Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 150538
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1138 PM CST SUN DEC 14 2014

.UPDATE...
ISSUED AT 1135 PM CST SUN DEC 14 2014

UPDATED FOR NEW AVIATION FORECAST DISCUSSION BELOW.

UPDATE ISSUED AT 532 PM CST SUN DEC 14 2014

UPDATED FOR NEW AVIATION FORECAST DISCUSSION BELOW.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 324 PM CST SUN DEC 14 2014

MAIN FORECAST CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND THE
DENSE FOG THAT HAS PLAGUED THE AREA THE PAST 3 TO 4 DAYS...ALONG
WITH THE NEXT WINTER SYSTEM EXPECTED TO IMPACT THE NORTHLAND
BEGINNING MONDAY MORNING AND CONTINUING INTO TUESDAY WITH A WINTRY
MIX OF RAIN...SLEET...FREEZING RAIN AND SNOW.

HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW...SLEET AND FREEZING
RAIN BEGINNING 10 AM MONDAY MORNING INITIALLY ACROSS THE N-CENTRAL
MN COUNTIES AND EVENTUALLY PUSHING EWD INTO NE MN/NW WI BY THE MID
AFTERNOON. TRAVEL CONDITIONS WILL LIKELY DETERIORATE THROUGH THE DAY
ACROSS MUCH OF THE REGION.

A POTENT UPPER LOW IS CURRENTLY EJECTED EWD OUT OF THE SRN ROCKIES
THIS AFTERNOON AND WILL TRACK TO THE EAST THROUGH KS/MO/IA/IL
TONIGHT AND TOMORROW. THERE IS ALSO A SECONDARY COLD UPPER S/W
DROPPING IN FROM THE NORTH THROUGH ND THAT WILL AID IN THE LARGE
SCALE LIFT FOR SNOW SHOWERS AS THE MAIN SRLY LOW DEPARTS TO THE EAST
MON NIGHT AND TUE. AT THE SFC A DUAL LOBE LOW PRESSURE SYSTEM WILL
LIFT SLOWLY TO THE E/NE FROM THE FRONT RANGE OF THE ROCKIES INTO THE
UPPER MIDWEST THIS AFTERNOON AND TONIGHT. THE NRN BRANCH WILL REMAIN
DISCONNECTED FROM THE SRN LOW THROUGH MON NIGHT...BUT EVENTUALLY
PHASE TOGETHER ON TUE OVER THE GREAT LAKES. THE LOW TO THE SOUTH AND
INCOMING S/W FROM THE NORTH WILL COMBINE WITH A FAVORABLE THERMAL
PROFILE TO PRODUCE WINTRY CONDITIONS LATE MON MORNING THROUGH MON
NIGHT.

THE PERSISTENT RIDGE OF HIGH PRESSURE OVER THE MIDWEST WITH A STRONG
LOW LEVEL INVERSION AND SUFFICIENT MOISTURE IN THE BOUNDARY LAYER
WILL CONTINUE TO PRODUCE FOG AND LOW CLOUDS OVER THE REGION THROUGH
MONDAY MORNING. AS THE SFC LOW APPROACHES TONIGHT...WILL LIKELY SEE
THE DEPTH OF THE MOIST LAYER DEEPEN AND POTENTIALLY CHANGE THE
DRIZZLE OVER TO LIGHT RAIN. AS THE MIXING INCREASING MON MORNING THE
FOG AND LOW CLOUDS SHOULD BEGIN TO SCOUR OUT...ESPECIALLY AS THE
COLD FRONT MOVES THROUGH IN THE AFTERNOON. A DENSE FOG ADVISORY
CONTINUES FOR THE ENTIRE REGION THROUGH NOON MONDAY. THE WARM
BUBBLE OF AIR ALOFT WILL ALLOW THE PRECIP TO REMAIN AS LIQUID MOST
OF DAY TOMORROW ACROSS THE ERN HALF OF THE FORECAST AREA...BUT
THE COLD AIR IN THE LOW LEVELS WILL UNDERCUT THIS WARM LAYER AND
CHANGE THE RAIN OVER TO A SLEET/FREEZING RAIN/RAIN MIX IN THE
MORNING OVER N-CENTRAL MN. AS THE COLD FRONT MARCHES EWD MON
AFTERNOON...THE RAIN WILL CHANGE TO THE WINTRY MIX...AND
EVENTUALLY TO SNOW BEHIND THE FRONT.

THERE IS A CONCERN FOR AN AREA OF ENHANCED QPF LATE MON AFTERNOON
ASSOCIATED WITH A BAND OF 850-925MB F-GEN AND WEAK ELEVATED CAPE
EXTENDING FROM JUST EAST OF LAKE MILLE LACS NE TO THE TWIN
PORTS...ALONG THE NORTH SHORE AND INTO PORTIONS OF FAR NW WI. IF
THIS LAYER REMAINS WARM THEN MOST OF THE PRECIP WILL FALL AS RAIN.
HOWEVER...IF ENOUGH LIQUID FALLS INTO THIS LAYER TO DROP THE
TEMPERATURES BELOW FREEZING THE POTENTIAL FOR A PERIOD OF HEAVY SNOW
WILL BE POSSIBLE...OR IF THE SFC TEMPS COOL QUICKER THAN THE
ELEVATED WARM LAYER THE THREAT FOR SIGNIFICANT ACCUMULATING ICE WILL
INCREASE.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 324 PM CST SUN DEC 14 2014

MAIN CONCERN FOR LONG TERM WILL BE MONDAY NIGHT INTO WEDNESDAY WHEN
A WINTRY MIX WILL BE CHANGING OVER TO ALL SNOW...GENERALLY
ACCUMULATING ONE TO THREE INCHES IN MOST LOCATIONS...WITH LAKE
EFFECT PROCESSES ENHANCING TOTALS ALONG THE SOUTH SHORE OF LAKE
SUPERIOR WHERE HIGHER AMOUNTS ARE EXPECTED. WHILE SNOWFALL WILL END
IN MOST LOCATIONS BY TUESDAY AFTERNOON...LAKE EFFECT SNOWFALL ALONG
THE SOUTH SHORE WILL CONTINUE INTO WEDNESDAY...ENDING SOMETIME
WEDNESDAY EVENING.

ON THE SYNOPTIC SCALE THERE WILL BE SOME INTERESTING PHASING OF TWO
UPPER LOWS EARLY THIS WEEK. AS THE STRONGER SOUTH STREAM UPPER LOW
LIFTS FROM THE CENTRAL MISSISSIPPI VALLEY REGION NORTHEAST TO THE
LOWER GREAT LAKES A MUCH DEEPER UPPER LOW WILL DROP SOUTH ALONG A
POSITIVELY TITLED TROUGH. THIS SECOND AND DEEPER UPPER LOW WILL BE
OVER NORTHERN MINNESOTA INTO THE UPPER GREAT LAKES BY TUESDAY
NIGHT...BUT QUICKLY MOVE EAST AS A MID LEVEL RIDGE MOVES IN ACROSS
THE NORTHERN PLAINS AND CANADIAN PRAIRIE. AT THE SURFACE THE MAIN LOW
PRESSURE WILL BE ASSOCIATED WITH THE SOUTHERN STREAM UPPER
LOW...WITH AN ARCTIC HIGH PRESSURE DEVELOPING IN ITS WAKE ACROSS
MINNESOTA LATE IN THE WEEK. THERE IS A CHANCE FOR A WEAK CLIPPER
SYSTEM THIS WEEKEND...BUT OTHERWISE BEYOND THIS EARLY WEEK SYSTEM
THE REST OF THE WEEK AND INTO THE WEEKEND LOOK TO BE BENIGN WEATHER
WISE. THE GOOD NEWS...WHILE TEMPERATURES MAY BE BACK TO THE MORE
TYPICAL 20S AS HIGHS...SUN IS ON THE WAY!

MONDAY NIGHT...TRANSITIONAL PERIOD FROM RAIN...TO A QUICK WINTRY
MIX...THEN TO ALL SNOW ACROSS THE NORTHLAND. BY 00Z TUES /6 PM CST
MON NIGHT/ A WINTRY MIX WILL BE FALLING ACROSS MOST OF OF NORTHERN
MINNESOTA...WHILE LIGHT TO MODERATE RAIN WILL BE ONGOING ALONG THE
INTERSTATE 35 CORRIDOR AND EAST INTO NORTHWEST WISCONSIN. COLD AIR
WILL BE QUICKLY MOVING IN FROM THE NORTHWEST...AND BY MIDNIGHT ALL
PRECIPITATION WILL TRANSITION OVER TO A LIGHT TO MODERATE SNOW.
LOOKING AT TEMPERATURES ALOFT...THERE COULD BE A SHORT PERIOD OF
FREEZING RAIN BEFORE THE TRANSITION TO ALL SNOW...BUT IN GENERAL
THIS TIMEFRAME WILL BE LIMITED BY THE EVENING AS THE COLD AIR ALOFT
CATCHES UP TO THE COLD AIR AT THE SURFACE. AREAS IN NORTHERN
MINNESOTA SOUTH OF HIGHWAY 2...PARTICULARLY THE BRAINERD LAKES
REGION...COULD EXPERIENCE BLOWING SNOW IN THE EVENING AND INTO THE
OVERNIGHT. MODEL SOUNDINGS INDICATE WINDS COULD GUST TO NEAR 30 KTS
AT TIMES...WHICH COULD CAUSE BLOWING SNOW. LOW TEMPERATURES IN THE
LOW TO UPPER TEENS...EXCEPT IN NORTHERN WISCONSIN WHERE TEMPERATURES
MAY ONLY DROP TO THE LOW 20S.

TUESDAY...SNOWFALL WILL END FROM WEST TO EAST...ENDING FOR THE
MORNING COMMUTE IN NORTHERN MINNESOTA. IN NORTHWEST WISCONSIN SOME
LIGHT SNOW COULD CONTINUE OFF AND ON THROUGH THE MID MORNING
HOURS...EXCEPT ALONG THE SOUTH SHORE OF LAKE SUPERIOR WHERE LAKE
EFFECT SNOW SHOWERS WILL CONTINUE THROUGHOUT THE DAY. TEMPERATURES
WILL BARELY WARM UP TO THE UPPER TEENS TO LOW 20S.

STORM TOTAL SNOWFALL WILL BE IN THE 3-4 INCH RANGE ALONG THE NORTH
AND SOUTH SHORE REGIONS...WITH TO 3 INCHES ELSEWHERE. MOST OF THE
SNOWFALL WILL FALL MONDAY EVENING.

LAKE EFFECT SNOWFALL WILL BE IN THE 3-5 INCH RANGE ACROSS THE
GOGEBIC RANGE DEPENDING ON HOW LONG IT PERSISTS. WIND DIRECTION
BEGINS TO BACK BY TUESDAY AFTERNOON...SO UNLESS WINDS CAN PERSIST
OUT OF THE NORTH FOR LONGER THAN ANTICIPATED DO NOT EXPECT A
PROLONGED LAKE EFFECT EVENT.

FOR THE REST OF THE WEEK...PARTLY TO MOSTLY SUNNY SKIES...LIGHT
WINDS...AND SEASONABLE TEMPERATURES. HIGHS IN THE UPPER TEENS TO MID
20S...LOWS IN THE UPPER SINGLE DIGITS /ABOVE ZERO/ TO LOW TEENS. NO
MENTION OF PRECIP IN THE FORECAST...AND THE ONLY HOPE FOR ANY KIND
OF PRECIP IS A CLIPPER SYSTEM FOR SATURDAY INDICATED BY A FEW
MEMBERS OF THE GFS ENSEMBLE BUT OTHERWISE NOT BACKED UP BY THE REST
OF THE GUIDANCE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1135 PM CST SUN DEC 14 2014

AFTER SEVERAL DAYS OF SEEING VLIFR/LIFR CIGS AND VSBYS DUE TO FOG
AND DRIZZLE...WE WILL FINALLY SEE A TRANSITION TO A CHANGE IN
AIRMASS AS THE TAF PERIOD WEARS ON. A LOW PRESSURE SYSTEM WILL
MOVE OFF TO THE SOUTH AND EAST OF THE CWA...DRAWING COOLER AIR
FROM NW TO SE AS THE PERIOD WEARS ON. AS A RESULT...WE WILL SEE
RAIN AND DRIZZLE CHANGE TO SLEET AND SNOW...AND EVENTUALLY ALL
SNOW. SOME ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHEASTERN
LOCATIONS...NAMELY KDLH AND KHYR. CONDITIONS WILL GRADUALLY
RECOVER TO IFR AND POSSIBLY EVEN SOME MVFR BY THE END OF THE
PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  37  41  17  18 /  60  90  90  20
INL  32  34  10  15 /  60  40  20  10
BRD  36  38  16  19 /  60  70  70  10
HYR  41  47  23  23 /  60  80  90  50
ASX  37  44  24  24 /  60  90  90  60

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 3 PM MONDAY TO 6 AM CST TUESDAY FOR
     MNZ011-012-019>021-035>038.

     DENSE FOG ADVISORY UNTIL NOON CST MONDAY FOR MNZ010>012-018>021-
     025-026-033>038.

     WINTER WEATHER ADVISORY FROM 10 AM MONDAY TO MIDNIGHT CST MONDAY
     NIGHT FOR MNZ010-018-025-026-033-034.

WI...WINTER WEATHER ADVISORY FROM 3 PM MONDAY TO 6 AM CST TUESDAY FOR
     WIZ001-006.

     DENSE FOG ADVISORY UNTIL NOON CST MONDAY FOR WIZ001>004-006>009.

LS...SMALL CRAFT ADVISORY FROM 10 PM MONDAY TO 10 PM CST TUESDAY FOR
     LSZ121-146>148.

     SMALL CRAFT ADVISORY FROM 10 PM MONDAY TO 10 AM CST TUESDAY FOR
     LSZ140-141.

&&

$$

UPDATE...DAP
SHORT TERM...BJT
LONG TERM...JJM
AVIATION...DAP





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