000
FXUS63 KFGF 012140
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
340 PM CST SUN DEC 1 2013

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 340 PM CST SUN DEC 1 2013

CHALLENGES ABOUND WITH UPCOMING WINTER STORM. MAIN CONCERNS ARE
SNOW AMOUNTS AND ASSOCIATED HEADLINES. GFS/NAM/ECMWF/GEM ARE NOW
IN BETTER AGREEMENT WITH THE TIMING OF THE LEAD SHORT-WAVE
EJECTING OUT OF THE PARENT TROUGH ON TUESDAY...BUT THE NCEP SUITE
CONTINUES TO BE STRONGER THAN THEIR INTERNATIONAL COUNTERPARTS WITH
THE NAM BEING THE MOST INTENSE AND A NORTHERN OUTLIER. WILL USE A
BLENDED SOLUTION OF THE GFS/ECMWF/GEM...BUT THE FINAL TRACK IS
STILL FAR FROM CERTAIN.

FOR TONIGHT...DISORGANIZED BAND OF LIGHT SNOW CURRENTLY STRETCHING
FROM ROLLA TO JAMESTOWN WILL CONTINUE TO DRIFT EASTWARD.
ACCUMULATIONS WILL BE LIGHT...GENERALLY LESS THAN AN INCH. WITH
OVERCAST SKIES AND NO CHANGE IN AIR MASS...LOWS WON/T DROP MUCH
FROM CURRENT OBSERVATIONS WITH TEMPERATURES BY 12 UTC MONDAY IN THE
MID TEENS TO MID 20S.

MOISTURE AND MID-LEVEL LIFT INCREASE ON MONDAY AND MONDAY NIGHT
WITH AREA OF WARM AIR ADVECTION OUT AHEAD OF THE PRIMARY
TROUGH. FRONTOGENESIS IS NOT TOO STRONG...BUT CONVERGENCE ALONG AND
NORTH OF THE 850 HPA LOW TRACK WILL RESULT IN A BAND OF LIGHT SNOW
ACROSS MUCH OF THE FORECAST AREA. WITH FORECAST QPF IN THE 0.2 TO
0.4 INCH RANGE AND AND SNOW RATIOS AROUND 12:1...EXPECT SNOW
AMOUNTS IN THE 3 TO 5 INCH RANGE ALONG AND NORTH OF A LINE FROM
VALLEY CITY TO FARGO TO WADENA. FOR THIS AREA...WILL ISSUE A
WINTER WEATHER ADVISORY FROM 12 UTC MONDAY UNTIL 12 UTC TUESDAY.
ACROSS SOUTHEAST ND INTO FAR WEST-CENTRAL MN...ECMWF AND SREF
SUGGEST THE POSSIBILITY OF FREEZING PRECIPITATION DUE TO A LACK OF
SATURATION ALOFT. CONFIDENCE IN THIS SCENARIO IS NOT HIGH...SO
WILL KEEP P-TYPE AS ALL SNOW FOR NOW WITH SNOW AMOUNTS OF 1-2
INCHES. ADVISORY MAY NEED TO BE EXPANDED IF FREEZING PRECIPITATION
MATERIALIZES. WINDS WILL BE LIGHT FROM THE EAST THROUGH THE DAY...
SO DO NOT ANTICIPATE BLOWING SNOW TO BE MUCH OF AN ISSUE.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 340 PM CST SUN DEC 1 2013

ATTENTION THEN TURNS TO THE BIG SHOW ON TUESDAY AS THE SURFACE LOW
EJECTS FROM THE CENTRAL ROCKIES AND ACROSS THE UPPER MIDWEST.
PWATS INCREASE TO NEAR 0.5 INCHES AND WITH STRONG ISENTROPIC LIFT
ALONG WARM CONVEYOR BELT...COMBINED WITH DIFFLUENCE ALOFT...
PERIODS OF MODERATE TO HEAVY SNOW ARE EXPECTED TO DEVELOP AND MOVE
ACROSS THE FORECAST AREA THROUGH THE DAY. WITH QPF AMOUNTS GREATER
THAN 0.6 INCHES...SNOW AMOUNTS IN EXCESS OF 6 INCHES ARE A REAL
POSSIBILITY. WINDS ALSO INCREASE AND SHIFT TO THE NORTH TUESDAY
NIGHT...INCREASING THE POTENTIAL FOR BLOWING AND DRIFTING SNOW.
FOR HEADLINE PURPOSES...WILL TREAT TUESDAY/S SNOW SEPARATELY FROM
THAT WHICH FALLS ON MONDAY SINCE THERE WILL LIKELY BE A 6 TO 12
HOUR GAP WITH LITTLE TO NO SNOW FALLING BETWEEN THE TWO EVENTS.
WILL ISSUE A WINTER STORM WATCH FOR THE ENTIRE FORECAST AREA FROM
12 UTC TUESDAY THROUGH 00 UTC THURSDAY.

WEDNESDAY THROUGH SUNDAY...THE WINTER STORM SHOULD BE WRAPPING UP
WEDNESDAY NIGHT AS THE LEAD UPPER LOW MOVES OFF INTO ONTARIO. SNOW
WILL LINGER MAINLY OVER NORTHERN AND EASTERN COUNTIES...BUT WILL
BE STARTING TO TAPER OFF OVERNIGHT. CONTINUED TO KEEP LOW POPS IN
THE NORTHEAST THROUGH THE END OF THE WEEK AS WEAK REINFORCING
SHORTWAVES MOVES THROUGH. THE MAIN STORY FOR THE EXTENDED PERIOD
WILL BE THE EXTREME COLD. ARCTIC AIR WILL STAY IN PLACE THROUGH
THE WEEKEND WITH A GREATER THAN 1040MB HIGH OVER THE NORTHERN
PLAINS AND VERY LOW 1000-500MB THICKNESS VALUES. CONTINUED TO KEEP
HIGHS AROUND ZERO ON THURSDAY AND FALLING TO BELOW ZERO FOR FRIDAY
AND INTO THE WEEKEND. LOWS SHOULD BE DOWN AROUND THE 15 TO 20
BELOW RANGE AND SOME EVEN LOWER...NEAR RECORD VALUES NOT OUT OF
THE QUESTION. THERE IS STRONG CONSENSUS FOR COLD FOR MUCH OF THE
PERIOD...BUT THERE ARE SOME DIFFERENCES IN THE PATTERN BY SUNDAY.
THE ECMWF DIGS THE NEXT TROUGH MUCH FURTHER SOUTH AND
WEST...BRINGING A STORM SYSTEM CLOSE TO OUR SOUTHERN COUNTIES. THE
GFS IS DRIER AND A TAD WARMER WITH THE A REINFORCING SHORTWAVE NOT
DIGGING DOWN INTO THE NORTHERN PLAINS UNTIL NEXT MONDAY. ALLBLEND
PUTS SOME LOW POPS IN THE SOUTH AND EAST AT THE TAIL END OF THE
EXTENDED...AND THAT SEEMS REASONABLE AT THIS POINT DUE TO THE
UNCERTAINTY. TEMPS WILL CONTINUE TO BE ABOUT 20-30 DEGREES BELOW
SEASONABLE NORMALS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 107 PM CST SUN DEC 1 2013

IFR AND LOWER CIGS WILL CONTINUE THROUGH THE EARLY AFTERNOON. SAT
LOOP SHOWS SOME CLEARING ON THE BACK SIDE OF THE TROUGH AXIS IN
WESTERN ND...BUT MODELS ALL HAVE THE SFC TROUGH STARTING TO WASH
OUT...WITH THE WESTERLY WINDS NEVER REACHING OUR FORECAST AREA.
THINK THAT THE STRATUS WILL CONTINUE THROUGH THE REST OF THE
DAY...POSSIBLY LIFTING TO MVFR LEVELS FOR A BRIEF PERIOD. CONDITIONS
WILL DETERIORATE AGAIN THIS EVENING AS CIGS DROP BACK DOWN BELOW
1000 FT AND A BAND OF LIGHT SNOW MOVES IN. THE SNOW WILL BE BRIEF
AND ONLY AFFECT TAF SITES FOR A FEW HOURS WITH VIS AROUND 2SM OR SO.
HOWEVER...AFTER THE SNOW MOVES OFF TO THE EAST THE LOW CIGS AND SOME
MIST WILL CONTINUE. THERE WILL BE ANOTHER...HEAVIER BAND OF SNOW
BEGINNING TO MOVE INTO THE FORECAST AREA LATE IN THE PERIOD. THE
BAND COULD BE AS FAR EAST AS KFAR AND KGFK BY 18Z...BUT FOR NOW WILL
JUST INCLUDE A MENTION AT KDVL.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
     AFTERNOON FOR NDZ006>008-014>016-024-026>030-038-039-049-
     052>054.

     WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR
     NDZ006>008-014>016-024-026>030-038-039-054.

MN...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
     AFTERNOON FOR MNZ001>009-013>017-022>024-027>032-040.

     WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR
     MNZ001>009-013>017-022>024-027-028-031-032.

&&

$$

SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...JR