091  
FXUS63 KFGF 172057  
AFDFGF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND FORKS ND  
257 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.  
 

 
   
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 /18Z TAFS THROUGH 18Z WEDNESDAY/
 
 
ISSUED AT 100 PM CST TUE DEC 17 2024  
 
MVR AND IFR CEILINGS ARE FORECAST THROUGH MUCH OF THE AREA  
THROUGH AT LEAST 12Z WEDNESDAY. LIGHT SNOW IS ALSO FORECAST  
THROUGH AT LEAST 00Z THIS EVENING, WITH RECENT PIREPS INDICATING SOME  
ICING POTENTIAL OVER THE REGION.  
 
GETTING INTO WEDNESDAY MORNING, FORECAST GUIDANCE DOES OFFER  
SOME DIMINISHING IN CLOUD COVER, ALTHOUGH CONFIDENCE IS LOW ON  
THIS.  
 
ANOTHER SYSTEM WILL IMPACT THE REGION LATE WEDNESDAY THROUGH  
THURSDAY, INCLUDING ACCUMULATING SNOWFALL AND BLOWING SNOW.  
 

 
   
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.  
 

 
 

 
 
DISCUSSION...CJ  
AVIATION...CJ  
 
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