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000
FXUS63 KDLH 021013
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
413 AM CST MON DEC 2 2013

.SYNOPSIS...
ISSUED AT 412 AM CST MON DEC 2 2013

INTERESTING...DYNAMIC AND AMAZING SYSTEM SETTING UP OVER THE
NORTHERN PLAINS EARLY THIS MORNING.  A SURFACE LOW DEVELOPING OVER
EASTERN MONTANA...ALONG WITH A NICE UPPER LEVEL SHORTWAVE.  THESE
FEATURES ARE OCCURRING OUT AHEAD OF A STRONG UPPER LOW THAT HAS BEEN
DROPPING SOUTH ALONG THE WESTERN BRITISH COUMBIA COASTLINE.  MORE
LOCALLY...THE WARM FRONT WITH THIS SYSTEM EXTENDS FROM THE SURFACE
LOW OVER MONTANA SOUTHEAST ACROSS THE PLAINS TO EASTERN KANSAS.
850MB FLOW STREAMING UP OVER THIS HAS PRODUCED A BROAD AREA OF WARM
AIR ADVECTION OVER THE UPPER MIDWEST THIS MORNING. IT HAS ALSO
PRODUCED AN AREA OF LIGHT SNOW THAT IS MOVING FROM THE EASTERN
DAKOTAS INTO MINNESOTA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CST MON DEC 2 2013

MAIN FOCUS THE NEXT 24 HOURS IS GOING TO BE ON SNOW TIMING AND
AMOUNTS.  AT LEAST IN THE NEXT 12-24 HOURS THE MODELS ARE IN
REASONABLE CONSENSUS ON THIS...BUT FARTHER OUT THE NAM IS A STRONG
OUTLIER AND HAVE DECIDED TO LEAVE IT OUT OF NEAR TIME RANGE MODEL
BLEND AS WELL.  EARLY THIS MORNING WE HAVE A LEADING BAND OF WARM
AIR ADVECTION WHICH IS EXPECTED TO BE OVERTAKEN AND OVERCOME BY THE
STRONGER WAVE MOVING INTO THE AREA FROM THE WEST LATER TODAY AND
TONIGHT.  THIS MORNINGS SNOW IS EXPECTED TO BE MORE SPOTTY IN NATURE
AND MAY ONLY BRING AN INCH OR LESS OF SNOWFALL ACCUMULATIONS.  THIS
AFTERNOON BETTER LIFT AND A STRONGER FRONTOGENESIS BAND TO SET UP
AND SLOWLY MIGRATE ACROSS THE AREA DURING THE AFTERNOON AND EVENING
HOURS...ALONG WITH A NICE SHORTWAVE ALOFT.  SNOWFALL AMOUNTS WITH
THIS TO BE HIGHER...WITH MORE MOISTURE AVAILABLE FOR THE SYSTEM TO
WORK WITH.  DO HAVE SOME CONCERNS WITH THE VERY WARM AIR COMING INTO
THE SYSTEM FROM THE SOUTH...IN THAT IT COULD PRODUCE SOME PTYPE
ISSUES FOR THE SOUTHERN CWA EARLY TUESDAY MORNING.  IT DEPENDS UPON
THE MODEL WE LOOK AT. FOR NOW HAVE LEFT ALL SNOW...AND WE ARE GOING
TO HAVE TO KEEP AN EYE ON THIS AS THE SYSTEM CONTINUES TO EVOLVE.
FOR NOW HAVE AFTERNOON AND TONIGHT SNOWFALL AMOUNTS RANGING FROM 2-3
INCHES ACROSS THE FAR SOUTH AND NORTHWEST WISCONSIN COUNTIES...TO 4
TO 5 INCHES ACROSS THE NORTHERN MINNESOTA COUNTIES.  THROUGHOUT THIS
PERIOD WE WILL HAVE SOUTHEAST FLOW ACROSS THE AREA...AND BETWEEN
LAKE EFFECTS...CONVERGENCE AND OROGRAPHIC EFFECTS AM EXPECTING
LOCALLY HIGHER AMOUNTS ALONG THE NORTH SHORE OF THE LAKE...PERHAPS
UP INTO THE 6 INCH RANGE.  WE CURRENTLY HAVE A SNOW ADVISORY GOING
FOR MOST OF THE FORECAST AREA THROUGH THIS PERIOD...THOUGH HAVE
TAKEN THE MAINLY MINNESOTA PORTION OF THE ADVISORY AND MOVED IT UP
TO START AT 15Z THIS MORNING.  OTHERWISE...HAVE STAYED FAIRLY CLOSE
TO TEMPERATURE GUIDANCE AS THERE IS VERY LOW VARIANCE BETWEEN MODELS.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM CST MON DEC 2 2013

CONSIDERABLE ANGST EARLY IN THE FORECAST PERIOD BASED ON THE
INCONSISTENCY AMONGST MDL SUITE. MAJOR DISAGREEMENTS ARE EVIDENT
BETWEEN GLOBAL MDLS...UKM/ECMWF/GEM...AND CONUS SUITE...GFS/NAM
WITH REGARD TO TREATMENT OF INITIAL MID LVL SHORTWAVE/CLOSED LOW
OVER MT. BASED ON DISCUSSION FROM PMDHMD AND SOMEWHAT MORE
CONSISTENCY FROM GLBL MDLS..WILL LEAN WITH THE EC/UKM SOLUTION
EARLY IN THE PERIOD. THIS CREATES A SYNOPTIC SCALE SCENARIO THAT
WILL BE VERY SLOW IN EVOLVING. THE PROBABILITY OF A WIDESPREAD
SNOWFALL INCREASING IN INTENSITY APPEARS MORE LIKELY TUES/WED AS
AN INVERTED TROUGH OVER THE PLAINS GIVES WAY TO CYCLOGENESIS. BEST
GUESSTIMATE IS THAT THE SFC LOW WILL TRACK FROM MO/IA VICINITY
INTO WISC BY LATE WED. SREF PLUMES SUGGEST A SIGNIFICANT...GREATER
THAN 6"... SNOWFALL IS POSSIBLE ACROSS A LARGE PART OF THE MN CWA
AND ADJACENT WISC ZONES. PLEASE REFER TO HOW AND WINTER WEATHER
MESSAGES FOR ADDITIONAL INFORMATION. MUCH COLDER AIR WILL BARREL
INTO THE REGION ON THE HEELS OF THIS SYSTEM AND CONTINUE THE
POSSIBILITY OF LIGHT SNOW ACROSS THE NRN TIER OF ZONES AND
POSSIBLY OVER THE SOUTH SHORE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1134 PM CST SUN DEC 1 2013

DIFFICULT FORECAST WITH PRIMARILY MVFR CIGS AT THE BEGINNING OF
THE FORECAST. HOWEVER...AN AREA OF IFR CIGS WITH MVFR VSBYS AND BR
FROM NEAR DLH TO BRD AND A PATCH OF VFR CIGS NEAR HYR. EXPECT
THESE CIGS TO PERSIST UNTIL NEAR 12Z WHEN THE LIGHT SNOW IS DUE TO
COMMENCE. CONFIDENCE IS LOW AS THERE IS A MIX OF IFR AND VFR
UPSTREAM IN THE DAKOTAS THAT SHOULD AFFECT THE TERMINALS. ONCE THE
SNOW IS FULLY UNDERWAY...IFR CIGS AND VSBYS OCCASIONALLY LIFR IN
THE BANDS OF MORE MODERATE TO HEAVIER SNOW.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  30  28  31  23 /  80  80  80  70
INL  27  19  25  11 /  60  70  80  70
BRD  31  28  32  20 /  90  80  80  70
HYR  33  27  34  24 /  80  80  70  70
ASX  33  27  34  27 /  70  70  70  70

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST
     WEDNESDAY FOR MNZ010>012-018>021-025-026-033>038.

WI...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST
     WEDNESDAY FOR WIZ001-006.

     WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
     THURSDAY FOR WIZ002>004-007>009.

LS...NONE.
&&

$$

SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...CANNON
AVIATION...GSF