FXUS63 KFGF 260251
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
851 PM CST WED NOV 25 2009
.UPDATE...
MAIN ISSUE TONIGHT IS CLEARING AND TEMPS. SFC RIDGE AXIS IS
ALIGNED WITH THE BACKEDGE OF THE MAIN CLOUD DECK WHICH LIES FROM
EXTREME EASTERN SASK TO MINOT TO JUST WEST OF BISMARCK TO MOBRIDGE
SD. PAST EXPERIENCE SHOWS THIS BACKEDGE CLEARING AREA WILL
CONTINUE TO SLOWLY EDGE EAST AS SFC HIGH PRESSURE RIDGE MOVES
EAST. PROBLEM IS THIS IS NOT EXPECTED TO PASS THROUGH THE VALLEY
UNTIL 15Z OR SO ON THURSDAY AND NOT INTO NW MN UNTIL THURSDAY
AFTERNOON. MEANWHILE...SOME CLEARING HOLES CONTINUE TO EXPAND
SLOWLY SOUTHEAST FROM MANITOBA INTO NE ND...WITH THE BIGGEST ONE
FROM BRANDON MANITOBA TO ROLLA ND WITH OTHER MUCH SMALLER ONES
LOCATED ALONG THE WEST EDGE OF THE RED RIVER VALLEY. NW AND WCNTRL
MN SOCKED IN ATTM. MOISTURE IS TRAPPED PER BISMARCK SOUNDINGS AT
800 MB AND MODEL PROG FOR BISMARCK IS A BIT TOO WEAK ON THE
MOISTURE AND THUS THE TREND OF THE MODELS (GFS/NAM/CANADIAN) IS TO
PROG TOO QUICK OF A CLEARING TONIGHT. SO BACKED OFF ON FAST
EVOLUTION OF CLEARING BUT STILL WENT WITH THE BASIC IDEA OF
DECREASING CLOUDS THRU 12Z THU. DID NOT CHANGE TEMPS MUCH....MORE
CLOUDIER AREAS WILL SEE LOWER 20S BY MORNING WITH TEENS IN CLEARER
AREAS.
&&
.PREV DISCUSSION... /ISSUED 241 PM CST WED NOV 25 2009/
SHORT TERM [THIS EVENING - SAT]...
THE MAIN CHALLENGES IN THE SHORT TERM ARE DETERMINING THE STRENGTH
OF BREEZY WINDS THROUGH THIS EVENING...TEMPERATURES OVER THE NEXT
FEW DAYS...AND PCPN CHANCES SATURDAY WHEN A LOW PRESSURE SYSTEM
MOVES OUT OF THE CANADIAN/AMERICAN HIGH PLAINS INTO THE NORTHERN
PLAINS. THE MODELS ARE IN GOOD AGREEMENT THROUGH FRIDAY...BUT
STILL HAVE ENOUGH DIFFERENCES HANDLING THE SATURDAY SYSTEM. THE
LATEST RUNS OF THE GFS AND ECMWF ARE SIMILAR TO ITS PREVIOUS
RUNS...BUT THE GEM IS NOT. SINCE THE NAM HAS BEEN PRETTY GOOD THE
LAST COUPLE DAYS...CONTINUED HEAVY RELIANCE ON THE NAM THROUGH
FRIDAY...THEN TRANSITIONED TO A LEANING ON THE GFS AND ECMWF
SATURDAY.
A SLIGHT CHANCE OF SNOW SHOWERS WILL CONTINUE ACROSS WEST CENTRAL
MINNESOTA THROUGH THE REST OF THE AFTERNOON. BREEZY NORTHWEST
WINDS WILL CONTINUE THROUGH THIS AFTER AND SLOWLY SUBSIDE THIS
EVENING AS HIGH PRESSURE ADVANCES INTO THE NORTHERN PLAINS. THINK THE
CLOUDY SKIES ARE LIMITING THE POTENTIAL FOR IDEAL MIXING...SO GLAD
DID NOT GO TOO STRONG ON THE MORNING UPDATE. THE CLEARING SKIES
TONIGHT AND COLD TEMPERATURES AT 925 MB -4 TO -7 CELSIUS SHOULD
MAKE COLD OVERNIGHT LOWS IN THE TEENS...GIVING THANKSGIVING THE
HONOR OF HAVING THE COLDEST MORNING FOR THE NEXT SEVERAL DAYS.
A 500 MB RIDGE WILL BUILD OUT OF THE ROCKIES AND PROVIDE WARMER
TEMPERATURES THE NEXT COUPLE DAYS...PARTICULARLY FRIDAY.
OTHERWISE...EXPECT DRY WEATHER THURSDAY AND FRIDAY.
AN 500 MB TROUGH WILL DIG INTO THE ROCKIES FRIDAY NIGHT WITH LOW
SURFACE PRESSURE DEVELOPING ACROSS THE CENTRAL UNITED STATES. THE
MODELS INDICATE THE MAIN ENERGY WILL AFFECT THE SOUTH CENTRAL
US...BUT THAT ANOTHER LOW PRESSURE SYSTEM COULD DEVELOP SOME
PRECIPITATION OVER THE NORTHERN PLAINS THIS WEEKEND. THE OOZ RUNS
AND 06Z/12Z GFS INDICATED THE CANADIAN BORDER AREA AS HAVING THE
BEST CHANCE OF PCPN SATURDAY...WITH MOST PRECIPITATION FALLING
NORTH OF THE BORDER UNTIL SUNDAY. HOWEVER...THE 12Z GEM AND ECMWF
ARE CAME IN WITH MORE SOUTHERN SOLUTIONS. THEREFORE...SLIGHTLY
EXPANDED THE PCPN CHANCES SOUTHWARD ON SATURDAY...AND WE WILL
WATCH THE TREND IN THE MODELS TO SEE IF THE SOUTHERN SOLUTION
SEEMS MORE LIKELY.
LONG TERM [ SAT NIGHT - TUE]...
LONG RANGE MODELS OVERALL IN PRETTY GOOD AGREEMENT THROUGH THE
EXTENDED RANGE. COUPLE OF MID LEVEL WAVES TO IMPACT REGION EARLY AND
THEN LATE IN PERIOD. NEITHER OF WHICH LOOK PARTICULARLY STRONG WITH
BEST CONVERGENCE AND UPPER SUPPORT NORTH OF BORDER INITIALLY AND
EVENTUAL SPLITTING OF MID LEVEL FLOW LATE. WILL MAINTAIN LOW CHANCE
SNOW POPS. LACK OF SNOW COVER WILL HOLD TEMPERATURES CLOSE TO IF NOT
ABOVE AVERAGES.
AVIATION...
MVFR CIGS EXPECTED TO GRADUALLY SCATTER OUT FROM N-S OVERNIGHT AS
HIGH PRESSURE BUILDS INTO FA AND COLUMN DRIES. WINDS WILL ALSO
DIMINISH AFTER SUNSET.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/G2
