RSS FeedsIssued by NWS Aberdeen, SD
000 FXUS63 KABR 250231 AFDABR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 831 PM CST TUE NOV 24 2009 .UPDATE... CLOUDS INCREASING ACROSS THE CWA THIS EVENING ALONG WITH RADAR ECHOES. ALTHOUGH...WITH IT BEING PRETTY DRY IN THE LOWER LEVELS DONT EXPECT MUCH PRECIPITATION TO MAKE IT TO THE GROUND ACROSS CENTRAL AND NORTH CENTRAL SD. NORTHEAST SD AND WEST CENTRAL MN WILL HAVE THE BEST CHANCES FOR SNOWFALL LATER TONIGHT AND EARLY WEDNESDAY. THE CURRENT WEATHER AND POP GRIDS LOOK FINE. ALSO...NORTHWEST WINDS WERE INCREASING ACROSS CENTRAL AND NORTH CENTRAL SD THIS EVENING AND THIS WILL CONTINUE TO SPREAD EAST THROUGH THE NIGHT. CURRENT FORECAST LOOKS FINE. && .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT MAIN FORECAST CHALLENGE IN THE NEAR TERM IS THE POTENTIAL FOR SNOW SHOWERS TONIGHT AND WEDNESDAY. AN UPPER LEVEL TROUGH WILL BE JUST EAST OF THE REGION THIS EVENING...WITH ANOTHER APPROACHING FROM THE NORTH. THE NORTHERN WAVE WILL DROP OVER THE NORTHERN PLAINS OVERNIGHT...BECOMING CENTERED OVER THE EASTERN DAKOTAS BY MORNING. THIS TROUGH PUSHES EAST OF THE REGION ON WEDNESDAY...WITH THE BACK EDGE OF THE PVA REMAINING OVER EASTERN SOUTH DAKOTA. THE TROUGH CONTINUES EAST WEDNESDAY NIGHT...WITH THE NORTHERN PLAINS BECOMING SITUATED BETWEEN IT AND A RIDGE WEST OF THE ROCKIES...WITH NORTHWEST FLOW OVER THE CWA. THIS FLOW CONTINUES INTO THURSDAY AS THE RIDGE SLIDES OVER THE ROCKIES...EVENTUALLY REACHING THE WESTERN PLAINS THURSDAY NIGHT. AT THE SURFACE...BROAD LOW PRESSURE WILL EXTEND FROM MANITOBA TO ILLINOIS TONIGHT...WITH HIGH PRESSURE EXTENDING FROM THE PACIFIC NORTHWEST TO TEXAS. A WEAK CLIPPER LOW ON THE WEST SIDE OF THE BROADER LOW WILL DROP OVER THE EASTERN DAKOTAS TONIGHT AND WEDNESDAY. MODELS IN GOOD AGREEMENT THAT PRECIPITATION WILL ACCOMPANY THE WEAK CLIPPER...MAINLY IN THE FORM OF SNOW SHOWERS AS TEMPERATURES COOL FROM THE MID LEVELS DOWN TO THE SURFACE. THE CENTRAL AND EASTERN CWA WILL SEE THE BEST CHANCE FOR THE SNOW SHOWERS...ESPECIALLY LATE TONIGHT AND WEDNESDAY MORNING. HIGH PRESSURE SLIDES OVER THE PLAINS WEDNESDAY NIGHT BEHIND THE EXITING LOW PRESSURE SYSTEM...THEN CONTINUES EAST AS A TROUGH DIGS DOWN THE LEE OF THE ROCKIES. THIS TROUGH BEGINS TO MOVE OVER THE PLAINS THURSDAY NIGHT...BUT LOOKS TO MOVE THROUGH DRY. TEMPERATURES WILL BE A GOOD 10 DEGREES OR SO COOLER ON WEDNESDAY COMPARED TO TODAYS TEMPS AS H85 TEMPS DROP INTO THE SINGLE DIGITS BELOW ZERO WITH THE CLIPPER. WILL SEE THEM REBOUND ON THURSDAY AS WAA REDEVELOPS. H85 TEMPS CLIMB BACK ABOVE ZERO...EVEN APPROACHING +10 ACROSS THE FAR WESTERN CWA. .LONG TERM...FRIDAY THROUGH TUESDAY MODELS ARE IN FAIR AGREEMENT ON THE EXTENDED TIME FRAME. SOME DIFFERENCES POP UP LATER IN THE PERIOD BUT IT APPEARS AT THIS TIME THEY WILL NOT HAVE A BIG AFFECT ON THE FINAL PRODUCT. THE PERIOD OPENS WITH A MINOR WEST COAST TROUGH AND AN UPPER LEVEL RIDGE OVER THE MIDWEST. AS THE WESTERN UPPER LEVEL TROUGH STARTS MOVING EAST THERE WILL BE A LEE SIDE TROUGH FORM AT THE SURFACE. BY THE WEEK END THIS SYSTEM IS OVER THIS AREA. HAVE KEPT THE SLIGHT CHANCE CATEGORY SNOW SHOWERS FOR SATURDAY EVENING AND SUNDAY. THIS IS GOING WITH A MORE PROGRESSIVE GFS SOLUTION. THE ECMWF CURRENTLY DIGS THE SOUTHERN END OF THE TROUGH INTO A CLOSED LOW ALOFT OVER THE FOUR CORNERS AREA. IF THIS SOLUTION WERE TO VERIFY THE TIMING OF THE PRECIPITATION WOULD BE ABOUT 24 HOURS SLOWER. FOR NOW HAVE GONE WITH CONTINUITY AND WILL WAIT FOR THE MODELS TO SORT OUT THE TIMING. EXPECT THE FINAL SOLUTION WILL BE BETWEEN THE TWO. THE ECMWF SOLUTION HAS THE LOOK OF A MAJOR WINTER STORM EXCEPT THERE IS NO GOOD SURFACE REFLECTION UNTIL TUESDAY AND THEN TOO FAR EAST. AFTER THIS SYSTEM HAS PASSED THE UPPER LEVEL RIDGE REFORMS UNTIL EARLY TUESDAY WHEN ANOTHER UPPER LEVEL LOW ROTATING AROUND A POLAR VORTEX MOVES INTO THE REGION. AT THIS TIME IT APPEARS THAT THIS SYSTEM WILL BE FARTHER EAST THAN WOULD BE NEEDED TO BRING MUCH WEATHER THROUGH THIS AREA. && .AVIATION... LOWERING CEILINGS...INCREASING WINDS ALONG WITH SCATTERED SNOW SHOWERS DEVELOPING THROUGH THE NIGHT AND WEDNESDAY. THE MID AND HIGH LEVEL CLOUDS OVER ALL OF THE TAF SITES WILL LOWER THROUGH THE NIGHT INTO THE MVFR/LOW VFR RANGE AS LIFT AND CAA INCREASES AS A CLIPPER SYSTEM DROPS IN FROM THE NORTHWEST. ECHOES ON THE RADAR WILL INCREASE AND EXPECT ALL SITES TO RECEIVE A RAIN OR SNOW SHOWER THROUGH THE NIGHT. ATY WILL BE THE MOST LIKELY TO RECEIVE SNOW SHOWERS ALONG WITH VISIBILITIES DROPPING TO A MILE OR LESS LATER TONIGHT AND EARLY WEDNESDAY. OTHERWISE...NORTHWEST WINDS WILL INCREASE AT ALL SITES BY MORNING AND IT WILL BE WINDY AT ALL SITES THROUGH THE DAY WEDNESDAY WITH CAA AND MIXING. ALONG WITH THE WINDS WILL BE MVFR/VFR CEILINGS IN THE 2000-4000 FOOT RANGE WITH SCATTERED SNOW SHOWERS POSSIBLY AFFECTING ATY AND ABR. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...MOHR SHORT TERM...PARKIN LONG TERM...KEEFE AVIATION...MOHR WEATHER.GOV/ABERDEEN
