386
FXUS63 KDLH 200544
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1144 PM CST THU DEC 19 2024
KEY MESSAGES
- PERIODS OF LIGHT TO MODERATE SNOW CONTINUE THE REST OF TODAY
INTO TONIGHT, WITH THE HIGHEST ADDITIONAL AMOUNTS EXPECTED
NEAR THE NORTH SHORE, TWIN PORTS, AND SOUTH SHORE WHERE
ADDITIONAL ACCUMULATIONS OF 2 TO 5 INCHES ARE POSSIBLE.
- A COLDER WEATHER PATTERN PERSISTS THROUGH SATURDAY NIGHT,
THEN WARMING UP SUNDAY INTO NEXT WEEK.
- A COUPLE ROUNDS OF ADDITIONAL LIGHT PRECIPITATION CHANCES
NEXT WEEK.
DISCUSSION
ISSUED AT 314 PM CST THU DEC 19 2024
REST OF TODAY - TONIGHT:
AS OF THIS AFTERNOON, REGIONAL RADAR AND OBSERVATIONS SHOWS
ONGOING LIGHT TO MODERATE SNOW FOR MUCH OF THE NORTHLAND, WITH
THE LIGHTEST RATES ACROSS FAR NORTHERN MN AND THE HIGHER RATES
(AROUND 0.25" TO LOCALLY 0.5"/HR) BEING PRIMARILY ALONG AND
SOUTH OF HIGHWAY 2 WHERE THE PRIMARY FRONTOGENETIC FORCING IS
LOCATED, AS WELL AS AREAS NEAR THE HEAD OF THE LAKE WHERE
ONSHORE FLOW IS LEADING TO LAKE-ENHANCEMENT.
OBSERVED SNOWFALL THROUGH MUCH OF TODAY HAS SEEN LOWER SNOW
RATES THAN WERE FORECAST FOR MUCH OF THE AREA AS THE BETTER
SYNOPTIC BANDING ASSOCIATED WITH LOW PRESSURE DIVING ACROSS THE
IOWA/MN BORDER WAS PAINED FROM WEST-CENTRAL THROUGH SOUTHEAST
MN. HREF/HI-RES GUIDANCE SHOWS LOWER RATES (0.1-0.25")
PERSISTING FOR THE REST OF THE AFTERNOON INTO MID-EVENING FOR
NORTH-CENTRAL AND NORTHEAST MN, WHILE LINGERING INTO THE
OVERNIGHT HOURS FOR NORTHWEST WI AS THE LOW PRESSURE EXITS
SOUTHEAST THROUGH NORTHERN ILLINOIS AND NORTHERN INDIANA. SNOW
SHOULD END FOR ALL BUT PORTIONS OF ASHLAND/IRON COUNTIES BY
FRIDAY MORNING.
OUTSIDE OF THE SYNOPTIC SNOW, LAKE-EFFECT/LAKE-ENHANCED SNOW
BECOMES THE MAIN FOCUS FOR PORTIONS OF THE NORTH SHORE AND TWIN
PORTS THROUGH THIS EVENING AND SOUTH SHORE THROUGH TONIGHT. AS
WINDS BEGIN TO TURN MORE NORTHEASTERLY LATER THIS AFTERNOON INTO
EARLY EVENING, HI-RES MODELS POINT TO A LAKE-EFFECT/CONVERGENCE
BAND DEVELOPING AND SHIFTING SOUTHWARD FROM SOUTHERN LAKE COUNTY
INTO THE TWIN PORTS. FURTHERMORE, AS WINDS SHIFT TO NORTHERLY
LATER THIS EVENING AND TONIGHT, THIS SNOW BAND SHOULD SHIFT
INTO THE SOUTH SHORE. WHILE SNOW RATES WITH THIS SNOW BAND COULD
LOCALLY EXCEED 0.5"/HR, THE BAND IS EXPECTED TO BE TRANSIENT IN
NATURE DUE TO WIND SHIFTS, LEADING TO IT ONLY BEING BRIEFLY
PRESENT OVER ANY LOCATION FOR A FEW HOURS AT MOST.
SO HOW DO ALL OF THESE RATES TRANSLATE INTO ADDITIONAL SNOWFALL
AMOUNTS? WELL, GENERALLY SPEAKING THIS MEANS AN ADDITIONAL FEW
TENTHS OF AN INCH NEAR THE INTERNATIONAL BORDER TO AROUND 1" IN
THE IRON RANGE. AREAS ALONG AND SOUTH OF U.S. HIGHWAY 2 FROM
CENTRAL MN INTO NORTHWEST WI COULD SEE AN ADDITIONAL 1-2", WITH
THE HIGHEST OF THESE AMOUNTS IN NORTHWEST WI WHERE SNOW LINGERS
THE LONGEST. FOR THE NORTH SHORE, ADDITIONAL ACCUMULATIONS
THROUGH THIS EVENING OF 1-4" ARE FORECAST, WITH THE HIGHEST
AMOUNTS IN THE HIGHER TERRAIN FROM SILVER BAY TO DULUTH GIVEN
THE STRONGER INTENSITY OF THE LAKE-CONVERGENCE BAND THERE. FOR
THE SOUTH SHORE COUNTIES, THIS MEANS AN ADDITIONAL 2-5" OF
SNOWFALL, MOST OF WHICH WILL FALL THIS EVENING INTO TONIGHT,
THOUGH THE HIGHEST OF THESE ACCUMULATIONS WILL BE IN THE
NORTHERN PORTIONS OF DOUGLAS, BAYFIELD, ASHLAND, AND IRON
COUNTIES GIVEN PROXIMITY TO LAKE SUPERIOR AND SOME TERRAIN
ENHANCEMENT.
THE WINTER WEATHER ADVISORIES IN NORTH-CENTRAL AND
NORTHWEST MN AWAY FROM LAKE SUPERIOR WERE CANCELLED DUE TO THE
LOWER ADDITIONAL FORECAST SNOWFALL AMOUNTS AND RATES. MEANWHILE,
THE NORTHWEST WI COUNTIES AWAY FROM THE LAKE REMAIN IN WINTER
WEATHER ADVISORIES INTO EARLY TONIGHT. ALL OF THE WINTER STORM
WARNINGS ALONG THE NORTH SHORE TO DULUTH AREA AND IN BAYFIELD
COUNTY WERE DOWNGRADED TO WINTER WEATHER ADVISORIES DUE TO STORM
TOTAL SNOWFALL FROM THIS EVENT NO LONGER BEING EXPECTED TO
EXCEED 6-7". WINTER WEATHER ADVISORIES IN DOUGLAS, ASHLAND, AND
IRON COUNTIES REMAIN IN EFFECT, AS WELL. AS WINDS BECOME
NORTHWEST BY LATE FRIDAY MORNING, SNOW SHOULD ALSO COME TO AN
END ALONG THE SOUTH SHORE.
FRIDAY - SATURDAY:
COLDER ARCTIC AIR MOVES INTO THE REGION FOR FRIDAY INTO FRIDAY
NIGHT BEHIND THE DEPARTING LOW PRESSURE. THIS IS DESPITE EVEN
SEEING SUNSHINE FOR MUCH OF THE NORTHLAND ON FRIDAY. FRIDAY
MORNING LOWS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO AND WIND
CHILLS IN THE SINGLE DIGITS TO TEENS BELOW ZERO ARE FORECAST,
ASIDE FROM VALUES AROUND 5F WARMER IN NORTH-CENTRAL WI. SIMILAR
WIND CHILLS ARE EXPECTED BY EARLY SATURDAY MORNING DESPITE LOWS
BEING ABOUT 5F COOLER THAN FRIDAY MORNING. ADDITIONALLY, A VERY
WEAK CLIPPER COULD BRING A STRIPE OF FLURRIES/VERY LIGHT SNOW
(ACCUMULATIONS LESS THAN 0.5") TO PARTS OF NORTH-CENTRAL MN AND
THE BRAINERD LAKES FRIDAY NIGHT INTO SATURDAY, BUT CHANCES OF
SEEING ACCUMULATING SNOW WITH THIS SYSTEM ARE LESS THAN 20%.
SUNDAY - MONDAY:
TEMPERATURES BEGIN TO WARM BACK ABOVE NORMAL FOR THIS TIME OF
YEAR ON SUNDAY AS WINDS TURN SOUTHERLY AHEAD OF A CLIPPER SYSTEM
EJECTING OUT OF THE NORTHERN U.S. ROCKIES. STILL A BIT OF SPREAD
WITH REGARDS TO THE TIMING AND PRECIPITATION OUTPUT FROM THIS
SYSTEM FOR THE NORTHLAND SUNDAY NIGHT INTO MONDAY, BUT MOST
GLOBAL ENSEMBLES HAVE IT PAINTING AT LEAST SOME PORTION OF THE
NORTHLAND WITH MEASURABLE LIGHT SNOW. 850 MB TEMPERATURES WITH
THIS SYSTEM MAY NOT BE SUFFICIENT ENOUGH FOR TRUE LAKE-EFFECT
SNOW (LAKE SUPERIOR TO 850 MB TEMPERATURE DIFFERENCES OF
8-10C), THIS COULD AT LEAST LEAD TO SOME SLIGHT LAKE-ENHANCEMENT
OF SNOWFALL RATES DEPENDING ON HOW SURFACE WINDS BECOME
ORIENTED. HIGH TEMPERATURES REACH THE MID TO UPPER 20S ON SUNDAY
AND UPPER 20S TO MID 30S ON MONDAY.
CHRISTMAS TRAVEL OUTLOOK:
GLOBAL ENSEMBLES POINT TO A MID/UPPER LEVEL RIDGE SETTING UP
OVER THE CENTRAL U.S. FOR THE TUESDAY-WEDNESDAY TIMEFRAME, WHICH
WOULD GIVE THE NORTHLAND CONTINUED ABOVE-AVERAGE HIGH
TEMPERATURES IN THE 30S FOR TUESDAY THROUGH MOST OF NEXT WEEK,
AND DRIER WEATHER FOR TUESDAY AND WEDNESDAY. THERE ARE SOME
SIGNS THAT THE RIDGE BREAKS DOWN LATE NEXT WEEK INTO NEXT
WEEKEND, LEADING TO A RETURNING POTENTIAL FOR PRECIPITATION WITH
A SERIES OF SHORTWAVES. GIVEN THE WARMER TEMPERATURES, SOME OF
THIS PRECIPITATION COULD EVEN FALL AS A MIX OR IN LIQUID FORM.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1143 PM CST THU DEC 19 2024
LIGHT SNOW WAS DIMINISHING OVER NORTHERN MINNESOTA BUT WAS STILL
WIDESPREAD OVER NORTHWEST WISCONSIN. THE SOUTH SHORE WILL SEE HEAVIER
SNOW DUE TO LAKE PROCESSES WITH VISIBILITY REDUCTIONS TO A HALF
MILE AND SNOWFALL RATES OF A HALF TO ONE INCH PER HOUR IN A
BAND OF SNOW MOVES THROUGH. THE HEAVIER SNOW BAND IS EXPECTED TO
BE MOVING, ONLY STAYING OVER ANY ONE LOCATION FOR 1 TO 3 HOURS.
AS THE SNOW DIMINISHES CEILINGS HAVE IMPROVED TO LOW VFR OVER
MANY LOCALES. THAT TREND IS EXPECTED TO CONTINUE. HOWEVER, THERE
ARE SOME INDICATIONS THAT AS CLOUDS CLEAR OR THIN THAT IFR
CEILINGS MAY FORM. THE HREF/SREF CONTINUE TO SUGGEST THAT WON'T
HAPPEN WITH CHANCES AT LESS THAN 30%. FOR NOW, WE JUST ADDED A
MENTION OF IFR CEILINGS LATER TONIGHT INTO FRIDAY BUT WILL
MONITOR UPSTREAM OBSERVATIONS AND SATELLITE.
WINDS WILL BACK TO NORTH THEN NORTHWEST TONIGHT INTO FRIDAY AND
DECREASE ON FRIDAY AS HIGH PRESSURE BUILDS IN.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 314 PM CST THU DEC 19 2024
NORTHEAST WINDS THIS AFTERNOON BECOME NORTHERLY TONIGHT, WITH
GUSTS INCREASING TO 20 TO 30 KT THIS EVENING INTO FRIDAY
MORNING. WAVE HEIGHTS UP TO 4 TO 7 FT ARE ALSO FORECAST TO
DEVELOP ALONG THE SOUTH SHORE AS WINDS TURN MORE NORTHERLY.
SNOW WILL CONTINUE THROUGH THIS PERIOD AS WELL.
WIND GUSTS DROP BELOW 20 KT OUT OF THE NORTHWEST FRIDAY INTO
FRIDAY NIGHT, THEN SOUTHERLY THROUGH THE WEEKEND. THERE COULD
BE SOME LOCALLY BREEZY CONDITIONS FOR PARTS OF THE NORTH SHORE
ON SUNDAY WITH GUSTS APPROACHING 20 TO 25 KT.
FOR THE OPEN WATER DISCUSSION, REFER TO THE NWS MARQUETTE AREA
FORECAST DISCUSSION AT WEATHER.GOV/MQT.
DLH WATCHES/WARNINGS/ADVISORIES
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ020-
037.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST FRIDAY FOR WIZ001-002.
WINTER WEATHER ADVISORY UNTIL 9 AM CST FRIDAY FOR WIZ003-004.
WINTER WEATHER ADVISORY UNTIL 3 AM CST FRIDAY FOR WIZ006>009.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM CST FRIDAY FOR LSZ121-146>148-
150.
SMALL CRAFT ADVISORY UNTIL 9 AM CST FRIDAY FOR LSZ140>143.
SMALL CRAFT ADVISORY UNTIL 6 AM CST FRIDAY FOR LSZ144-145.
DISCUSSION...ROTHSTEIN
AVIATION...MELDE
MARINE...ROTHSTEIN
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