Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 171745
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1145 AM CST WED DEC 17 2014

.UPDATE...
ISSUED AT 1145 AM CST WED DEC 17 2014

GRAVITY WAVE AND SURFACE CONVERGENCE ZONE IS EXPECTED TO PERSIST
THROUGH THIS AFTERNOON. RADAR RETURNS HAD DIMINISHED SLIGHTLY
DURING THE MORNING...BUT EXPECT SNOW RATES TO INCREASE GRADUALLY
THROUGH THE AFTERNOON WITH CONVERGENCE AND GRAVITY WAVE STILL IN
PLACE. WILL EXTEND WINTER WEATHER ADVISORY FOR BAYFIELD COUNTY
THROUGH 6 PM. ADDITIONAL SNOWFALL THIS AFTERNOON FROM NORTHEAST
DOUGLAS ALONG THE HIGH TERRAIN IN BAYFIELD COUNTY OF UP TO 1.5
INCHES IS EXPECTED...WITH LESS THAN ONE TENTH FARTHER INLAND AND
IN THE LOWER TERRAIN. SNOWS OVER NORTHERN IRON AND NORTHEAST
ASHLAND COUNTY WILL CONTINUE THIS AFTERNOON...AND THE FOCUS SHOULD
SHIFT SLIGHTLY FARTHER WEST ALONG THE HIGH TERRAIN FROM ODANAH
EAST TO HURLEY. ADDITIONAL SNOWFALL OF UP TO 1 IS POSSIBLE IN
THOSE AREAS...WITH LESS THAN ONE TENTH FARTHER INLAND.

UPDATE ISSUED AT 1128 AM CST WED DEC 17 2014

UPDATED FOR THE NEW 18Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CST WED DEC 17 2014

PRIMARY CONCERN FOR THE SHORT TERM PERIOD WAS LAKE EFFECT SNOWFALL
EVENT THIS MORNING AND INTO TODAY ACROSS THE SOUTH SHORE OF LAKE
SUPERIOR. OTHERWISE SEASONABLE CONDITIONS TODAY AND TOMORROW AS AN
AREA OF HIGH PRESSURE SETTLES IN ACROSS THE NORTHLAND.

EARLY THIS MORNING...OVERNIGHT RADAR RETURNS AND SURFACE
OBSERVATIONS INDICATED WIDESPREAD LIGHT SNOWFALL CONTINUED ACROSS
NORTHERN MINNESOTA. AS NEAR-SURFACE WINDS BACKED TO THE WEST LAKE
EFFECT SNOWFALL ACROSS THE SOUTH SHORE HAD TAPERED OFF...BUT AM
EXPECTING SNOW SHOWERS TO REDEVELOP TOWARDS SUNRISE THIS MORNING.
TEMPERATURES WERE HOLDING STEADY IN THE LOW TEENS ACROSS NORTHERN
MINNESOTA AND IN THE UPPER TEENS TO NEAR 20 IN NORTHWEST WISCONSIN.
WINDS WERE LIGHT OUT OF THE NORTHWEST AT 5 TO 10 KTS.

TODAY...THE WIDESPREAD LIGHT SNOW EARLY THIS MORNING WILL GRADUALLY
TAPER OFF AS WIDESPREAD SUBSIDENCE SETS IN DUE TO HIGH PRESSURE
MOVING INTO THE REGION. SKIES WILL BEGIN TO CLEAR PARTIALLY ALONG
THE INTERNATIONAL BORDER...BUT MOST LOCATIONS WILL REMAIN OVERCAST
DURING DAYLIGHT HOURS. A FEW FLURRIES WILL BE POSSIBLE IN THE LATE
AFTERNOON...BUT ACCUMULATING SNOWFALL WILL END BY MID-MORNING IN
MOST LOCATIONS. THE EXCEPTION WILL BE ALONG THE SOUTH SHORE OF LAKE
SUPERIOR WHERE LAKE EFFECT SNOW SHOWERS WILL REDEVELOP THIS
AFTERNOON AS THE LOW LEVEL WINDS BETTER ALIGN OUT OF THE NORTH. HAVE
DECREASED SNOWFALL AMOUNTS FROM PREVIOUS FORECASTS BASED ON THE
GUIDANCE AND EARLY MORNING OBSERVATIONS WHICH INDICATED LAKE EFFECT
SNOW SHOWERS HAVE TEMPORARILY DISSIPATED DUE TO BACKING OF
NEAR-SURFACE WINDS. RAP SOUNDINGS FOR THE SOUTH SHORE INDICATE THE
BEST LIFT TO BE BELOW THE DENDRITIC GROWTH ZONE...SO WHILE THERE
WILL BE FORCING AND MOISTURE...THE ALIGNMENT OF THE BEST LIFT MAY
RESULT IN LIMITED CRYSTAL GROWTH/AGGREGATION EXCEPT FOR ALONG THE
HIGHER TERRAIN WHERE MORE INTENSE SNOWFALL RATES COULD OCCUR.

DESPITE THESE RESERVATIONS FOR THE LAKE EFFECT SNOWFALL HAVE DECIDED
TO LEAVE THE CURRENT ADVISORY AND WARNING IN PLACE UNTIL WE BEGIN TO
RECEIVE SNOWFALL REPORTS THIS MORNING TO CONFIRM RADAR AND AUTOMATED
SURFACE OBSERVATIONS...BUT AM LEANING TOWARDS AN EARLY CANCELLATION
FOR THE WARNING AS ADDITIONAL AMOUNTS TODAY WILL PROBABLY ONLY BE IN
THE 1 TO 3 INCH RANGE.

HIGHS TODAY IN THE UPPER TEENS TO NEAR 20. WINDS WILL GRADUALLY VEER
TO THE NORTH/NORTHEAST AND WEAKEN TO 5 KTS OR LESS BY THE LATE
AFTERNOON.

TONIGHT...SOME CLEARING ALONG THE ARROWHEAD REGION OVERNIGHT WITH
NEAR CALM WINDS. A FEW LINGERING LIGHT SNOW SHOWERS/FLURRIES ALONG
THE SOUTH SHORE OF LAKE SUPERIOR. LOWS NEAR ZERO ALONG THE
INTERNATIONAL BORDER AND OTHER LOCATIONS WHERE SKIES MIGHT
CLEAR...ELSEWHERE IN THE LOW TEENS.

THURSDAY...INCREASING CLOUDS AS A MID-LEVEL DISTURBANCE MOVES EAST
ACROSS THE NORTHERN PLAINS AND INTO THE UPPER MIDWEST. THE 00Z HIRES
ARW DEPICTS AN AREA OF CONVERGENCE AND SNOW SHOWER DEVELOPING OVER
LAKE SUPERIOR BETWEEN TWO HARBORS AND HERBSTER...GRADUALLY DRIFTING
WEST TO BRING A FEW FLAKES TO THE NORTH SHORE BETWEEN THE TWIN PORTS
AND TWO HARBORS. DECIDED TO THROW IN A MENTION OF FLURRIES IN THIS
REGION AS WINDS APPEAR TO BE FAVORABLE FOR SUCH A DEVELOPMENT. VERY
LOW CONFIDENCE IN PREDICATION OF A MESOSCALE FEATURE LIKE THIS SO
FAR IN ADVANCE...BUT INTERESTING TO SEE THE HIGHER RESOLUTION ARW
MODEL PICK UP ON IT. HIGHS IN THE LOW TO MID 20S.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 317 AM CST WED DEC 17 2014

FAIRLY QUIET WEATHER PATTERN FOR THE LATTER HALF OF THE WEEK WITH AN
EXITING RIDGE OF HIGH PRESSURE TO THE EAST AND A MILD AND DRY UPPER
TROUGH DROPPING IN FROM THE NW TO PRODUCE LOW CHANCES FOR VERY LIGHT
SNOW SHOWERS LATE FRIDAY INTO SATURDAY. THE SYNOPTIC FLOW WILL
REMAIN CYCLONIC...BUT RELATIVELY DRY THROUGH THE REST OF THE WEEKEND
PRIOR TO A RE-ENFORCING WAVE EJECTING OUT OF THE NRN ROCKIES WITH AN
ASSOCIATED SFC LOW FORMING OVER THE CENTRAL PLAINS SUN NIGHT AND
TRACKING TO THE EAST INTO THE SRN GREAT LAKES BY MON NIGHT/ TUE
MORNING. THIS SYSTEM WILL PRODUCE WIDESPREAD SNOW SHOWERS ACROSS THE
NORTHLAND LATE SUNDAY INTO EARLY NEXT WEEK...AND ALSO USHER IN A
MUCH COOLER AIR MASS GOING INTO THE MIDDLE OF THE WEEK. SNOW AMOUNTS
APPEAR TO BE RELATIVELY LIGHT AT THIS TIME.

TEMPERATURES EARLY IN THE EXTENDED PERIOD WILL BE ON THE COOL SIDE
WITH HIGHS IN THE 20S AND LOWS IN THE TEENS AND SINGLE DIGITS ABOVE
ZERO ON FRIDAY. A SLIGHT WARM UP WILL BE FELT SAT THROUGH MONDAY
WITH HIGHS IN THE 30S AND LOWS IN THE 20S. THE NEXT DROP IN
TEMPERATURES WILL BEGIN TUESDAY WITH HIGHS BACK DOWN INTO THE 20S
AND OVERNIGHT LOWS IN THE TEENS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1128 AM CST WED DEC 17 2014

THERE HAS BEEN SOME CLEARING OVER NE MINNESOTA FROM THE NORTH THIS
MORNING AS HIGH PRESSURE IN MANITOBA AND NW ONTARIO GRADUALLY
APPROACHES THE MINNESOTA. WHILE MOSTLY CLEAR SKIES HAVE RETURNED
TO KINL/KHIB/KDLH...BKN/OVC MVFR CIGS AND IFR/MVFR VSBYS FROM -SN
FARTHER SOUTH...INCLUDING OVER KBRD AND NW WISCONSIN. THE LATEST
FORECASTS REFLECT A GREATER CONFIDENCE IN CLEARING THIS AFTERNOON
AND THIS EVENING. THE MVFR CONDITIONS WILL LIKELY LINGER AT KBRD
FOR AT LEAST EARLY THIS AFTERNOON...AND KHYR WILL NOT LIKELY
RETURN TO VFR UNTIL SOMETIME LATE THURSDAY MORNING DUE TO GREATER
MOISTURE FLOW FROM LAKE SUPERIOR. CLEAR AND CALM WEATHER IS
EXPECTED FOR MUCH OF NE MINNESOTA TONIGHT AS THE HIGH PRESSURE
MOVES THROUGH THE REGION. FOG COULD DEVELOP LATE TONIGHT AND EARLY
THURSDAY MORNING. HINTED AT THIS BY GIVING A PERIOD OF MVFR VSBYS
AT KINL/KHIB/KDLH/KBRD. MUCH OF THE REGION WOULD LIKELY RETURN TO
CLEAR SKIES AND VFR CONDITIONS BY LATE THURSDAY MORNING.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  21  14  24  16 /  30  10  10   0
INL  17   0  20  11 /  10   0   0   0
BRD  17  12  22  14 /  10   0   0   0
HYR  21  13  25  12 /  50  10  10   0
ASX  22  15  25  12 /  60  20  10   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR WIZ003-004.

     WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ002.

LS...NONE.
&&

$$

UPDATE...HUYCK
SHORT TERM...JJM
LONG TERM...BJT
AVIATION...GROCHOCINSKI







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