526
FXUS63 KDLH 212047
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
247 PM CST SAT DEC 21 2024
KEY MESSAGES
- NORTH SHORE LAKE EFFECT SNOW EXPECTED TO CONTINUE THROUGH THIS
EVENING WITH LIGHT ACCUMULATIONS UP TO A COUPLE INCHES.
- A QUICK MOVING SYSTEM BRINGS ANOTHER CHANCE FOR SNOW LATE SUNDAY
INTO MONDAY MORNING. LIGHT ACCUMULATIONS EXPECTED WITH LOCALIZED
HIGHER AMOUNTS POSSIBLE.
- WARMING TREND THROUGH THE WEEK, WITH A CHANCE FOR A SYSTEM TO
BRING MIXED PRECIPITATION TOWARDS THE END.
DISCUSSION
ISSUED AT 237 PM CST SAT DEC 21 2024
THROUGH THE WEEKEND: A WEAK IMPULSE CONTINUES TO PRODUCE RADAR
RETURNS OVER NORTH-CENTRAL MN MOVING EAST EARLY THIS AFTERNOON, BUT
THANKS TO DRY AIR NEAR THE SURFACE, LITTLE TO NONE OF THIS HAS
ACTUALLY MADE IT TO THE GROUND. A LAKE-INDUCED MESO-LOW MOVED UP THE
NORTH SHORE TODAY, BUT HAS STEADILY LOST ITS STRUCTURE THIS
AFTERNOON, BECOMING MORE PURE LAKE EFFECT SNOW AS IT PROPAGATES
ACROSS PORTIONS OF COASTAL LAKE AND COOK COUNTY. AS THE SYNOPTIC
FEATURE PUSHES EAST, LAKE EFFECT MOISTURE SHOULD ALLOW FOR A
BLOSSOMING OF BETTER COVERAGE LAKE EFFECT SNOW ALONG THE NORTH SHORE
OVERNIGHT. HALF INCH UP TO NEAR 3 INCHES OF ACCUMULATIONS COULD BE
POSSIBLE, ESPECIALLY ALONG THE HIGHER TERRAIN IN COOK COUNTY.
SUNDAY-MONDAY SYSTEM: A STOUT LITTLE UPPER LEVEL SHORTWAVE IS
PROGGED TO MOVE OVER MINNESOTA AND WISCONSIN FAIRLY ZONALLY LATE
SUNDAY INTO MONDAY MORNING, BRINGING SOME LIGHT SNOW ACCUMULATIONS.
DETERMINISTIC MODEL DATA POINTS TO THIS SYSTEM CHECKING A LOT OF
BOXES FOR SOME ENHANCED BANDED SNOWFALL, WITH A GOOD HEIGHT
FALL/RISE COUPLET, SUFFICIENT DENDRITIC GROWTH ZONE MOISTURE AND
LIFT, AND SOME WEAK NEAR-SURFACE FRONTOGENESIS. MODELS CONTINUE TO
PICK UP ON THIS ZIPPY LOCALIZED HEAVY BAND HAVING THE POTENTIAL TO
OVERPRODUCE AND GIVE A SMALL AREA 2-4" OF SNOW. HOWEVER, AS A
TESTIMONIAL TO THE REMAINING UNCERTAINTY FOR THIS SYSTEM, MODEL-TO-
MODEL AND RUN-TO-RUN CONSISTENCY CONTINUES TO BE AN ISSUE. DEPENDING
ON YOUR DESIRED MODEL RUN OR ENSEMBLE MEMBER, THIS NARROW BAND COULD
BEGIN SET UP ANYWHERE FROM JUST NORTH OF THE TWIN PORTS TO
ROCHESTER. LATEST PROBABILITIES PUT THE GREATEST CHANCE FOR 1" OR
MORE SOMEWHERE IN THE NORTHWEST TO WEST-CENTRAL WISCONSIN AREA, BUT
WE'VE KEPT POPS FAIRLY BROAD AND NOT TOO HIGH DUE TO LINGERING LOW
CONFIDENCE. TWO OTHER CONSIDERATIONS FOR THIS SYSTEM: 1) WITH
NORTHEAST WINDS OVER LAKE SUPERIOR, SOME LAKE ENHANCEMENT COULD BE
POSSIBLE FOR COASTAL AREAS AND 2) MODEL SOUNDINGS SUGGEST THERE MAY
BE AREAS OF INSUFFICIENT DGZ MOISTURE, WHICH COULD LEAD TO SOME
PATCHY FREEZING DRIZZLE AT TIMES.
NEXT WEEK: MONDAY'S SYSTEM SPINS OUT AS QUICKLY AS IT ARRIVES,
LEAVING US WITH BUILDING HIGH PRESSURE AND FAIRLY QUIET WEATHER
THROUGH MIDWEEK. THIS WILL LEAD TO STEADILY WARMING TEMPERATURES AND
PROBABLY A FAIR AMOUNT OF CLOUDINESS IN A WAA REGIME. WARMING
CONTINUES INTO THE END OF THE WEEK, WITH WIDESPREAD HIGH TEMPERATURES
RISING OVER FREEZING BY THE 25TH OR 26TH. IF YOU'RE A SNOW
ENTHUSIAST, YOU MAY WANT TO LOOK AWAY BEFORE READING THIS NEXT PART.
THERE CONTINUES TO BE GROWING ENSEMBLE AGREEMENT FOR ONE OR MORE
SYSTEMS TO TRAVERSE THE UPPER MIDWEST LATE NEXT WEEK INTO THE
WEEKEND, WHICH BASED ON TEMPERATURES WOULD LIKELY BE A MESSY MIXED
PRECIPITATION TO ALL RAIN EVENT. TOO SOON TO EXACTLY PINPOINT THIS
OR TALK ABOUT POSSIBLE RAINFALL AMOUNTS. LATEST 2-3 WEEK GUIDANCE
SUGGESTS THAT HOPEFULLY INTO THE NEW YEAR WE'LL BE ABLE TO START
BRINGING OUR TEMPERATURES BACK TO MORE WINTER-LIKE LEVELS AND SEE
PREDOMINANT SNOW RETURN.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1132 AM CST SAT DEC 21 2024
MOSTLY VFR CONDITIONS THIS AFTERNOON ACROSS THE REGION. CHANCES FOR
WIDESPREAD SNOW SHOWERS IN NORTH-CENTRAL MINNESOTA HAVE DECREASED AS
DRY AIR HAS EATEN AWAY AT MOST OF IT. LOWER CEILINGS ARE EXPECTED TO
MOVE IN OVERNIGHT AND INTO SUNDAY MORNING. MVFR TO IFR CEILINGS ARE
EXPECTED AT MOST TERMINALS. SOUTHERLY WINDS SHOULD PICK UP A LITTLE
THROUGH SUNDAY MORNING, WITH SOME 15 TO 20 KNOTS GUSTS AT HYR.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 237 PM CST SAT DEC 21 2024
WINDS BECOME SOUTHERLY TODAY, INCREASING IN STRENGTH INTO SUNDAY
MORNING WITH A TIGHTENING PRESSURE GRADIENT. WIND GUSTS OF 20 TO 25
KNOTS ARE POSSIBLE EARLY THROUGH MID MORNING SUNDAY, WITH INCREASING
WAVE HEIGHTS OF 3 TO 6 FEET ALONG PORTIONS OF THE NORTH SHORE. A
SMALL CRAFT ADVISORY HAS BEEN ISSUED. THROUGH THE DAY AND EVENING
SUNDAY, WINDS SHOULD WEAKEN, EVENTUALLY BECOMING NORTHERLY INTO
MONDAY AROUND 10 TO 15 KNOTS.
FOR THE OPEN WATER DISCUSSION, REFER TO THE NWS MARQUETTE AREA
FORECAST DISCUSSION AT WEATHER.GOV/MQT.
DLH WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM CST SUNDAY FOR LSZ140-
141.
SMALL CRAFT ADVISORY FROM 4 AM TO 10 AM CST SUNDAY FOR LSZ147-
148-150.
DISCUSSION...LEVENS
AVIATION...LEVENS
MARINE...LEVENS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page