438
FXUS63 KDLH 190554
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1154 PM CST WED DEC 18 2024
KEY MESSAGES
- VERY LIGHT SNOW IN NORTHWEST WISCONSIN ENDING THIS AFTERNOON.
- A POTENT CLIPPER WILL BRING HEAVIER SNOW LATE TONIGHT THROUGH
THURSDAY NIGHT. THIS WILL LEAVE A WIDE PATH OF 3 TO 6 INCHES
OF SNOW ACROSS MUCH OF THE NORTHLAND, WITH THE HIGHEST AMOUNTS
FROM THE BRAINERD LAKES INTO PARTS OF NORTHWEST WISCONSIN.
LAKE EFFECT WILL BRING LOCALLY HIGHER VALUES TO PORTIONS OF
THE NORTH AND SOUTH SHORES.
- COLDER TEMPERATURES WILL MOVE IN FOR FRIDAY AND SATURDAY, WITH
MORNING WIND CHILLS IN THE SINGLE DIGITS TO TEENS BELOW ZERO
FOR MOST LOCATIONS.
- THERE IS A LOW CONFIDENCE CHANCE (20-40%) OF SNOW FOR EARLY
NEXT WEEK.
DISCUSSION
ISSUED AT 342 PM CST WED DEC 18 2024
REST OF TODAY:
LIGHT SNOW OVER PORTIONS OF NW WI WILL BE ENDING LATER THIS
AFTERNOON AS A BRIEF ROUND OF HIGH PRESSURE MOVES OVERHEAD
THROUGH THIS EVENING. LITTLE TO NO ADDITIONAL ACCUMULATIONS
EXPECTED. WE HAVE ALSO SEEN SUNSHINE SPREAD ACROSS MUCH OF THE
NORTHLAND THIS AFTERNOON ASSOCIATED WITH THE HIGH PRESSURE.
THIS TOO WILL BE SHORTLIVED AS A POTENT CLIPPER SYSTEM MOVES
INTO THE REGION TONIGHT, WITH CLOUD COVER INCREASING AGAIN THIS
EVENING AS IT DOES.
WIDESPREAD ACCUMULATING SNOW TONIGHT-THURSDAY NIGHT:
FOR TONIGHT THROUGH THURSDAY NIGHT, THE AFOREMENTIONED CLIPPER
WILL BE TREKKING SOUTHEASTWARDS FROM THE MONTANA/SASKATCHEWAN
BORDER THROUGH THE DAKOTAS AND MINNESOTA/IOWA BORDER BEFORE
EXITING TO NORTHERN INDIANA BY FRIDAY MORNING. THE OVERALL TRACK
OF THE SYSTEM HAS SHIFTED SLIGHTLY FARTHER SOUTH THAN THE
PREVIOUS FORECAST, BUT NOT SUBSTANTIALLY SO. DESPITE BEING A
CLIPPER SYSTEM, THIS SYSTEM HAS SEVERAL THINGS GOING FOR IT TO
CREATE A SWATH OF MODERATE TO HEAVIER SNOWFALL TOTALS ACROSS
MUCH OF THE NORTHLAND RELATIVE TO WHAT WE TYPICALLY SEE WITH
CLIPPERS. A DEEP, SATURATED DENDRITIC GROWTH ZONE WILL ALLOW
FOR THE EFFICIENT PRODUCTION OF FLUFFIER SNOW GIVEN SNOW RATIOS
AROUND 16 TO 20:1 FOR MUCH OF THE SNOWFALL DURATION. FOR
LOCATIONS GENERALLY FROM THE BRAINERD LAKES TO HINCKLEY AND
PARTS OF NW WI, PROXIMITY TO MORE FAVORABLE FRONTOGENETIC
FORCING FOR LIFT IN THE DENDRITIC GROWTH ZONE SHOULD AID IN
INCREASED SNOWFALL RATES ON THE ORDER OF 0.5-0.75"/HR WITH THE
HIGHEST RATES COMING DURING THE LATE OVERNIGHT HOURS TONIGHT
THROUGH THE MORNING COMMUTE (I.E. AROUND 4/5AM TO 10/11 AM). FOR
THE TWIN PORTS INTO THE NORTH SHORE, EASTERLY WINDS OFF OF THE
LAKE AND HIGHER TERRAIN SHOULD ALSO PAINT A PERIOD OF 0.5-1"/HR
SNOWFALL RATES FROM AROUND 6/7 AM THROUGH THE EARLY AFTERNOON,
BUT IMPACTS FROM THE SNOW THAT FALLS UP TO THAT POINT AND
LINGERING LIGHTER SNOW SHOULD ALSO CREATE IMPACTS FOR THE
EVENING COMMUTE AS WELL. AS THE LOW PRESSURE SYSTEM CONTINUES
TRACKING SOUTHEAST, WINDS WILL BEGIN TO SHIFT AROUND TO
NORTHERLY THURSDAY EVENING INTO THURSDAY NIGHT, WHICH WILL PUSH
THE LAKE- ENHANCED SNOWFALL RATES INTO THE SOUTH SHORE. AS THIS
IS ONGOING, THE SNOWFALL RATES ACROSS THE REMAINDER OF THE
NORTHLAND SHOULD BECOME LIGHTER THURSDAY EVENING AND NIGHT, WITH
SNOWFALL ENDING FROM WEST TO EAST BY EARLY FRIDAY MORNING FOR
ALL BUT FAR NORTHERN ASHLAND AND IRON COUNTIES WHERE LIGHTER
LAKE-EFFECT WILL LINGER INTO THE FRIDAY MORNING COMMUTE.
WITH ALL THIS SAID, LETS TALK ABOUT SNOWFALL TOTALS. FORECAST
SNOWFALL AMOUNTS HAVE INCREASED SUBSTANTIALLY OVER THE LAST 24
HOURS. AREAS ALONG AND SOUTH OF U.S. HIGHWAY 2 WILL GENERALLY
SEE SNOW ACCUMULATIONS OF 3-6 INCHES, WITH MEDIUM CONFIDENCE IN
LOCALLY HIGHER AMOUNTS 6-8" FROM THE BRAINERD LAKES INTO THE
I-35 CORRIDOR AND INTO PARTS OF NORTHWEST WISCONSIN. LOCALES
NEAR LAKE SUPERIOR FROM TOFTE SOUTH TO THE TWIN PORTS AND IN THE
BAYFIELD PENINSULA TO NORTHERN IRON COUNTY COULD ALSO SEE
LOCALLY 6-8" SNOW AMOUNTS, WITH SOME MORE SPARSE POCKETS OF 8+
INCHES IN HIGHER TERRAIN. AMOUNTS DROP OFF FARTHER UP THE NORTH
SHORE TO 1-4" FOR GRAND MARAIS TO GRAND PORTAGE, AS WELL AS 2-4"
FOR THE IRON RANGE AND 1-3" FOR THE BORDERLANDS. WINTER WEATHER
ADVISORIES AND WINTER STORM WARNINGS ARE IN EFFECT FOR PORTIONS
OF THE NORTHLAND, WITH THE WINTER STORM WARNINGS ISSUED FOR
AREAS WHERE CONFIDENCE IS HIGHEST IN SEEING 6+" OF SNOWFALL FOR
TONIGHT THROUGH THURSDAY NIGHT.
FRIDAY-THIS WEEKEND:
CONDITIONS TURN PREDOMINATELY DRIER AND COLDER FOR FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE SLIDES THROUGH
NORTHWEST/NORTHERN ONTARIO, WITH SOME SUNSHINE EVEN MIXING IN AT
TIMES! ONE THING TO KEEP AN EYE ON IS JUST HOW MUCH CLEARING WE
CAN GET, PARTICULARLY ON FRIDAY NIGHT, AS THE FRESH SNOW COVER
COULD LEAD TO AN EFFICIENT RADIATIONAL COOLING SET-UP AND DROP
LOW TEMPERATURES FURTHER THAN THE CURRENT FORECAST. GENERALLY
SPEAKING, LOOK FOR LOWS IN THE SINGLE DIGITS ABOVE AND BELOW
ZERO FOR MOST, WITH WIND CHILLS IN THE SINGLE DIGITS TO TEENS
BELOW ZERO BOTH FRIDAY AND SATURDAY MORNINGS. A SHIFT TO
SOUTHEASTERLY SURFACE WINDS SHOULD MODERATE TEMPERATURES FOR
SUNDAY, WITH MORNING LOWS IN THE SINGLE DIGITS ABOVE ZERO AND
HIGHS IN THE 20S.
SNOW CHANCES AND WARMING UP EARLY NEXT WEEK:
GLOBAL ENSEMBLES POINT TO A SHORTWAVE TRAVERSING THE UPPER
MIDWEST ON MONDAY, WHICH COULD BRING ACCUMULATING SNOW TO THE
NORTHLAND. THERE'S STILL SOME DECENT SPREAD IN THE GUIDANCE
REGARDING THE TRACK, STRENGTH, AND TIMING OF THIS FEATURE SO
PROBABILITIES OF PRECIPITATION WERE LEFT AT 20-40%.
BROADER-SCALE RIDGING ALOFT IS POISED TO SET UP OVER THE CENTRAL
CONUS FOR MUCH OF NEXT WEEK, SO ABOVE-AVERAGE TEMPERATURES WITH
HIGHS IN THE 30S ARE FORECAST, WITH THE CPC 6-10 DAY OUTLOOK
ALSO HIGHLIGHTING THIS TIMEFRAME AS A HIGH (90-100%) CHANCE FOR
ABOVE-AVERAGE TEMPERATURES.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1146 PM CST WED DEC 18 2024
SATELLITE TONIGHT SHOWS INCREASING CLOUDS OUT AHEAD OF AN
APPROACHING CLIPPER SYSTEM. RADAR HIGHLIGHTS SNOW AND MVFR CEILINGS
WILL SPREADING IN FROM THE WEST. THIS WILL CONTINUE ON AN EASTWARD
TRAJECTORY THROUGH TOMORROW WITH SNOWY CONDITIONS PERSISTING THROUGH
THE DAY. THERE WILL BE SOME DECENT FORCING ASSOCIATED WITH THIS
SYSTEM ALLOWING FOR SOME ROBUST SNOWBANDS AT TIMES THAT WILL GREATLY
IMPACT VISIBILITIES. THE HEAVIEST SNOW IS EXPECTED THROUGH THE
MORNING HOURS WITH ACTIVITY BEGINNING TO WANE AS WE HEAD INTO THE
AFTERNOON AND EVENING.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 404 PM CST WED DEC 18 2024
A CLIPPER WILL MOVE IN LATER TONIGHT FROM NORTH DAKOTA INTO
NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN. SOUTHEAST WINDS WILL
CARRY GUSTS OF AROUND 20 KNOTS EARLY THURSDAY MORNING. A SMALL CRAFT
ADVISORY WILL BE PUT IN PLACE THURSDAY AFTERNOON FOR REGIONS ABOVE
SILVER BAY AND UP TO GRAND MARAIS. AS THE CLIPPER MOVES FURTHER
SOUTH EARLY ON FRIDAY, WINDS WILL SHIFT AND COME FROM THE NORTH WITH
GUSTS OF UP TO 27 KNOTS. A SMALL CRAFT ADVISORY WILL BE ISSUED FOR
ALL WESTERN LAKE SUPERIOR NEARSHORE WATERS THURSDAY NIGHT INTO
FRIDAY MORNING. WAVE HEIGHTS DURING THIS TIME MAY REACH UP TO 7 FEET
ALONG THE APOSTLE ISLANDS EARLY ON FRIDAY MORNING.
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 THURSDAY NIGHT FOR
MNZ010-018-019-021-025-026-035.
WINTER STORM WARNING UNTIL MIDNIGHT CST THURSDAY NIGHT FOR
MNZ020-033-034-036>038.
WI...WINTER WEATHER ADVISORY FROM 3 AM THURSDAY TO 6 AM CST FRIDAY
FOR WIZ001.
WINTER STORM WARNING FROM 3 AM THURSDAY TO 6 AM CST FRIDAY FOR
WIZ002.
WINTER WEATHER ADVISORY FROM 6 AM THURSDAY TO 9 AM CST FRIDAY
FOR WIZ003-004.
WINTER WEATHER ADVISORY FROM 3 AM THURSDAY TO 3 AM CST FRIDAY
FOR WIZ006>009.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THURSDAY TO 10 AM CST FRIDAY
FOR LSZ121-146>148-150.
SMALL CRAFT ADVISORY FROM 6 PM THURSDAY TO 8 AM CST FRIDAY FOR
LSZ140-143.
SMALL CRAFT ADVISORY FROM 3 PM THURSDAY TO 8 AM CST FRIDAY FOR
LSZ141-142.
SMALL CRAFT ADVISORY FROM 6 PM THURSDAY TO 6 AM CST FRIDAY FOR
LSZ144-145.
DISCUSSION...ROTHSTEIN
AVIATION...LB
MARINE...IGS
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