670
FXUS63 KGRR 281147
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
647 AM EST SAT FEB 28 2026
KEY MESSAGES
- SNOW ACCUMULATIONS LIKELY TONIGHT, HEAVIEST AXIS STILL UNCERTAIN
- IMPACTFUL WINTRY MIX LOOKING LIKELY TUESDAY
- WARMER LATE WEEK WITH RAIN CHANCES
DISCUSSION
ISSUED AT 245 AM EST SAT FEB 28 2026
- SNOW ACCUMULATIONS LIKELY TONIGHT, HEAVIEST AXIS STILL UNCERTAIN
BEING WITHIN 24 HOURS OF OUR NEXT SNOW EVENT, NORMALLY WE WOULD HAVE
THIS PINNED DOWN FAIRLY WELL. HOWEVER, THIS SYSTEM REMAINS A BIT
ELUSIVE REGARDS TO SPECIFIC SNOW AMOUNTS FOR EACH LOCATION AND
LOCATION OF THE HEAVIEST AXIS. QUITE A BIT OF UNCERTAINTY REMAINS
REGARDING THE SPECIFIC DETAILS AMONGST THE DETERMINISTIC AND
ENSEMBLE MEMBERS.
ENSEMBLE MEANS SUCH AS THE HREF ARE FAIRLY SMEARED OUT WITH THEIR
SNOW AMOUNTS. THIS IS DUE TO A WIDE RANGE OF SOLUTIONS SPREAD OUT,
WITH THEIR INDIVIDUAL MEMBERS SHOWING THE BETTER SNOW OCCURRING
ANYWHERE FROM NEAR I-94 TO NORTH OF I-96. AS HAS BEEN MENTIONED
REPEATEDLY OVER THE PAST FEW DAYS, THIS UNCERTAINTY IS TIED TO THE
MID LEVEL FGEN AND WHERE EXACTLY THE BEST FORCING JUST SOUTH OF THE
FGEN IS ABLE TO TRIGGER THE ATMOSPHERIC RESPONSE WITH THE STABILITY
PRESENT.
TAKING A STEP BACK TO LOOK AT THE BIGGER PICTURE, THERE IS A
SLIGHTLY ELEVATED CHANCE COMPARED TO THE REST OF THE AREA THAT THE
BEST AXIS OF ACCUMULATING SNOW WILL BE NEAR THE I-96 CORRIDOR.
EXTRAPOLATING THE TRACK OF THE FORECAST SNOW OUT TO OUR WEST WOULD
SUPPORT THIS, AS WOULD THE OVERALL MEAN OF ALL THE VARIOUS
SOLUTIONS. ONE THING TO NOTE TOO IS THAT THE UPPER LEVEL DIVERGENCE
WITH THE UPPER JET COUPLING AND THE RESULTING MID LEVEL FGEN WILL BE
WEAKENING AS IT MOVES OVERHEAD, COMPARED TO AREAS FURTHER WEST.
SO, A FORECAST OF 1 TO 2 INCHES FOR MOST OF THE AREA IS A
RESPONSIBLE WAY TO GO AT THIS POINT CONSIDERING THE CIRCUMSTANCES.
CHANCES ARE THIS IS OVERDONE A BIT FOR SOME AREAS ON THE NORTHERN
AND SOUTHERN PERIPHERIES, AND UNDERDONE FOR SOME OTHER AREAS WHERE
THE HEAVIEST AXIS ENDS UP. WE DO HAVE AREAS NEAR THE I-96 CORRIDOR
WITH A TAD HIGHER AMOUNTS (1-3 INCHES).
THE GOOD NEWS WITH THIS IS THAT GIVEN THE TIMING OF THE SNOW BEING
MAINLY EVENING INTO THE EARLY OVERNIGHT HOURS, IMPACTS WILL NOT BE
AS HIGH AS IF THIS CAME THROUGH DURING A WEEKDAY RUSH HOUR.
- IMPACTFUL WINTRY MIX LOOKING LIKELY TUESDAY
WE HAVE SEEN A NOTICEABLE ACCELERATION OF THE NEXT SYSTEM COMING
INTO THE AREA, GOING FROM TUESDAY NIGHT, TO NOW TUESDAY OVER THE
PAST COUPLE OF DAYS. THIS IS DUE TO THE SLOWER SOUTHERN STREAM
ENERGY COMING OUT OF THE DESERT SW, AND A NORTHERN STREAM SHORT WAVE
ABLE TO COME IN QUICKER NOT BEING PHASED. THE DEEP COLD AIR WILL
REMAIN WELL NORTH OF THE AREA WITH THE POLAR JET STAYING WELL OVER
CANADA. THE SHORT WAVE COMING THROUGH WILL BE ABLE TO ACT ON GULF
MOISTURE COMING NORTHWARD WITH THE SRN BRANCH OF THE JET. WE WILL
HAVE SHALLOW COLDER AIR NEAR THE SFC UNDERCUTTING THE WARMER AIR
ALOFT AND MOISTURE COMING IN.
THIS MEANS THAT WE HAVE A BETTER CHANCE FOR MORE OF THE FORECAST
AREA TO SEE A WINTRY MIX OF PRECIPITATION TYPES DURING THE DAYLIGHT
HOURS ON TUESDAY. THERE IS FAIRLY GOOD AGREEMENT WITH THE SYNOPTIC
MODELS AND ENSEMBLE MEMBERS SHOWING THAT THE SOUTHERN PORTION OF THE
FORECAST AREA NEAR I-94 WILL SEE MAINLY RAIN. THE UNCERTAINTY IS
WHERE TEMPS CAN BE ABOVE FREEZING VS. BELOW FREEZING THAT BRINGS
RAIN OR FREEZING RAIN. THIS AREA OF UNCERTAINTY IS REALLY CENTERED
ON THE I-96 CORRIDOR. STILL A FEW DAYS TO FIGURE THAT OUT, BUT IT IS
ENCOURAGING TO SEE THE DECENT AMOUNT OF AGREEMENT.
- WARMER LATE WEEK WITH RAIN CHANCES
WE SHOULD SEE A BREAK NOW ON WEDNESDAY, WITH WARMER AIR COMING IN ON
THE WAKE OF THE TUESDAY SYSTEM. THIS IS DUE TO RISING HEIGHTS IN THE
LONG WAVE PATTERN IN RESPONSE TO LOWERING HEIGHTS ACROSS THE WESTERN
U.S..
ANOTHER WAVE WILL MOVE IN FOR THURSDAY, BRINGING ANOTHER GOOD CHANCE
FOR PRECIPITATION. THE DIFFERENCE FOR THE THURSDAY SYSTEM IS THE
HIGHER HEIGHTS AND WARMER SFC TEMPS. WE STILL MAY HAVE A LITTLE
FREEZING RAIN UP NORTH THURSDAY WITH MARGINALLY COLD ENOUGH TEMPS
EARLY. OVERALL THOUGH THE WARMER TEMPS WILL SUPPORT MOSTLY RAIN FOR
MOST OF THE AREA.
THE THURSDAY SYSTEM WILL MARK THE CHANGE TAKING PLACE FROM THE MORE
ZONAL FLOW AND COOLER TEMPERATURES, TO MORE OF A FLOW FROM THE SW
BRINGING IN MORE WARM AIR AND RAIN.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 647 AM EST SAT FEB 28 2026
VFR CONDITIONS DOMINATE THIS MORNING AT ALL OF THE TERMINALS, IN
THE WAKE OF A WEAK COLD FRONT THAT HAS PASSED THROUGH THE AREA.
HIGH CLOUDS REMAIN OVER MUCH OF THE AREA THIS MORNING. CLOUDS WILL
LOWER AS THE NEXT AREA OF SNOW MOVES TOWARD THE AREA LATER THIS
AFTERNOON.
SOME UNCERTAINTY REMAINS AS THE BAND OF SNOW WILL BE SOMEWHAT
NARROW AS IT MOVES IN. THE VARIOUS SETS OF DATA CONTINUE TO
DIFFER ON THE TRACK, EVEN AS WE WARE WITHIN 24 HOURS. THE THOUGHT
IS THE I-96 CORRIDOR HAS A SLIGHT BIT BETTER OF A CHANCE OF SEEING
THE HEAVIER SNOW. WE HAVE GONE WITH LOWER CONDITIONS ALONG THE
I-96 CORRIDOR TERMINALS, AND LESS IMPACT FOR THE I-94 TERMINALS.
THE SNOW WILL MOVE OUT LATER THIS EVENING AND OVERNIGHT.
CONDITIONS WILL IMPROVE A BIT TO MVFR, BEFORE MORE IMPROVEMENT ON
SUNDAY MORNING.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...NJJ
AVIATION...NJJ
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