307
FXUS63 KDLH 161152
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
552 AM CST MON DEC 16 2024
KEY MESSAGES
- DENSE FOG LINGERING FROM CLOQUET UP THE HIGHER TERRAIN OF THE
NORTH SHORE THROUGH MID MORNING.
- A CLIPPER SYSTEM WILL BRING AN INITIAL WINTRY MIX THIS
MORNING, TRANSITIONING TO SNOW THROUGH THE REST OF TODAY AND
EARLY EVENING BEFORE ENDING OVERNIGHT. LIGHT ACCUMULATIONS OF
UP TO 2" FOR FAR NORTHERN MINNESOTA.
- COLDER TEMPERATURES RETURN FOR TUESDAY THROUGH NEXT WEEKEND.
- A MORE POTENT CLIPPER SYSTEM IS EXPECTED ON THURSDAY WITH
ACCUMULATING SNOW INCREASINGLY LIKELY.
DISCUSSION
ISSUED AT 437 AM CST MON DEC 16 2024
A BROAD AREA OF DRIZZLE/FREEZING DRIZZLE AND FOG UNDER STRATUS
IS AFFECTING THE AREA THIS MORNING AS A LOW PRESSURE SYSTEM OVER
SOUTHEAST MANITOBA MOVES EAST INTO ONTARIO TODAY. A COLD FRONT
WHICH WILL FOLLOW THIS SYSTEM IS NOW MOVING ACROSS NORTH DAKOTA,
WHICH SHOULD PUSH ACROSS THE FORECAST AREA TONIGHT. AS THIS
SYSTEM MOVES EAST THE STRATUS, DRIZZLE AND FOG SHOULD ALSO PUSH
EAST. AS COLDER AIR MOVES IN BEHIND THE LOW PRESSURE SYSTEM WE
SHOULD SEE AN EVENTUAL SWITCH OVER TO LIGHT SNOW INSTEAD OF THE
FREEZING DRIZZLE, AND THERE WILL BE SOME LIGHT ACCUMULATIONS
TODAY AND THIS EVENING, MAINLY ALONG AND NORTH OF HWY 2. UP TO 2
INCHES ARE POSSIBLE ALONG THE US/CANADA BORDER, THOUGH THESE
AMOUNTS HAVE DECREASED SLIGHTLY WITH THIS SET OF MODEL RUNS.
BACK AROUND MIDNIGHT AND EARLIER IN THE EVENING, THE SOUTHERLY
WINDS WERE CAUSING SOME UPSLOPE FLOW ALONG THE NORTH SHORE,
PRODUCING DENSE FOG ALONG THE HIGHER TERRAIN, WITH KDLH AND KCKC
BOTH IN THE PEA SOUP OF FOG. HOWEVER, AS THE LOW HAS MOVED
FARTHER EAST, THE WIND DIRECTIONS HAVE BEGUN VEERING MORE
SOUTHWESTERLY, AND WE HAVE SEEN VISIBILITIES IMPROVE AT LEAST
HERE AROUND THE TWIN PORTS, BUT VISIBILITIES REMAIN VERY POOR
FARTHER NORTH ALONG THE NORTH SHORE. HAVE DECIDED TO LEAVE THE
DENSE FOG ADVISORY IN PLACE AS IS, BUT WE MAY BE ABLE TO CANCEL
ALL/PARTS OF THE ADVISORY EARLY AS THIS TREND CONTINUES.
BEHIND THIS SYSTEM WE GET INTO A FAIRLY STRONG NORTHWEST FLOW
REGIME, WITH GUSTY NORTHWEST WINDS EXPECTED ON TUESDAY AND
TEMPERATURES COOLING OFF TOWARD NORMAL. A CLIPPER SYSTEM MOVES
ACROSS SOUTHERN MN INTO WI ON TUESDAY, BUT MISSING THE NORTHLAND
FOR THE MOST PART. I WOULD NOT BE TOO SURPRISED IF WE HAVE SOME
LINGERING FLURRIES IN THE COLD AIR ADVECTION AND WITH STEEP LOW
LEVEL LAPSE RATES, BUT WE MAY NOT HAVE ENOUGH MOISTURE AND HAVE
LEFT THIS OUT FOR NOW. WE GET A TRAILING, WEAKER SHORTWAVE FOR
WEDNESDAY, THAT TOGETHER WITH THE NORTHWEST FLOW SHOULD TURN ON
THE LAKE EFFECT MACHINE FOR TUESDAY NIGHT INTO WEDNESDAY FOR THE
SOUTH SHORE.
ATTENTION THEN TURNS TO THE MUCH STRONGER CLIPPER THAT SHOULD
MOVE THROUGH THE AREA ON THURSDAY. WE STILL HAVE A LOT OF SPREAD
ON THE TRACK OF THIS SYSTEM, WHICH OF COURSE IS PRODUCING QUITE
THE SPREAD IN POTENTIAL SNOWFALL AMOUNTS. SCARILY ENOUGH, THERE
ARE MEMBERS IN BOTH THE ECMWF AND GEFS ENSEMBLE SUITES WHICH
PRODUCE SEVERAL INCHES OF SNOWFALL FOR THE SOUTHERN HALF OF THE
FORECAST AREA, BUT THERE ARE ALSO MEMBERS WHICH ARE DRY. FOR
NOW, CONFIDENCE REMAINS LOW, BUT IF THE MEANS WORK OUT, WE ARE
LOOKING AT A BAND OF SNOW THAT WILL NEED TO BE SHOVELED/PLOWED
ON THURSDAY SOMEWHERE IN THE NORTHLAND. THIS SYSTEM SHOULD ALSO
HAVE A PERIOD OF LAKE EFFECT SNOW WHICH LINGERS INTO AT LEAST
FRIDAY.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 551 AM CST MON DEC 16 2024
A CLIPPER SYSTEM MOVING ACROSS THE AREA THIS TAF PERIOD WILL
KEEP FLYING CONDITIONS POOR. PREDOMINANTLY IFR/LIFR CONDITIONS
IN FOG AND STRATUS THIS MORNING. CEILINGS LIKELY TO REMAIN IFR
TODAY, BUT VISIBILITIES MAY IMPROVE TO MVFR AS FOG SLOWLY
DISSIPATES AS WINDS BECOME WESTERLY. SNOW TO AFFECT MAINLY KINL,
KHIB AND KDLH, WITH VISIBILITIES DROPPING BACK TO IFR FOR A FEW
HOURS THIS AFTERNOON BEFORE IMPROVING AGAIN AS THE SNOW ENDS
FROM SOUTHWEST TO NORTHEAST THIS EVENING. WESTERLY WINDS ARE
EXPECTED TO GRADUALLY INCREASE IN SPEED WITH GUSTS 15 TO 20 KT
WITH COLD AIR MOVING IN. VISIBILITIES TO IMPROVE TO VFR FOR ALL
TERMINALS BY 06Z TONIGHT, THOUGH THE IFR/MVFR CEILINGS TO LINGER
THROUGH THE REMAINDER OF THE TAF PERIOD.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 437 AM CST MON DEC 16 2024
A CLIPPER SYSTEM MOVING THROUGH THE AREA TODAY WILL TAKE THE
CURRENT SOUTH-SOUTHWEST WINDS OVER THE LAKE AND CAUSE THEM TO
GRADUALLY VEER THROUGH THE WEST TODAY TO NORTHWEST TONIGHT INTO
TUESDAY. WIND GUSTS UP TO 25 TO 30 KT ARE EXPECTED TO DEVELOP,
AND SOME GALES TO 35 KT ARE POSSIBLE IN THE OUTER APOSTLE
ISLANDS AND ROUGHLY FROM PORT WING TO BAYFIELD ALONG THE
PENINSULA THIS AFTERNOON INTO TONIGHT. ADDITIONALLY, WINDS ARE
FORECAST TO PICK UP TO GALES OF 35 KNOTS ALONG THE NORTH SHORE
LATE THIS EVENING INTO EARLY TUESDAY MORNING DUE TO ACCELERATING
WINDS DOWN THE SLOPES OF THE NORTH SHORE TERRAIN. GALE WARNINGS
ARE IN EFFECT THIS EVENING INTO EARLY TUESDAY WHERE WIND GUSTS
TO 35 KNOTS ARE FORECAST. WAVE HEIGHTS AROUND 4 TO 8 FEET ARE
ALSO EXPECTED IN THIS TIME PERIOD ALONG WITH LIGHT/RAIN SNOW
CHANGING TO SNOW MONDAY NIGHT. AFTER THE CLIPPER SYSTEM PASSES
THROUGH ON TUESDAY, NORTHWEST WINDS AND WAVES ARE EXPECTED TO
DECREASE ON TUESDAY AFTERNOON.
FOR THE OPEN WATER DISCUSSION, REFER TO THE NWS MARQUETTE AREA
FORECAST DISCUSSION AT WEATHER.GOV/MQT.
DLH WATCHES/WARNINGS/ADVISORIES
MN...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ020-021-
037.
WI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM CST TUESDAY FOR LSZ121-143>145-
148.
SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR
LSZ140>142.
GALE WARNING FROM 9 PM THIS EVENING TO 9 AM CST TUESDAY FOR
LSZ140>142.
SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR LSZ146-
147-150.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 9 AM CST TUESDAY FOR
LSZ146-147-150.
DISCUSSION...LE
AVIATION...LE
MARINE...LE
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