123
FXUS63 KDLH 202349
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
549 PM CST FRI DEC 20 2024
KEY MESSAGES
- CHILLY TEMPS TONIGHT WITH LOWS FALLING TO NEAR ZERO TO TEENS
BELOW ZERO, COLDEST IN NORTHEAST MINNESOTA.
- A CLIPPER MAY BRING A FEW INCHES OF SNOW SUNDAY NIGHT INTO
EARLY MONDAY MORNING. THE LOCATION OF THE MOST IMPACTFUL SNOW
IS UNCERTAIN AND WILL BE RATHER NARROW.
- GENERALLY QUIET AND MILD WEATHER FOR CHRISTMAS EVE AND
CHRISTMAS DAY.
DISCUSSION
ISSUED AT 549 PM CST FRI DEC 20 2024
A BROAD AREA OF SURFACE HIGH PRESSURE WILL DRIFT EASTWARD
OVERNIGHT. LIGHT WINDS AND CLEAR SKIES WILL PROVIDE EFFICIENT
RADIATIONAL COOLING ALLOWING TEMPERATURES TO DROP TO NEAR ZERO IN
NORTHWEST WISCONSIN AND THE MIDDLE TO LOW TEENS BELOW ZERO
NORTH OF THE IRON RANGE AND IN THE BOUNDARY WATERS.
THE SURFACE HIGH PRESSURE WILL DEPART TO THE EAST ON SATURDAY
WITH SOUTHERLY RETURN FLOW TO DEVELOP. A ZONE OF ISENTROPIC
ASCENT AND FRONTOGENESIS IN THE 850-650 MB LAYER MAY BE
SUFFICIENT FOR A FEW LIGHT SNOW SHOWERS MOVING INTO NORTH-CENTRAL
AND CENTRAL MINNESOTA SATURDAY MORNING. THERE ARE QUESTIONS
WHETHER ANY SNOWFLAKES WILL SURVIVE THE TRIP TO TO THE GROUND
WITH A RELATIVELY DEEP SUB-CLOUD DRY AIR LAYER. A FEW LIGHT SNOW
SHOWERS MAY DEVELOP ALONG THE NORTH SHORE DUE TO SURFACE
CONVERGENCE, LAKE-EFFECT PROCESSES, AND OROGRAPHIC ASCENT FROM
LATE MORNING TO THROUGH THE AFTERNOON. IN BOTH CASES ANY SNOW
ACCUMULATION SHOULD BE NEGLIGIBLE. HIGH TEMPERATURES WILL RECOVER
TO THE MIDDLE TO UPPER TEENS.
NOT AS COOL SATURDAY NIGHT AS WARM AIR ADVECTION PERSISTS. A
COMPACT SHORTWAVE TROUGH AND A LOBE OF VORTICITY WILL RIDE
SOUTHEASTWARD THROUGH THE UPPER-LEVEL FLOW. THE PASSAGE OF THAT
TROUGH WILL BE LARGELY UNEVENTFUL. HIGHS ON SUNDAY TREND WARMER
WITH READINGS IN THE MIDDLE 20S.
ANOTHER COMPACT TROUGH WILL PROPAGATE THROUGH THE REGION SUNDAY
NIGHT AND MONDAY. THE DETERMINISTIC AND ENSEMBLE FORECASTS
FEATURE A WIDE RANGE OF SOLUTIONS FOR THAT SYSTEM. NEARLY ALL
PRODUCE PRECIPITATION, BUT THE LOCATION VARIES FROM NORTHWEST
ONTARIO TO SOUTHERN MINNESOTA INTO SOUTHERN WISCONSIN. OVERALL A
LOW CONFIDENCE FORECAST FOR THAT SYSTEM. IT WILL BE RELATIVELY
MOISTURE STARVED WITH A SMALL AREA OF LIGHT SNOW EXPECTED. WHERE
THE HEAVIEST SNOW FALLS, UP TO A FEW INCHES OF ACCUMULATION ARE
POSSIBLE. WHEREVER THAT SNOW FALLS MAY SEE IMPACTS TO THE MONDAY
MORNING COMMUTE.
TEMPERATURES CONTINUE TO TREND WARMER THROUGH THE WEEK WITH HIGHS
ON BOXING DAY IN THE MIDDLE TO UPPER 30S. TOWARD THE END OF
CHRISTMAS WEEK, ANOTHER TROUGH WILL BRING A POTENTIAL FOR A FEW
ROUNDS OF WINTRY MIXED PRECIPITATION IN THE FORM OF RAIN, SNOW,
AND POSSIBLY FREEZING RAIN. IT'S FAR TOO EARLY TO TALK ABOUT
SPECIFIC TIMING OR AMOUNTS AND THERE IS CONSIDERABLE SPREAD IN
THE FORECAST GUIDANCE AS IS EXPECTED AT 7 TO 9 DAYS FROM THE
CURRENT TIME.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 549 PM CST FRI DEC 20 2024
VFR CONDITIONS COVERED THE NORTHLAND THIS EVENING WITH HIGH
PRESSURE MOVING THROUGH THE REGION. WINDS WILL BE LIGHT TONIGHT
AND BECOME SOUTHERLY SATURDAY FROM 5 TO 10 KNOTS WITH A FEW
HIGHER GUSTS.
THE LIGHT WINDS TONIGHT MAY ALLOW FOR SOME FOG TO FORM.
CONFIDENCE IS NOT VERY HIGH BUT WE DID KEEP SOME GOING AT KHIB
AND KINL. HREF/SREF PROBABILITIES FOR A VISIBILITY OF 2SM OR
LOWER IS 15 TO 30% BUT GIVEN THE LIGHT WINDS AND CLEAR SKIES,
THINK THEY ARE HIGHER THAN. SOME OF THE GUIDANCE IS ALSO
FORECASTING LOW CEILINGS TO DEVELOP BUT GIVEN THE DRY AIRMASS,
WE THINK THE CHANCES FOR THAT ARE TOO LOW TO INCLUDE.
A WEAK SHORTWAVE AND WARM AIR ADVECTION WILL LEAD TO MORE CLOUDS
SATURDAY AND PERHAPS SOME LIGHT SNOW. WE ADDED CHANCES FOR
WESTERN AND NORTHERN PORTIONS OF THE NORTHLAND, 20-30%. THERE
MAY BE A SATURATION ISSUE WHICH COULD LEAD TO AN EVEN LOWER
CHANCE FOR SOME PATCHY FREEZING DRIZZLE. LAKE EFFECT SNOW
SHOWERS WILL ALSO BE POSSIBLE SATURDAY INTO SUNDAY MORNING ALONG
THE NORTH SHORE, ESPECIALLY TOWARD GRAND MARAIS TO GRAND
PORTAGE.
MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
ISSUED AT 549 PM CST FRI DEC 20 2024
NORTHERLY WINDS EARLY THIS EVENING FROM 10 TO 20 KNOTS WILL
DECREASE TO 15 KNOTS OR LESS OVERNIGHT AS HIGH PRESSURE SLIDES
THROUGH THE AREA. THE WIND WILL REMAIN AT OR LOWER THAN 15 KNOTS
SATURDAY WITH MOST AREAS SEEING SOUTHERLY WINDS DEVELOP. THE
SOUTHERLY WINDS WILL INCREASE A BIT SATURDAY NIGHT BUT SHOULD
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS FOR MOST AREAS INTO
SUNDAY. HOWEVER, TACONITE HARBOR TO GRAND PORTAGE MAY SEE WINDS
AND WAVES STRONG ENOUGH TO REACH ADVISORY THRESHOLDS AND SMALL
CRAFT ADVISORIES WILL BE POSSIBLE THERE SATURDAY NIGHT INTO
SUNDAY.
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...NONE.
DISCUSSION...HUYCK
AVIATION...MELDE
MARINE...MELDE
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