Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 021146
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
546 AM CST TUE FEB 2 2016

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 418 AM CST TUE FEB 2 2016

THE FOCUS REMAINS ON THE APPROACHING WINTER STORM SYSTEM AND ITS
EFFECTS TO THE NORTHLAND. IN GENERAL...THE 00Z MODELS HAVE
MAINTAINED THE NORTHWARD TREND IN THE TRACK OF THE LOW PRESSURE
SYSTEM THAT BEGAN WITH THE PREVIOUS 12Z MODEL RUNS. THE MORE
NORTHERN TRACK WILL CAUSE THE STORM TO HAVE A GREATER IMPACT ON
THE NORTHLAND. THE COMBINATION OF THE CONFIDENCE IN THE MORE
NORTHERN TRACK...AS WELL AS HIGHER PCPN IN THE FORECAST BECAUSE OF
THE INCORPORATION OF HIGHER RESOLUTION MODEL GUIDANCE AND A
GENERAL INCREASE IN MODELED PCPN...HAS RESULTED IN INCREASING THE
SNOWFALL FORECAST. THE INCREASE IN THE SNOWFALL FORECAST WARRANTED
ISSUING WINTER STORM WARNINGS FOR BAYFIELD AND WASHBURN
COUNTIES...PREVIOUSLY ADVISORIES...AND AN ADVISORY FOR PINE
COUNTY. ALSO...REFINED THE TIMING OF ALL HEADLINES TO BETTER
REFLECT WHEN THE SNOW WILL BEGIN AND END.

A VERTICALLY STACKED AREA OF LOW PRESSURE OVER KANSAS...AS OF
EARLY THIS MORNING...WILL LIFT THROUGH THE SOUTHERN AND CENTRAL
PLAINS TOWARDS THE GREAT LAKES TODAY AND TONIGHT. IT WILL CROSS
CENTRAL OR NORTHERN LAKE MICHIGAN EARLY WEDNESDAY AND THEN LIFT
INTO CANADA WEDNESDAY AFTERNOON AND EVENING. THIS WINTER STORM
SYSTEM WILL AFFECT MUCH OF THE UPPER MIDWEST AND WESTERN GREAT
LAKES REGION TODAY AND INTO WEDNESDAY...BRINGING MODERATE TO HEAVY
SNOWFALL FOR MUCH OF THE REGION...INCLUDING AS FAR AS PARTS OF THE
NORTHLAND.

THE NORTHLAND CAN EXPECT INCREASING CLOUD COVER FROM THE SOUTH
TODAY AS THE STORM SYSTEM APPROACHES THE UPPER MIDWEST. THE
INITIAL BAND OF SNOW WILL SPREAD NORTHWARD INTO THE NORTHLAND THIS
AFTERNOON ALONG A WIDE BAND OF MID/UPPER LEVEL FRONTOGENESIS. THE
SNOW INTENSITY WILL QUICKLY PICK UP LATER THIS AFTERNOON AND
CONTINUE AT ITS GREATEST INTENSITY THROUGH AT LEAST THIS EVENING.
NORTHWEST WISCONSIN WILL BE MOST AFFECTED...FOLLOWED BY NEARBY
AREAS OF NE MINNESOTA AND THE NORTH SHORE OF THE MINNESOTA
ARROWHEAD. THE SNOW WILL HAVE GREAT DIFFICULTY MAKING INTO THE
WESTERN AND NORTHERN FORECAST AREA BECAUSE OF THE TRACK OF THE
UPPER LEVEL LOW/TROUGH...AND FROM THE COLD AND DRY LOW LEVEL
NORTHERLY FLOW COMING FROM AN AREA OF SURFACE HIGH PRESSURE IN
ONTARIO AND MANITOBA.

WHILE THE BAND OF FRONTOGENESIS EXITS THE NORTHLAND LATER THIS
EVENING...THERE WILL CONTINUE TO BE FORCING FOR SYNOPTIC SNOW
THROUGH EARLY WEDNESDAY...ESPECIALLY BECAUSE OF THE UPPER LEVEL
LOW/TROUGH WILL LIFT RIGHT OVER THE NORTHLAND OVERNIGHT AND
WEDNESDAY MORNING.

THE SYSTEM WILL GRADUALLY SHIFT EAST AND DISTANCE ITSELF FROM THE
NORTHLAND WEDNESDAY...WHICH WILL CAUSE THE FORCING FOR THE
LINGERING LIGHT SYNOPTIC SNOW TO COME TO AN END. HOWEVER...COLD
NORTHWEST FLOW WILL DEVELOP OVER WESTERN LAKE SUPERIOR...RESULTING
IN LINGERING LAKE EFFECT SNOW SHOWERS DOWNWIND AREAS OF NW
WISCONSIN THROUGH WEDNESDAY AFTERNOON.

GUSTY WINDS...AS HIGH AS 25 MPH...WILL ACCOMPANY THE FALLING SNOW
AND CAUSE PERIODS OF LOW VISIBILITY. WIDESPREAD SNOWFALL OF 6 TO
10 INCHES IS FORECAST FOR PARTS OF NW WISCONSIN...MAINLY NEAR AND
EAST OF HIGHWAY 63. PARTS OF NORTHERN IRON AND ASHLAND
COUNTIES...ESPECIALLY ALONG AND NEAR HIGHWAY 2...COULD SEE AS MUCH
AS 11 INCHES. LESSER AMOUNTS OF 3 TO 6 INCHES ARE FORECAST FOR THE
REST OF NW WISCONSIN...AND PINE COUNTY IN NE MINNESOTA. THE
AITKIN...TWIN PORTS...AND NORTH SHORE SHOULD ONLY GET 1 TO 2
INCHES AT MOST.

LOOKED INTO THE THREAT OF POTENTIAL DENDRITIC GROWTH ENHANCEMENT
AND HIGH SNOW TO LIQUID RATIOS. THE 00Z GFS AND 00Z NAM12 WERE
HINTING AT A POSSIBLE SHORT WINDOW OF DECENT VERTICAL LIFT AROUND
THE -15 DEGREE CELSIUS ZONE ALOFT. HOWEVER...WAS NOT CONFIDENT TO
LEAN ON THE HIGHER MODELS SNOW TO LIQUID RATIOS IN THE GFS AND
NAM12. THEREFORE...IF CONFIDENCE INCREASES IN THIS
POTENTIAL...THE SNOWFALL FORECASTS MIGHT NEED TO BE INCREASED WITH
SUBSEQUENT UPDATES. THE RAP13 WILL SOON GO OUT THROUGH THIS
EVENING...AND GIVE US ANOTHER MODEL TO COMPARE TO THE GFS AND
NAM12 TO EXAMINE THIS POTENTIAL FACTOR.

HIGH TEMPERATURES WILL RANGE FROM THE UPPER 20S AND LOW 30S
ACROSS THE SOUTH TO THE LOW 20S ACROSS THE NORTH. TONIGHT...LEANED
ON THE CANADIAN REGIONAL BECAUSE OF ITS WARMER TEMPERATURES
DOWNWIND OF THE FLOW OVER LAKE SUPERIOR. LOWS SHOULD RANGE FROM
THE LOW 20S IN PRICE COUNTY...TO THE MIDDLE SINGLE DIGITS NEAR
KOOCHICHING COUNTY. WEDNESDAY SHOULD HAVE HIGHS IN THE TEENS
ACROSS NE MINNESOTA AND THE LOW 20S ACROSS NW WISCONSIN.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 418 AM CST TUE FEB 2 2016

WEAK MID LEVEL AND SFC RIDGING MOVE OVER THE FORECAST AREA
WEDNESDAY EVENING. A NW FLOW WILL BE ONGOING OVER THE SOUTH SHORE
OF LAKE SUPERIOR...BUT TURNING TO A WNW DIRECTION BY 06Z. THIS
WILL AFFECT ANY LAKE EFFECT SNOW SHOWERS AS THE FETCH CHANGES AND
WAA BEGINS IN THE 1000-900MB LAYER. WILL KEEP THE HIGHEST POPS IN
IRON COUNTY...BUT LOWER THEM FURTHER WEST. THE WIND TURNS
SOUTHWEST OVERNIGHT. THIS IS WHEN AN UPPER TROF MOVES INTO MN.
SOME LIGHT SNOW WILL SPREAD ACROSS NE MN BY 12Z...BUT AMOUNTS WILL
BE LIGHT WITH MINIMAL MOISTURE TO WORK WITH. KEPT WITH THE
PREVIOUSLY FORECAST POPS ON THURSDAY AS THE TROF MOVES INTO WI AND
SOME CHANNELED VORTICITY FOLLOWS BEHIND. SFC RIDGING PUSHES ACROSS
THE REGION THURSDAY NIGHT. MODEL DIFFERENCES SHOW UP ON FRIDAY
WITH THE STRENGTH OF A POSITIVELY TILTED UPPER LONG WAVE TROF
MOVING INTO MN BY 00Z SATURDAY. THE ECMWF HAS A SFC LOW REFLECTION
INTO WESTERN MN WHILE THE GFS IS MORE NEBULOUS. THE ECMWF HAS A
GENEROUS QPF FIELD WHILE THE GFS IS LIGHTER. USED A BLENDED
APPROACH FOR POPS/QPF/SNOW. THE MODEL DIFFERENCES CONTINUE FRIDAY
NIGHT ESPECIALLY IN REGARDS TO QPF AS THE GFS IS ALREADY BRINGING
IN A SECOND ROUND OF LIGHT SNOW...WHILE THE ECMWF PUSHES EWD WITH
THE SFC LOW AND ITS QPF ALLOWING DRY SFC RIDGING TO COVER THE AREA
LATE. MAINTAINED THE BLENDED POPS/QPF/SNOW. THE GFS BRINGS A WARM
FRONT THROUGH THE AREA SATURDAY WHILE THE ECMWF HAS HIGH PRESSURE.
LEANED A BIT TOWARD THE GFS AND HAVE SOME LOW POPS. SATURDAY NIGHT
AND SUNDAY FINDS A LARGE AREA OF LOW PRESSURE DEEPENING AS IT
MOVES NEARBY. HOWEVER...THE TRACKS ARE SIGNIFICANTLY DIFFERENT
WITH THE ECMWF TAKING THE LOW DIRECTLY OVERHEAD...WHILE THE GFS
HAS THE LOW CENTER IN NW ONTARIO BY 00Z MONDAY. REGARDLESS...HAVE
A GRADUAL INCREASE IN POPS TO ACCOUNT FOR THIS TREND.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 546 AM CST TUE FEB 2 2016

MAINLY VFR CIGS AT THE START OF THE FORECAST WITH A POCKET OF MVFR
CIGS IN NW WI. EXPECT THESE CONDITIONS TO PERSIST UNTIL ABOUT 18Z
WHEN IFR/LIFR CIGS/VSBYS BEGIN TO PUSH NWD AHEAD OF THE WINTER
STORM. THE LIGHT SNOW SHOULD REACH BRD/HYR AROUND 20Z WITH VSBYS
QUICKLY DROPPING INTO THE IFR/LIFR RANGE IN LIGHT TO MODERATE
SNOW. MODERATE TO HEAVY SNOW IS EXPECTED AT HYR BY 22Z THROUGH
03Z WITH VLIFR VSBYS...THEN IMPROVING TO MVFR VSBYS IN LIGHT
SNOW. ELSEWHERE...THE SNOW WILL SPREAD ACROSS ALL BUT INL BY 22Z
WITH MVFR/IFR CONDITIONS. EXPECT INL TO BE VFR THROUGH THE
FORECAST. GUSTY SFC WINDS WITH PATCHY BLSN IS POSSIBLE AFTER 22Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  26  12  17   2 /  30  70  30  10
INL  19   4  14  -1 /   0   0   0  20
BRD  27  12  19   6 /  20  50  10  20
HYR  31  18  22   0 /  90 100  50  10
ASX  29  20  22   5 /  70 100  80  20

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST WEDNESDAY
     FOR WIZ006.

     WINTER STORM WARNING FROM NOON TODAY TO 9 AM CST WEDNESDAY FOR
     WIZ007>009.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 3 PM CST
     WEDNESDAY FOR WIZ002>004.

     WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
     WEDNESDAY FOR WIZ001.

MN...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST WEDNESDAY
     FOR MNZ038.

LS...NONE.
&&

$$

SHORT TERM...GROCHOCINSKI
LONG TERM...GSF
AVIATION...GSF


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