828
FXUS63 KFGF 172329
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
529 PM CST TUE DEC 17 2024
KEY MESSAGES
- A CLIPPER SYSTEM WILL MOVE THROUGH THE REGION BRINGING WINTER
IMPACTS FROM ACCUMULATING AND BLOWING SNOW. EASTERN NORTH
DAKOTA INTO THE RED RIVER VALLEY HOLDS A 60% CHANCE OF
WARNING-TYPE IMPACTS RESULTING IN VERY DIFFICULT TRAVEL
CONDITIONS.
UPDATE
ISSUED AT 526 PM CST TUE DEC 17 2024
FLURRIES CONTINUE THIS EVENING ACROSS EASTERN NORTH DAKOTA AND
NORTHWEST MINNESOTA. IMPACTS WILL REMAIN FAIRLY LIGHT AS THERE
REALLY ISN'T A WHOLE LOT TO TALK ABOUT RIGHT NOW. A COLD FRONT
WILL SWEEP THROUGH OVERNIGHT TONIGHT, CLEARING SKIES FOR A BRIEF
PERIOD TOMORROW BEFORE THE NEXT SYSTEM ARRIVES.
DISCUSSION
ISSUED AT 213 PM CST TUE DEC 17 2024
..SYNOPSIS
CURRENT WATER VAPOR IMAGERY REVEALS ONE OR TWO LOW AMPLITUDE
SHORTWAVE TROUGH MOVING EAST THROUGH THE DAKOTAS INTO MINNESOTA,
AS WELL AS ANOTHER ONE DIGGING SOUTHEAST THROUGH MB INTO ON.
SUFFICIENT AMOUNT OF MOISTURE EXISTS OVER THE REGION AS IMPLIED
BY WIDESPREAD, HEAPING STRATUS UNDER AREAS OF CIRROSTRATUS. THIS
IS RESULTING IN AREAS OF LIGHT SNOW AND FLURRIES. AS THESE
SYNOPTIC FEATURES CONTINUE EAST/SOUTHEAST AND LOW LEVEL MOISTURE
LINGERS, LIGHT SNOW WILL REMAIN POSSIBLE. THAT IS UNTIL A COLD
FRONT MOVES THROUGH TONIGHT HELPING WHISK MOISTURE AWAY,
LOWERING THE CHANCE FOR LIGHT SNOW. BEHIND THE FRONT TONIGHT,
BREEZY NORTHWEST WINDS WILL LEAD TO DRIFTING SNOW IN OPEN
COUNTRY.
AFTER A GENERALLY QUIET, COOLER WEDNESDAY, A POTENT CLIPPER
SYSTEM QUICKLY MOVES THROUGH THE NORTHERN PLAINS OUT OF THE
CANADIAN HIGH PLAINS LATE WEDNESDAY THROUGH THURSDAY, AS
UNANIMOUSLY ADVERTISED BY ENSEMBLE GUIDANCE. THIS WILL BRING A
2-8 INCH SWATH OF SNOWFALL OVER PORTIONS OF ND INTO MN, AS WELL
AS GUSTY NORTH WINDS OVER 35 MPH, RESULTING IN WINTER IMPACTS.
MORE DETAILS ON POTENTIAL FOR WINTER IMPACTS LATE WEDNESDAY
THROUGH THURSDAY CAN BE FOUND BELOW.
BEHIND THE DEPARTING CLIPPER SYSTEM, NORTHWEST FLOW ALOFT
REMAINS IN PLACE POTENTIALLY TURNING QUASI-ZONAL WITH UPPER
RIDGING IN THE WEST GRADUALLY BREAKING DOWN BY EARLY NEXT WEEK.,
ONE OR MORE PROGRESSIVE EMBEDDED SHORTWAVE TROUGHS MOVES
THROUGH THE FLOW BRINGING PERIODIC CHANCES FOR LIGHT WINTRY
PRECIPITATION, ONE OF WHICH GENERALLY AGREED UPON IS AROUND
FRIDAY. AS OF NOW, MOST GUIDANCE KEEPS THESE WAVES PROGRESSIVE
AND ON THE WEAKER SIDE OF FORCING, KEEPING POTENTIAL FOR HIGH
IMPACTS VERY LOW (LESS THAN 10%), BUT CHANCE FOR ANY IMPACTS
STILL GREATER THAN 10%.
..WINTER IMPACTS LATE WEDNESDAY - THURSDAY
WHILE MOST ENSEMBLE GUIDANCE PAINTS THE GENERAL SYNOPTIC PICTURE OF
CLIPPER'S TRACK WITHIN NORTH DAKOTA INTO CENTRAL MINNESOTA,
SPECIFIC DETAILS ON TRACK AND STRENGTH OF THE CLIPPER STILL
DIFFER. THIS IS IMPORTANT AS THIS WILL INFLUENCE SNOWFALL
PLACEMENT AS WELL AS AREA OF GUSTY WINDS OVERSPREADING NEWLY
FELLED SNOWFALL LEADING TO BLOWING SNOW IMPACTS. SNOW WILL START
WEDNESDAY OVERNIGHT FROM EAST TO WEST INITIALLY AS A RESULT OF
STRONG LOW LEVEL WARM AIR ADVECTION, WITH TRANSIENT ENHANCEMENTS
FROM FRONTOGENESIS LEADING TO OVERALL LIGHT AND MODERATE
SNOWFALL, WITH BURSTS/BRIEF HEAVY SNOWFALL RATES. CLOSER TO THE
CENTER OF THE MID LEVEL WAVE, SYNOPTIC FORCING FROM VORTICITY
ADVECTION INCREASES, AS WELL AS SNOW GROWTH WITHIN THE DENDRITIC
GROWTH ZONE, GENERALLY AS WAA AND FGEN WANES, INCREASING SNOW
RATIOS AND MAINTAINING THE POTENTIAL FOR LOCALIZED AREAS OF
HEAVY SNOW RATES. ADDITIONALLY, SOME CONDITIONAL INSTABILITY
EXISTS IN THE UPPER LEVELS WHERE SNOW PRODUCTION WILL INITIALLY
START VIA SYNOPTIC FORCING, ALSO ADDING TO POTENTIAL FOR BURSTS
OF HEAVIER SNOW RATES.
A WIDE SWATH OF 2-5 INCHES CAN BE EXPECTED WITHIN EASTERN NORTH
DAKOTA INTO WEST-CENTRAL AND NORTHWEST MINNESOTA (EXCLUDING
LAKE OF THE WOODS AREA), WITH MORE LOCALIZED AREAS OF 5-8 INCHES
WITHIN THIS SWATH. LOCATION OF THESE LOCALLY HIGHER AMOUNTS
REMAINS UNKNOWN DUE TO MESOSCALE DETAILS YET TO BE RESOLVED AND
AGREED UPON FROM HIGH RESOLUTION GUIDANCE. WHILE CURRENT
GUIDANCE OFFERS RELATIVELY HIGHER PROBABILITIES OF 6 OR MORE
INCHES WITHIN NORTHEAST NORTH DAKOTA, THERE ARE STILL SOME
GUIDANCE OFFERING HIGHER AMOUNTS AS FAR SOUTH AS SOUTHEAST ND
INTO WEST-CENTRAL MN.
ADDITIONALLY, AS THE SURFACE LOW DEPARTS INTO MINNESOTA EARLY
THURSDAY, INCREASING PRESSURE GRADIENT WILL CONTRIBUTE TO
INCREASING NORTHERLY WINDS. BEST MIXING POTENTIAL IS FAVORED TO
BYPASS OUR AREA TO THE WEST AND SOUTH, HOWEVER JUST ENOUGH
MIXING POTENTIAL COUPLED WITH TIGHTENING PRESSURE GRADIENT WILL
ALLOW POTENTIAL FOR SUSTAINED WINDS 20-30 MPH, GUSTING OVER 35
MPH. BEST CHANCE FOR HIGHEST WINDS RESIDES WITHIN SOUTHEAST
NORTH DAKOTA AND THE SOUTHERN RED RIVER VALLEY ON THURSDAY.
SHOULD SUSTAINED WINDS GET NEAR 30 MPH AND A FRESH 2 OR MORE
INCHES OF SNOW HAS FALLEN AND/OR LIGHT SNOW CONTINUES TO FALL,
WHITEOUT CONDITIONS WILL ENSUE.
THE COMBINATION OF SEEING SNOW ACCUMULATION OVER 6 INCHES AS
WELL AS SIGNIFICANTLY REDUCED VISIBILITIES FROM HEAVY SNOWFALL
RATES AND BLOWING SNOW (POTENTIALLY WHITEOUT AT TIMES) IS
LEADING TO POTENTIAL FOR WARNING-TYPE IMPACTS RESULTANT FROM
VERY DIFFICULT TRAVEL CONDITIONS. THIS LEAD TO THE ISSUANCE OF
A WINTER STORM WATCH FOR EASTERN NORTH DAKOTA INTO THE RED RIVER
VALLEY WITH 60% CHANCE OF SEEING THESE HIGHER IMPACTS WITHIN
THIS AREA.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 526 PM CST TUE DEC 17 2024
MVFR TO VFR CONDITIONS WILL PREVAIL FOR THE FIRST SIX HOURS OF
THE TAF PERIOD, FOLLOWED BY IMPROVING CEILINGS AFTER 06Z TO VFR.
VFR CONDITIONS WILL LINGER THROUGH A MAJORITY OF THE DAY
TOMORROW BEFORE THEY FALL AGAIN BY THE END OF THE TAF PERIOD.
LIGHT SNOW MAY CONTINUE TO IMPACT TAF SITES WHILE UNDER MVFR TO
LOW END VFR CEILINGS, BUT IMPACTS TO VISIBILITY WILL BE MINIMAL
TO NONEXISTENT. WINDS WILL BRIEFLY INCREASE FROM A DIRECTION OF
300-330 AS THE FRONT SWEEPS THROUGH THIS EVENING, LINGERING
THERE THROUGH THE MORNING. EVENTUALLY, WINDS WILL BECOME LIGHT
AND VARIABLE FROM WEST TO EAST TOMORROW AFTERNOON.
FGF WATCHES/WARNINGS/ADVISORIES
ND...WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
AFTERNOON FOR NDZ006>008-014>016-024-026>030-038-039-049-
052>054.
MN...WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
AFTERNOON FOR MNZ001>003-027-029-030-040.
UPDATE...PERROUX
DISCUSSION...CJ
AVIATION...PERROUX
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