000 FXUS63 KFGF 250253 AFDFGF AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 853 PM CST TUE NOV 24 2009 .UPDATE... FOCUS ON CURRENT SYSTEM MOVING SOUTHEAST THRU CNTRL ND AND ASSOC SNOWFALL. FIRST OFF...ALL MODELS OVER ESTIMATING QPF GREATLY AS SATURATION IN THE LOWEST LEVELS PRETTY ANEMIC SO FAR. SFC MAP AT 02Z SHOWS SFC LOW NORTHWEST OF JAMESTOWN WITH 500 MB UPPER LOW MOVING INTO NORTH CENTRAL ND. ALONG AND SOUTH OF THE SFC LOW IS A BAND OF CONVECTIVE SHOWERS...RAIN AND SNOW...MOVING SOUTHEAST QUICKLY. AROUND THE UPPER LOW IS SOME LIGHT SNOW SHOWERS...BUT MINOT AND CANADIAN RADARS INDICATE SNOW BAND IS NOT SOLID WITH ONE BAND HAVING MOVED FROM YORTON SASK TO DAUPHIN MANITOBA AND OBS INDICATE SOME SCATTERED SNOW AROUND RUGBY-MINOT. NOTHING HAS HAPPENED SO FAR IN THE BRANDON AND SW MANITOBA AREA PER OBS AND WEBCAM. ENTIRE SYSTEM WILL CONTINUE TO DROP SOUTHEAST. GUSTY WINDS LOOK GOOD BEHIND LOW OVER CNTRL ND INTO SD ON WEST SIDE OF SFC LOW WITH MUCH LIGHTER WINDS NORTH OF SFC LOW OVER MAJORITY OF FCST AREA TONIGHT. RADAR AND OBS WOULD SHOW MAYBE 50 PCT OF RADAR RETURNS REACHING THE GROUND IN THE DVL-MINOT AREA TO BISMARCK AND MOVEMENT IS QUITE FAST. FELT SCATTERED SNOW SHOWERS WOULD DEAL WITH SITUATION THE BEST. ANY ACCUM WILL BE VERY MINOR WITH UPSTREAM WEBCAMS IN SASK SHOWING A COUPLE TENTHS. LOWEST VSBYS ARE ALONG BACKEDGE BAND SEEN IN MINOT RADAR NOW MOVING THRU MINOT AT 0252Z. ALSO TWEEKED BACK POPS SOME WEDNESDAY TO A SCT SNOW SHOWER SITUATION. && .PREV DISCUSSION... /ISSUED 237 PM CST TUE NOV 24 2009/ SHORT TERM... MAIN CHALLENGE IN THE SHORT TERM WILL BE SNOW CHANCES WITH THE WEAK CLIPPER SYSTEM FOR LATE TONIGHT INTO WED. MODELS IN DECENT AGREEMENT ON THE DETAILS...WHICH ALSO MATCH CONTINUITY WELL. TONIGHT...WATER VAPOR IMAGERY SHOWS THE NEXT UPPER LEVEL WAVE MOVING INTO SOUTHERN SASKATCHEWAN NOW. THERE DOES NOT APPEAR TO BE ONE NICE COMPACT PIECE OF VORTICITY...BUT SEVERAL SMALL PIECES. THIS WAVE IS FORECAST TO DROP DOWN INTO THE FA LATE TONIGHT INTO EARLY WEDNESDAY. THE SFC REFLECTION WILL BE A WEAK CLIPPER SYSTEM. LOOKING AT THE UPSTREAM METAR REPORTS...HAVE SEEN ONLY ONE STATION IN SOUTHWEST SASKATCHEWAN REPORTING ANY SNOW SO FAR. CANADIAN RADARS ALSO SHOW MINIMAL ACTIVITY TO THIS POINT. EVEN CEILINGS UP IN THIS AREA ARE FAIRLY HIGH...GENERALLY AROUND 6K FEET. THIS SYSTEM IS COMING FROM A RELATIVELY DRY AIR MASS...SO AM THINKING THAT MODEL QPF AMOUNTS MAY BE OVERDONE. SEVERAL UPSTREAM METARS ARE ALSO REPORTING VIRGA...MEANING THE LOW LAYERS ARE DRY. WILL DELAY THE ONSET OF ANY LIGHT SNOW UNTIL MID EVENING IN THE KDVL REGION...THEN SPREADING EASTWARD AFTER MIDNIGHT. SNOW CHANCES ARE LOOKING LOWEST FOR THE NORTHEAST FA NEAR THE LAKE OF THE WOODS REGION. FOR AREAS THAT DO SEE SOME SNOW...AMOUNTS LOOK TO BE A DUSTING FOR MOST AREAS. WIND SPEEDS WILL ALSO INCREASE TOWARDS MORNING...BUT DOUBT MUCH SNOW WILL ABLE TO BE LOFTED. WED-FRI...MOST OF THE LINGERING SNOW SHOULD MOVE INTO WEST CENTRAL MN ON WED MORNING WITH POSSIBLY FLURRIES OR VERY LIGHT SNOW STILL LINGERING THRU THE NORTHERN VALLEY. KEPT IN SOME LIGHT SNOW IN THE FAR EASTERN FA THROUGH WED EVENING...BUT WOULD NOT BE SURPRISED TO SEE IT END EVEN FASTER. TEMPS ON WED WILL PROBABLY RISE LITTLE IF AT ALL. THANKSGIVING DAY LOOKS MUCH LIGHTER WIND WISE ALTHOUGH TEMPS WILL STAY CHILLY. LOOKING AT SOME REBOUND IN TEMPS BY FRI. LONG TERM [FRI NIGHT-MON]... THE MAIN CHALLENGES IN THE LONG TERM INCLUDE DETERMINING PCPN CHANCES ASSOCIATED WITH A LONGWAVE TROUGH THAT WILL CROSS THE CENTRAL UNITED STATES THIS WEEKEND INTO EARLY NEXT WEEK...AS WELL AS TEMPERATURES EARLY NEXT WEEK. THE MODELS HAVE SIGNIFICANT DIFFERENCES...BUT ALL POINT TO A CLIPPER SYSTEM THAT COULD BRING PRECIPITATION TO THE NORTHERN PLAINS SATURDAY INTO SUNDAY. LEANED ON THE ECMWF AND GFS FOR THIS FORECAST DUE TO THEIR RUN TO RUN CONSISTENCY. ALL THE MODELS INDICATE THE DEVELOPMENT OF SURFACE LOW PRESSURE OVER THE AMERICAN OR CANADIAN HIGH PLAINS FRIDAY NIGHT AS THE MAIN UPPER LEVEL TROUGH CROSSES OVER THE ROCKIES. THE SURFACE LOW PRESSURE SYSTEM COULD ACT AS A CLIPPER AND BRING SOME PRECIPITATION TO THE NORTHERN PLAINS SATURDAY INTO SUNDAY. THE GFS IS THE MOST ROBUST MODEL FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA BECAUSE IT TAKES A MIDDLE OF THE ROAD PATH WITH LOW PRESSURE CENTER...SOUTH DAKOTA TO UPPER PENINSULA MICHIGAN. THE GEM IS SOUTHERN SOLUTION...SASKATCHEWAN TO SOUTHERN WISCONSIN...AND INDICATES MOST OF THE PRECIPITATION FALLING IN SOUTH DAKOTA. THE ECMWF IS THE NORTHERN SOLUTION...SASKATCHEWAN TO ONTARIO...AND INDICATES MOST OF THE PRECIPITATION WILL FALL NORTH OF THE CANADIAN/AMERICAN BORDER. DESPITE THESE DIFFERENCES...ONE CANNOT RULE OUT PRECIPITATION FOR THIS NECK OF THE WOODS UNTIL THE MODELS GET A BETTER HANDLE ON THE APPROACHING SYSTEM. ANY PRECIPITATION SHOULD BE COLD ENOUGH TO BE A MIX OF RAIN AND SNOW...IF NOT SNOW ALL TOGETHER. IT LOOKS LIKE A COLD AND MORE SEASONABLE AIR MASS WILL FOLLOW UP THE PASSING SYSTEM EARLY NEXT WEEK. AVIATION... EXPECT VFR CIGS AND VSBYS THROUGH THE REST OF THE EVENING. SNOW IS EXPECTED TO MOVE INTO THE REGION TONIGHT...BEGINNING WITH DVL NEAR MIDNIGHT. THE SNOW WILL THEN SPREAD INTO THE VALLEY EARLY TOMORROW MORNING...AND THEN TVF AND BJI NEAR DAWN. EXPECT MVFR OR LOW VFR VSBYS WITH THE PASSING OF THE SNOW THROUGH TOMORROW MORNING AS NORTHWEST WINDS INCREASE AND BECOME GUSTY. MVFR CIGS ARE LIKELY WITH THE PASSING SYSTEM...BUT WOULD NOT BE SURPRISED TO SEE IFR TOO. THE NORTHWEST WINDS SHOULD INCREASE TO 15 TO 20 KNOTS WITH GUSTS TO 25 KNOTS BY TOMORROW AFTERNOON. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE/GODON