FXUS63 KFGF 251533
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
933 AM CST FRI DEC 25 2009
.DISCUSSION...
THE CURRENT FORECAST REMAINS ON TRACK FOR THE VALLEY BLIZZARD AND
MAJOR WINTER CHRISTMAS STORM FOR THE REGION. BAND OF MODERATE TO
HEAVY SNOW CONTINUE TO ADVECT IN FROM THE EAST...AND THIS WILL
CONTINUE THROUGH THE NEXT 24 HOURS. THE TROWAL ALOFT AND MOISTURE
FETCH FROM THE GULF WILL BE STRONGEST THROUGH 00Z SAT...BEFORE
SLOWLY WEAKENING OVERNIGHT. MOST VSBYS IN OPEN COUNTRY ARE BETWEEN
1/4SM TO AROUND 300FT IN SOME AREAS NEAR STARKWEATHER...WITH VSBY
IN TOWNS NOT TOO BAD. THIS WILL BE AN OPEN COUNTRY BLIZZARD...BUT
SIGNIFICANT DRIFTS WILL BE A PROBLEM IN ALL AREAS. SNOW RATES
AROUND NEAR AN INCH PER HOUR AT TIMES NEAR HEAVY SNOW BANDS...BUT
MEASURING SNOW IS TRICKY GIVEN WIND GUSTING OVER 30 MPH IN THE
VALLEY. WINDS MAY INCREASE A LITTLE TODAY IN THE VALLEY WITH THE
PRESSURE GRADIENT TIGHTENING AND ABOUT 35KT TO MIX FROM 925MB.
WITH ALL THIS SAID...NO CHANGES PLANNED AT ALL TO CURRENT
HEADLINES. TRUE BLIZZARD CONDITIONS MAY NOT BE MET IN GRANT AND
WESTERN OTTERTAIL COUNTIES...BUT GIVEN THE HEAVY SNOW AND IMPACTS
WON/T CANCEL IT TO CONFUSE PEOPLE.
WE WILL SEND AN UPDATED WSW OUT WITHIN THE HOUR TO FRESHEN IT UP.
&&
.AVIATION...
FOR MOST SITES EXPECT IFR CONDITIONS THRU THE DAY...EITHER DUE TO
VSBY IN SNOW AND BLOWING SNOW OR LOW CIGS. EXCEPTION WILL BE
BEMIDJI WHERE LESS BLOWING SNOW WILL MEAN VSBYS WILL AT TIMES BE
IN THE MVFR RANGE. WINDS WILL GUST TO 30 KTS OR MORE AT
GFK/FAR/DVL ESP MID MORNING THRU THE AFTN.
&&
.PREV DISCUSSION... /ISSUED 356 AM CST FRI DEC 25 2009/
SHORT TERM...
NO CHANGES TO HEADLINES WILL BE MADE. WILL KEEP BLIZZARD WARNING
AS IS FOR THE RED RIVER VALLEY AND POINTS WEST. WILL IT BE AN ALL
OUT WHITEOUT BLIZZARD...IN RURAL AREAS MOST LIKELY. IN CITIES AND
SHELTERED AREAS...CLOSE...BUT MIGHT NOT MAKE IT.
OVERALL THE FCST IS GOING EXCELLENT AND CURRENT TRENDS ON RADAR
AND SFC OBS CONFIRM PREV FCST THINKING. BANDS OF HEAVIER SNOW NOW
MOVING INTO THE VALLEY WITH MORE BANDS UPSTREAM IN CNTRL MN THAT
WILL MOVE OUR WAY. ECMWF/GFS MODELS WHICH HAVE DONE VERY WELL IN
THIS EVENT CONTINUE TO POINT TO AN EXTENDED PERIOD OF STRONG
ISENTROPIC LIFT 12Z FRI UNTIL ABOUT 06Z SAT. ALL MODEL QPF FCSTS
PAINT THE HIGHEST QPF IN THE VALLEY THRU 00Z AND THEN SHIFT IT
WEST A BIT TONIGHT. SO FAR SNOW TO LIQUID RATIOS HAVE BEEN 11:1 OR
12:1 AND WILL MAINTAIN THIS FOR SNOW AMOUNT FCST TODAY...THEN
INCREASE A BIT CLOSER TO 14:1 ON SATURDAY. THIS YIELDS FROM 12Z
FRI TO 00Z SUN ADDITIONAL SNOWFALL OF 9 TO 11 INCHES IN MOST OF
THE AREA WITH CLOSER TO 7 IN THE FAR EAST (WHERE DRIER AIR WILL
MOVE INTO THIS AFTN) AND THE FAR NORTH ALONG THE CANADIAN BORDER.
THIS WILL STILL MAKE STORM TOTALS FROM WED NIGHT OF 12 INCHES
NORTH TO 16 TO 20 INCHES SOUTH. THIS HAS BEEN VERY PERSISTANT AND
SEE NO REASON TO DEVIATE.
AT THE SFC THIS MORNING...LOW WAS JUST EAST OF KIRKSVILLE MISSOURI
WITH PRESSURE FALLS TOWARD OTTUMWA IOWA. ALSO NOTED AS A SECOND
PRESSURE FALL NEAR WHEATON MN ALONG NRN END OF INVERTED TROUGH.
LOW WILL MOVE INTO SE IA AND THEN MOVE MORE NORTHWEST TO A
LOCATION NEAR FORT DODGE IOWA TONIGHT INTO SATURDAY AND THEN FILL
AND SHIFT EAST. THE INVERTED TROUGH WILL GRADUALLY WASH OUT WITH
WINDS ALL AREAS TURNING DUE NORTH. WITH STORM MOVING CLOSER BY
GRADIENT WINDS ALONE WILL CAUSE 20 TO 25 KT SUSTAINED WINDS IN THE
VALLEY AND ERN ND. MIXED LAYER IS SHALLOW BUT DOES SHOW 35 KTS
WILL EASILY MIX DOWN LATE THIS MORNING INTO AFTN WHEN THE WINDS
SHOULD MAXIMIZE. FARTHER EAST...ROX-TVF-PKD A BIT MORE NORTHEAST
WIND TODAY AND A BIT LESS GRADIENT AND MIXED LAYER WINDS SO WILL
USE AREAS OF BLOWING SNOW THRU TONIGHT.
SATURDAY WILL SEE WINDS GRADUALLY WIND DOWN AND SNOW TAPER
OFF...ALTHOUGH MODELS DO INDICATE SOME BANDING OF SNOW STILL
TAKING SHAPE. WARNINGS WILL END AT 18Z SAT AND THEY MAY NEED TO BE
EXTENDED TIL 00Z OR BE REPLACED BY A ADVISORY. LATER SHIFTS CAN
HANDLE THAT.
AS FOR TEMPERATURES....VERY INTERESTING. NEED TO RAISE TEMPS IN
MOST AREAS AS NAM12 FROM THURSDAY HIT THE WARM AIR MOVING BACK IN
FROM THE NORTHEAST VERY WELL. NAM12 IN FACT BRINGS THE 30-32
DEGREE AIRMASS NOW IN BRAINERD WEST TO FERGUS FALLS BY NOON AND
KEEPS IT THERE THRU TONIGHT. I CAN BUY THAT AND DID RAISE TEMPS
BUT STAYED JUST BLO 32F. WARMER AIR WILL REACH THE FAR WRN FCST
AREA AS WELL WITH TEMPS RISING INTO THE 15-25 RANGE LATER TODAY
AND TONIGHT. WILL KEEP THESE MILD TEMPS IN THRU SATURDAY AS LOW
FILLS AND WARM AIR CONTINUES TO GET WRAPPED AROUND THE SYSTEM.
LONG TERM...
NO CHANGES WERE MADE. BUT IN THE VERY LONG RANGE...ECMWF AND GFS
ALL CONTINUE TO SHOW IDEA OF A COLD AIR OUTBREAK AROUND NEW YEARS
DAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...BLIZZARD WARNING UNTIL NOON CST SATURDAY FOR NDZ006>008-014>016-
024-026>030-038-039-049-052>054.
MN...BLIZZARD WARNING UNTIL NOON CST SATURDAY FOR MNZ001>004-007-029-
030-040.
WINTER STORM WARNING UNTIL NOON CST SATURDAY FOR MNZ005-006-008-
009-013>017-022>024-027-028-031-032.
&&
$$
DK
