FXUS63 KFGF 070338
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
938 PM CST SUN DEC 6 2009
.DISCUSSION...
BROAD UPPER TROUGH WAS ACROSS THE US WITH SHORT WAVES OFF THE OR
COAST AND ANOTHER OVER IA/MO AREA. ALSO POSITIVE TILTED TROUGH AXIS
EXTENDING FROM NORTHERN MAN TO OFF THE OR COAST. RELATIVELY WEAK
SOUTHWEST FLOW ALOFT FORECAST FOR THE NORTHERN PLAINS THROUGH WED.
SURFACE RIDGE OVER ALTA WILL SLOWLY DRIVE COOLER WEATHER TO THE
NORTHERN PLAINS THROUGH MID WEEK. NAM APPEARS TO HAVE INITIALIZED
BETTER THAN THE GFS AND ECMWF. SO NAM WILL BE USED FOR TONIGHT.
NAM SOUNDINGS INDICATE WEAK COLD ADVECTION OCCURS OVER MUCH OF THE
FORECAST AREA OVERNIGHT WHILE LOW LEVEL MOISTURE TO INCREASE IN THE
EASTERN ZONES. NAM CROSS SECTION INDICATES SOME DRYING/COOLING OVER
THE NORTHWEST ZONES. WILL UPDATE ZONES.
&&
.PREVIOUS DISCUSSION.../ISSUED 304 PM CST SUN DEC 6 2009/
CONCERNS REMAIN CLOUD AND TEMP TRENDS THE NEXT FEW DAYS. UPPER LOW
OVER NORTHEAST ONTARIO AND THE DEVELOPING STORM SYSTEM OVER THE
CENTRAL PLAINS WILL KEEP THE FCST AREA IN THE 500 MB MEAN TROUGH
THROUGH TUESDAY WITH NORTHERLY FLOW SFC UP TO 250 MB. QUITE A BIT OF
MOISTURE IN THIS TROUGH WITH HIGHER LEVEL MOISTURE DROPPING
SOUTHWEST AROUND UPPER LOW AND QUITE A BIT OF LINGERING 850 MB
MOISTURE. CONVECTIVE TEMPS REMAIN LOW SO THAT ANY BREAKS THAT FORM
FILL IN WITH THIN STRATOCUMULUS. WOULD EXPECT SOME CHANCE THAT
CLEARING WILL TAKE PLACE TONIGHT IN SPOTS...BUT WHERE AND HOW LONG IS
NEARLY IMPOSSIBLE TO PREDICT MORE THAN A FEW HOURS OUT AT BEST.
CONSIDERING EXTENSIVE CLOUDINESS UPSTREAM INTO MANITOBA WILL
MAINTAIN GENERAL IDEA THRU MONDAY AT LEAST OF MOSTLY CLOUDY SKIES
AND FLURRIES. SFC HIGH TO BUILD A BIT MORE INTO ERN ND MON NIGHT AND
TUESDAY AND 850 MB PRESSURE DEFICIT PROGS INDICATE A BETTER CHC AT
MORE WIDESPREAD CLEARING MON NIGHT AND TUESDAY...ESP FROM 12Z GEM.
BUT UNCERTAINTY KEEPS ME FROM DROPPING LOWS TOO MUCH. LOW TEMPS
TONIGHT WILL BE DIFFICULT...AND AREAS THAT WILL CLEAR OUT FOR A TIME
WILL DROP TO 10 BELOW ZERO OR LOWER WHILE SOME SPOTS IN THICKER CLDS
WILL STAY IN THE 10-15 RANGE. KEPT THE MIDDLE OF THE ROAD APPROACH
WHICH WAS WHAT THE PREV FCSTS HAD WHICH ARE LOWS FOR SINGLE DIGITS
BELOW ZERO DVL BASIN TO SINGLE DIGITS ABOVE ELSEWHERE.
FOR TUES NIGHT INTO WEDNESDAY...WILL BE WATCH THE BIG STORM IMPACT
AREAS TO OUR SOUTH AND EAST. WILL MAINTAIN LOW POPS FOR NRN EDGE
OF LIGHT SNOW WHICH MAY IMPACT FAR SE ND AND PARTS OF WCNTRL-
NCNTRL MN. OTHERWISE WINDS WILL INCREASE A BIT ON WEDNESDAY AND
ENOUGH SUBSIDENCE MAY HELP PRODUCE CLEARING AS COLDER AIR ADVECTS
IN.
LONG TERM [THU-SUN]...
EXTENDED PERIOD CONTINUES TO LOOK VERY QUIET WEATHER WISE WITH THE
PERSISTENT TROUGH NEAR THE AREA SLOWLY SHIFTING OFF TO THE EAST.
HARD TO SAY THAT IT WILL BE ENTIRELY DRY AS THERE COULD BE SOME
FLURRIES HERE AND THERE...BUT IMPOSSIBLE TO PIN SOMETHING LIKE THAT
DOWN THIS FAR OUT. MAIN QUESTIONS LOOK TO REVOLVE AROUND TEMPS.
MODELS ARE WAFFLING A LITTLE ON THE POTENTIAL SLIGHT WARMING TREND
THAT HAD APPEARED BY SAT/SUN. 12Z RUNS OF THE GFS/CANADIAN ARE
TRENDING COOLER NOW WHILE THE 00Z RUN OF THE ECMWF WAS WARMER. JURY
STILL OUT ON HOW THAT WILL WORK OUT.
&&
.AVIATION...
SATELLITE LOOPS NOT OF MUCH HELP. HIGH CLOUDS WERE OBSCURING LOW
CLOUD DECK OVER SOUTHERN ZONES. LITTLE CONTRAST IN NORTHERN ZONES.
HOWEVER SURFACE OBS INDICATE MOSTLY MVFR CIGS WERE LOCATED OVER THE
SOUTHEAST FORECAST AREA WHILE MOSTLY VFR CIGS WERE LOCATED OVER THE
NORTHWEST FORECAST AREA. ALSO A CLEAR AREA WAS NOTED OVER NORTHWEST
ND MOVING SOUTHEAST ABOUT 15 KNOTS. CLEARING COULD REACH TOWNER
COUNTY ABOUT MIDNIGHT. WILL GO FOR CIGS RISING FROM THE NORTHWEST.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
HOPPES
