814
FXUS63 KGRR 180555
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
155 AM EDT WED MAR 18 2026
KEY MESSAGES
- LIGHT SNOW ACCUMULATIONS LIKELY WED
- RAIN CHANCES THU/FRI, POTENTIALLY SIGNIFICANT WARMUP SATURDAY
- RAIN TO SNOW SAT NIGHT/SUN WITH COOLER TEMPERATURES EARLY NEXT WEEK
DISCUSSION
ISSUED AT 324 PM EDT TUE MAR 17 2026
- LIGHT SNOW ACCUMULATIONS LIKELY WED
THE LAST VESTIGES OF THE MAJOR STORM SYSTEM THAT AFFECTED THE REGION
OVER THE WEEKEND ARE DIMINISHING OVER THE AREA THIS AFTERNOON AS THE
UPPER LOW PULLS AWAY. EVEN THOUGH SNOW SHOWERS ARE EXPANDING ACROSS
MOST OF THE AREA ON THE RADAR WITH A DIURNAL BOOST, THE INTENSITY OF
THE SNOW SHOWERS HAS NOTICEABLY TRENDED DOWN OVER THE LAST FEW
HOURS. THIS JIVES WELL WITH THE UPPER JET/SHEAR ZONE PUSHING EAST OF
THE AREA, AND THE UPPER FLOW BECOMING ANTI-CYCLONIC THIS AFTERNOON.
WE WILL SEE ONLY A BRIEF BREAK IN THE SNOW SHOWER ACTIVITY TONIGHT
AS A WEAK RIDGE MOVES THROUGH. THE NEXT SHORT WAVE CURRENTLY NEAR
MINNESOTA IS POISED TO MOVE AT THE AREA VERY LATE TONIGHT AND ON
WEDNESDAY. THIS SYSTEM LOOKS QUITE WEAK WITH LIMITED IMPACTS
EXPECTED. A MAJOR REASON FOR THIS IS THAT WE DO NOT SEE A DEEPLY
SATURATED COLUMN WITH THIS SYSTEM ABOUT THE TIME THE LOWER LEVELS
SATURATE SUFFICIENTLY TO ALLOW SNOW TO REACH THE GROUND, THE
MID/UPPER LEVEL MOISTURE IS ALREADY PEELING AWAY.
THIS SYSTEM IS EXPECTED TO PRODUCE LESS THAN AN INCH OF SNOW FOR
MOST OF THE AREA. AREAS ALONG THE LAKESHORE WITH A LOW LEVEL FLOW
FROM THE SW COULD BUMP THOSE TOTALS UP A BIT DUE TO SOME LAKE
ENHANCEMENT. FORECAST SOUNDINGS AND SYNOPTIC LEVEL VIEWS INDICATE
THAT INVERSION HEIGHTS ARE LOW, RESULTING FROM A LACK OF DEEP COLD
AIR WITH THIS SYSTEM. THIS WILL KEEP THE HIGHEST SNOW AMOUNTS FROM
BEING MUCH HIGHER THAN 2-3 INCHES.
ONE SMALL CONCERN WITH THIS SYSTEM IS WE COULD SEE A BRIEF PERIOD OF
FREEZING DRIZZLE ON THE BACKSIDE OF THE SYSTEM. THIS RESULTS FROM
LOSING THE MID AND UPPER LEVEL MOISTURE, AND THE DGZ BECOMING
UNSATURATED. THIS WOULD BE BRIEF, IF IT HAPPENS AT ALL. THAT SAID,
IT DOESN'T TAKE MUCH FREEZING DRIZZLE TO CAUSE SOME MINOR IMPACTS.
- RAIN CHANCES THU/FRI, POTENTIALLY SIGNIFICANT WARMUP SATURDAY
YET ANOTHER WEAK SYSTEM IN THE FLOW WILL ARRIVE AS EARLY AS PRE-DAWN
THURSDAY MORNING, AND MORE LIKELY DURING THE DAY. THIS SYSTEM ONCE
AGAIN WILL NOT HAVE A SIGNIFICANT AMOUNT OF MOISTURE ASSOCIATED WITH
IT AS THE LOW LEVEL FLOW WILL BE COMING FROM THE SOUTHERN PLAINS.
A DIFFERENCE WITH THIS SYSTEM FROM WED'S SYSTEM IS UPPER HEIGHTS
WILL BE A BIT HIGHER, THUS IMPLYING A LITTLE WARMER. THE COLUMN
GENERALLY LOOKS LIKE ONE WHERE MAINLY RAIN IS EXPECTED FOR MOST OF
OUR FORECAST AREA. THE EXCEPTIONS TO THIS WOULD BE ACROSS THE HIGHER
TERRAIN OF CENTRAL LOWER MICHIGAN WHERE SOME OF IT MAY BE SNOW
EARLY. IN ADDITION, IF THE SYSTEM COMES IN EARLY ENOUGH BEFORE
SUNRISE, SFC TEMPS MAY BE AROUND FREEZING, ALLOWING FOR A LITTLE BIT
OF FREEZING RAIN BEING POSSIBLE. TEMPERATURES ARE EXPECTED TO WARM
ABOVE FREEZING BY LATE THURSDAY MORNING.
ANOTHER SYSTEM IN THE FLOW COULD CLIP THE AREA ON FRIDAY. THIS
SYSTEM WILL BE FURTHER NORTH AS UPPER HEIGHTS WILL CONTINUE TO RISE
A BIT. MUCH OF THE AREA WILL LIKELY STAY DRY, WITH THE NORTHERN
PORTION OF THE FORECAST AREA SEEING THE BEST CHANCE OF SOME LIGHT
RAIN.
THE FRIDAY SYSTEM BEING FAR ENOUGH NORTH WILL ALLOW THE LOW LEVEL
FLOW FROM THE SW TO BECOME ESTABLISHED OVER THE AREA. THIS WILL BE
ADVECTING WARMER AIR UP AND OVER THE AREA. THIS FLOW WILL INCREASE
FRIDAY NIGHT INTO SATURDAY. WE WILL BE LOOKING AT SOME POTENTIALLY
WARM WEATHER, DEPENDING ON THE TIMING OF A FRONT PASSING THROUGH THE
AREA SOMETIME FROM EARLY SATURDAY THROUGH LATE SATURDAY. THE LATER
THIS FRONT MOVES THROUGH, THE BETTER THE CHANCE WE SEE WARMER
TEMPERATURES ON SATURDAY. THE TIMING IS UNCERTAIN AT THIS TIME, WITH
TEMPS ON SATURDAY BEING AS LOW AS THE UPPER 40S AND 50S, TO
POTENTIALLY IN THE 60S TO NEAR 70F.
- RAIN TO SNOW SAT NIGHT/SUN WITH COOLER TEMPERATURES EARLY NEXT WEEK
WHATEVER THE TIMING OF THE FRONT IS ON SATURDAY, IT WILL BECOME
ACTIVE SATURDAY NIGHT INTO SUNDAY WITH PRECIPITATION. IT IS LIKELY
TO BE WARM ENOUGH INITIALLY TO BE RAIN, BUT WILL TRANSITION OVER THE
SNOW AS COLDER AIR PUSHES IN THROUGH SUNDAY. STILL A LOT OF DETAILS
TO BE WORKED OUT WITH THIS OVER THE NEXT FEW DAYS.
WE WILL THEN SEE A FAIRLY STRONG CANADIAN SFC RIDGE MOVE OVER THE
AREA SUNDAY NIGHT AND LINGER THROUGH TUESDAY. THIS WILL BRING DRY
AND COOL CONDITIONS TO THE AREA.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 155 AM EDT WED MAR 18 2026
MADE MOSTLY MINOR TIMING CHANGES REGARDING THE ONSET OF SNOW FOR THIS
TAF PACKAGE. THE REAL QUESTION IS WHETHER (OR FOR HOW LONG) WE
ACHIEVE IFR VISIBILITY RESTRICTIONS. UPSTREAM OBSERVATIONS IN WI
DO INDICATE SOME VISIBILITIES IN THE 1-3SM RANGE, AND WE MIGHT
GET A BIT OF A BOOST FROM LAKE MI. SO, THERE IS SIGNIFICANT
POTENTIAL FOR THE JUST-ISSUED TAF PACKAGE TO REQUIRE MORE
PESSIMISTIC UPDATES IN TERMS OF IFR VISIBILITY RESTRICTIONS.
CEILINGS WILL BE A BIT TRICKY AS WELL. UPSTREAM OBSERVATIONS
INDICATE CLOUD BASES ABOVE 2000 FT AGL EVEN IN SNOW, BUT TEMPORARY
LIFR CEILING RESTRICTIONS CAN'T BE COMPLETELY RULED OUT THIS SIDE
OF LAKE MI.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM EARLY THIS MORNING TO 11 PM EDT
THIS EVENING FOR LMZ844>849.
DISCUSSION...NJJ
AVIATION...TJT
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