. THIS AREA OF PRECIPITATION WILL RAPIDLY MOVE EAST INTO ACROSS THE REMAINDER OF THE REGION EARLY TONIGHT. THE SNOW WILL LIKELY TAPER OFF JUST AS QUICKLY AS IT BEGAN OVER SOUTHEAST MISSOURI EARLY TONIGHT...THEN END OVER THE REST OF THE REGION BY AROUND MIDNIGHT AS THE IMPULSE TRAVELS OFF TO THE EAST ON THE NORTH SIDE OF THE COLD FRONT. THE MAIN IMPACT WILL COME WITH BURSTS OF LOCALLY HEAVY SNOW IN EAST TO WEST BANDING PRECIPITATION. WHERE...AND HOW NARROW OR THICK THESE BANDS OF SNOW BECOME WILL DETERMINE HOW MUCH SNOW A GIVEN LOCATION RECEIVES. AT THIS TIME...IT SEEMS LIKE MUCH OF THE ADVISORY AREA WILL SEE UP TO A QUICK INCH OR SO OF SNOW. HOWEVER...THERE WILL LIKELY BE LOCALLY HEAVIER BANDS THAT PRODUCE A QUICK 2 TO 3 INCHES OF SNOW. MOTORISTS SHOULD BE PREPARED FOR RAPIDLY FLUCTUATING VISIBILITIES TO UNDER A QUARTER MILE AT TIMES. OTHER IMPACTS INCLUDE THE FACT THAT MUCH OF THE SNOW WILL OCCUR DURING INCREASED TRAFFIC BETWEEN 4 PM AND 7 PM...ESPECIALLY IN SOUTHEAST MISSOURI...SOUTHERN ILLINOIS AND THE WESTERN TIP OF KENTUCKY AND SOUTHWEST INDIANA. TRUE ARCTIC BLAST...THOUGH FAIRLY BRIEF...WILL FOLLOW QUICKLY IN THE WAKE OF THIS SYSTEM. SHOULD SEE TEMPS STAY BELOW FREEZING ALL DAY FRIDAY...WELL BELOW FREEZING IF WE GET A FRESH LAYER OF SNOWFALL. SAME WITH FRI NIGHT. IF ANY SNOW IS ON THE GROUND...TEMPS WILL LIKELY CHALLENGE SINGLE DIGITS IN THOSE LOCATIONS. WEAK DISTURBANCE AND WARM FRONT WILL LIKE PASS NEAR THE REGION SAT. RIGHT NOW LOOKS LIKE A NON EVENT...UNLESS THE VERY LIGHT PRECIP BEGINS EARLY ENOUGH SAT AM. IF SO...THEN A LITTLE LIGHT SNOW...SLEET OF FREEZING RAIN WOULD BE POSSIBLE BEFORE SFC TEMPS WARM ABOVE FREEZING. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 315 PM CST THU JAN 31 2013 A FAIRLY ACTIVE PATTERN SETTING UP FOR NEXT WEEK...WITH SEVERAL WEATHER SYSTEMS TO KEEP AN EYE ON. HOWEVER...THEY ARE WEAK SYSTEMS...EXCEPT FOR THE ONE SLATED FOR WED NIGHT/THURSDAY...WHICH HAS THE BEST POTENTIAL RIGHT NOW OF BRINGING MORE WIDESPREAD PRECIPITATION. ON SUNDAY...WE SHOULD SEE SFC HIGH PRESSURE SLOWLY OOZE INTO THE REGION...WITH NORTHWEST FLOW ALOFT. MODELS DIVERGE AFTER THIS...AS THE 00Z ECMWF SHOVES THE SFC HIGH EAST SUNDAY NIGHT AS ANOTHER FRONTAL SYSTEM BARRELS DOWN FROM THE NORTHWEST. A WEAK WAVE ALOFT ACCOMPANIES THIS FEATURE BUT MOST OF THE ENERGY STAYS TO OUR SOUTHWEST. THE 06Z ECMWF SHOWED A GLANCING SHOT FOR PRECIP ACROSS SE MO/SW KY ON MONDAY...BUT THE 12Z RUN IS MUCH MORE AGGRESSIVE AND PAINTS QPF OVER THE ENTIRE AREA. THE GFS IS MUCH SLOWER WITH THE PROGRESSION OF THIS SYSTEM WITH ITS 06Z RUN...AND SHOWS THE SFC HIGH RETREATING MONDAY MORNING WITH THE FRONTAL SYSTEM APPROACHING LATER IN THE DAY...BUT WEAKENING SO MUCH THAT IT REALLY HAS LITTLE IMPACT ON OUR AREA. THE 12Z GFS RUN IS MORE IN LINE WITH THE TIMING OF THE 00Z ECMWF NOW...BUT STILL SPLITS OUR AREA WHEN IT COMES TO RAIN CHANCES...WITH THE MAIN PRECIP SKIRTING BY TO OUR NORTH AND SOUTH. WILL START OUT WITH A SLIGHT CHANCE ACROSS SOUTHERN MO AND SW KY. ANOTHER LOW PRESSURE SYSTEM COMES DOWN OUT OF THE NORTHERN PLAINS AND INTO THE MIDWEST LATE MONDAY NIGHT AND INTO TUESDAY. AGAIN...MODELS DO NOT AGREE ON THIS SYSTEM EITHER...WITH THE ECMWF MUCH DEEPER WITH THE UPPER TROUGH AND HENCE...IT INDICATES THAT SOME PRECIP CHANCES MAY FLIRT WITH THE WABASH VALLEY OF SE IL AND THE EVV TRI STATE REGION ON TUESDAY. SO EITHER WAY...IT DOES NOT LOOK LIKE TOO BIG A DEAL SINCE MOST OF THE MOISTURE STAYS FURTHER NORTH AND EAST OF THE AREA. MODEL SOUNDINGS INDICATE THAT THE LOWEST FEW THOUSAND FT WILL BE WARM ENOUGH THAT EVEN IF IT DID PRECIPITATE...IT SHOULD BE LIQUID. BUT THERE IS QUITE A DIFFERENCE IN LOW LEVEL TEMPS BTWN THE GFS AND ECWMF DUE TO THE DEGREE OF THE AMPLITUDE OF THE TROUGH COMING THROUGH. TUESDAY NIGHT AND WEDNESDAY...HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT...BUT WILL QUICKLY MOVE EAST WED NIGHT. OUR NEXT SYSTEM COULD IMPACT US AS EARLY AS LATE WED...OR HOLD OFF UNTIL THURSDAY. HOWEVER...THE SIGNAL IS FAIRLY STRONG THAT WE WILL SEE SOME PRECIPITATION ON THURSDAY...WITH SUPPORT OF THE GFS ENSEMBLES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1122 AM CST THU JAN 31 2013 BKN VFR DECK AT KEVV/KOWB ALONG WITH SOME MID CLOUDS AROUND. SCT TO MID CLOUDS POSSIBLE ELSEWHERE AS WELL. ARCTIC COLD FRONT OFF TO THE NORTHWEST WILL MOVE INTO THE AREA LATER THIS AFTERNOON. GUSTY WSW WINDS AHEAD OF IT. HAVE A -SN CHANCE FROM 21Z- 01Z WITH THE FRONTAL PASSAGE. CLEARING AFTER THAT...WITH GUSTY NW WINDS POST FRONTAL...WHICH WILL SLACKEN BY 12Z. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR ILZ081>094. MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MOZ076- 086-087-100-107>112-114. IN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR INZ081- 082-085>088. KY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR KYZ001>022. && $$ SHORT TERM...MEFFERT LONG TERM....CW AVIATION...CW