811
FXUS63 KDLH 181749
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1149 AM CST WED DEC 18 2024
KEY MESSAGES
- LIGHT LAKE EFFECT SNOW WILL CONTINUE THIS MORNING FOR
NORTHERN IRON COUNTY, THEN SLOWLY DIMINISH.
- A CLIPPER WILL BRING HEAVIER SNOW LATE TONIGHT THROUGH
THURSDAY NIGHT, WHICH WILL LEAVE A WIDE PATH OF ACCUMULATING
FROM THE BRAINERD LAKES AREA EAST ACROSS NORTHWEST WISCONSIN.
MOST AREAS ARE LOOKING AT 3 TO 6 INCHES OF SNOW. LAKE EFFECT
MAY BRING LOCALLY HIGHER VALUES TO PORTIONS OF THE NORTH AND
SOUTH SHORES.
- COLDER TEMPERATURES WILL MOVE IN FOR FRIDAY AND SATURDAY, BUT
THESE WILL BE NEAR TO BELOW NORMAL.
- THERE IS A LOW CONFIDENCE CHANCE OF SNOW FOR EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 455 AM CST WED DEC 18 2024
STEEP LOW LEVEL LAPSE RATES THIS MORNING HAVE PRODUCED A FAIRLY
LARGE AREA OF LIGHT SNOW SHOWERS OR FLURRIES TO THE NORTHLAND
OVERNIGHT. IN COMBINATION WITH LAKE EFFECTS, THERE ARE LIKELY
SOME LIGHT ACCUMULATIONS ALONG THE SOUTH SHORE SNOWBELT REGIONS.
BOTH THE SNOW SHOWERS AND LAKE EFFECTS SHOULD GRADUALLY
DIMINISH TODAY AS A RIDGE OF HIGH PRESSURE PUSHES ACROSS THE
REGION TODAY.
TONIGHT THROUGH THURSDAY NIGHT A BEEFY CLIPPER SYSTEM WILL DIVE
ACROSS THE AREA, MOVING FROM THE MONTANA/CANADIAN BORDER REGION
EAST-SOUTHEAST ACROSS THE PLAINS TO NORTHERN IOWA, THEN ON TO
NORTHERN INDIANA BY FRIDAY MORNING. THIS SYSTEM SHOULD PLACE A
PATH OF MODERATE TO HEAVY SNOWFALL ACROSS CENTRAL MINNESOTA INTO
NORTHERN WISCONSIN BEGINNING LATE THIS EVENING, CONTINUING
THROUGH THURSDAY BEFORE ENDING THURSDAY NIGHT. WHILE THE
SNOWFALL PROBABILITIES FOR 4 INCHES OR MORE HAVE BEEN DROPPING
IN THE PREVIOUS FORECASTS, WE ARE NOW WITHIN RANGE FOR THE
HIGHER RESOLUTION MODELS TO CHIME IN, WHICH HAS BROUGHT OUR QPF
VALUES UP, AND ALSO THE SNOWFALL ACCUMULATIONS UP WITH THIS
FORECAST. THE HIGH RESOLUTION MODELS HAVE ALSO PICKED UP ON OUR
LAKE EFFECTS, WHICH ALSO TENDS TO REALLY BOOST SNOWFALL RATES
AND EVENTUAL ACCUMULATIONS. WITH THESE CHANGES, WE NOW HAVE A
MUCH HIGHER PROBABILITY OF 60 TO 80% OF 4 INCHES OR MORE ACROSS
THE SOUTHERN FORECAST AREA, AND THEN ALONG THE NORTH SHORE WHERE
THE EASTERLY FLOW DURING THE DAY ON THURSDAY WILL TARGET LAKE
EFFECT SNOWFALL OF ALSO IN THE 60 TO 80% RANGE. A QUICK CHECK OF
OUR CLIMATOLOGY INDICATES WE WILL BE APPROACHING A RECORD DAILY
SNOWFALL FOR DULUTH SHOULD THE CURRENT FORECAST WORK OUT. THIS
SYSTEM IS NOW MUCH MORE INTERESTING THAN IT WAS YESTERDAY. WITH
THAT SAID, THIS INCREASE IN SNOWFALL AMOUNTS IS CONCERNING AND
DUE TO CONFIDENCE ISSUES HAVE DECIDED TO ISSUE A WINTER STORM
WATCH ALONG THE NORTH SHORE AND ALSO FOR DOUGLAS AND BAYFIELD
COUNTIES FOR A NOT INSIGNIFICANT RISK OF 8 INCHES OR MORE,
DEPENDING ON WHERE THE LES BANDS SET UP. I HAVE ALSO ISSUED AN
SPS DISCUSSING THIS SNOWFALL FOR THURSDAY FOR AREAS ALONG AND
SOUTH OF HIGHWAY 2.
BEHIND THIS CLIPPER WE ARE GOING TO GET A SHOT OF COLDER AIR,
WITH OVERNIGHT LOW TEMPERATURES DIPPING NEAR TO BELOW ZERO FOR
MUCH OF THE AREA BY THURSDAY NIGHT AND FRIDAY NIGHT. IN FACT,
FRIDAY NIGHT MAY BE OUR COLDEST NIGHT AS A HIGH PRESSURE RIDGE
BUILDS INTO THE AREA. SHOULD WE LOSE CLOUD COVER, WHICH LOOKS
MOST LIKELY FOR THE TIP OF THE ARROWHEAD, THE FRESH SNOW WILL
PRODUCE EXCELLENT RADIATIONAL COOLING CONDITIONS. HOWEVER, THE
CLOUD COVER IS A BIG QUESTION MARK AT THIS POINT AND HAVE LEFT
OVERNIGHT LOWS ONLY A LITTLE BELOW NORMAL FOR NOW.
EARLY NEXT WEEK THE MODELS ARE BRINGING A SHORTWAVE ACROSS THE
AREA, WITH THE POTENTIAL TO BRING ACCUMULATING SNOW TO THE
NORTHLAND. THE TRACK AND STRENGTH OF THIS FEATURE IS QUITE
VARIABLE BETWEEN MODELS. CONFIDENCE IN TIMING AND TRACK IS LOW,
SO PRECIPITATION CHANCES REMAIN LOW FOR NOW, AND TEMPERATURES
SHOULD BE NEAR TO ABOVE NORMAL.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1148 AM CST WED DEC 18 2024
A MIX OF MVFR AND VFR CEILINGS THIS AFTERNOON AS LOW STRATUS
SCATTERS OUT AND CLEARS FROM NORTHWEST TO SOUTHEAST WITH A
RETURN TO VFR LATE THIS AFTERNOON AND EVENING. STILL SOME LIGHT
FLURRIES/SNOW AROUND KBRD AND KHYR, BUT THAT TOO SHOULD CLEAR
LATER THIS AFTERNOON. SNOW MAKES A RETURN TONIGHT THROUGH MUCH
OF THURSDAY AS A POTENT CLIPPER SYSTEM MOVES THROUGH THE
NORTHLAND. MVFR CEILINGS RETURN STARTING TONIGHT, THOUGH KBRD
MIGHT SEE IFR CEILINGS BY THURSDAY MORNING. MVFR TO IFR
CONDITIONS IN THE SNOW EXPANDS ACROSS THE NORTHLAND IN THE
MORNING, WITH SOME LIFR VISIBILITIES IN HEAVIER SNOW MOST LIKELY
FOR KDLH AND KBRD DURING THURSDAY MORNING. NORTHWEST WINDS VEER
TO EAST- SOUTHEASTERLY TONIGHT INTO TOMORROW WITH WIND GUSTS
INCREASING TO 15-25 KNOTS, HIGHEST AT KHYR AND KBRD.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 455 AM CST WED DEC 18 2024
NORTHWEST WINDS GUSTING UP TO 30 KNOTS EARLY THIS MORNING TO
SLOWLY, SLOWLY DIMINISH DURING THE DAY TODAY, CAUSING WAVES TO
BE BUILT UP ALONG THE SOUTH SHORE. I HAVE EXPANDED THE SMALL
CRAFT ADVISORY FOR TODAY TO AROUND THE APOSTLE ISLANDS WHERE WE
HAVE BOTH THE STRONG WINDS AND THE BUILT UP WAVES. ANOTHER
CLIPPER SYSTEM PASSING THROUGH THE AREA THURSDAY THROUGH FRIDAY
IS LIKELY TO CAUSE ANOTHER PERIOD OF HAZARDOUS CONDITIONS ON THE
LAKE. WINDS WILL INCREASE OUT OF THE EAST TO NORTHEAST ON
THURSDAY, THEN SLOWLY BACK INTO THE NORTHEAST TO NORTH THURSDAY
NIGHT, AND FINALLY TO NORTHWEST FOR FRIDAY. FOR NOW WIND SPEEDS
IN THE 20 TO 30 KNOT RANGE ARE EXPECTED, BUT THERE MAY BE BRIEF
PERIODS OF GALE FORCE GUSTS.
FOR THE OPEN WATER DISCUSSION, REFER TO THE NWS MARQUETTE AREA
FORECAST DISCUSSION AT WEATHER.GOV/MQT.
DLH WATCHES/WARNINGS/ADVISORIES
MN...WINTER STORM WATCH FROM LATE TONIGHT THROUGH THURSDAY EVENING
FOR MNZ020-021-037.
WI...WINTER STORM WATCH FROM LATE TONIGHT THROUGH THURSDAY EVENING
FOR WIZ001-002.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR
LSZ140>142-150.
DISCUSSION...LE
AVIATION...ROTHSTEIN
MARINE...LE
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