313
FXUS63 KGRR 170437
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1137 PM EST TUE DEC 16 2025
KEY MESSAGES
- THAW/FREEZE THIS WEEK WITH RAIN TO SNOW ON THURSDAY
DISCUSSION
ISSUED AT 327 PM EST TUE DEC 16 2025
- THAW/FREEZE WITH RAIN TO SNOW ON THURSDAY
AFTER A LONG STRETCH OF ARCTIC COLD, MILDER AIR ADVECTS INTO LOWER
MICHIGAN THE NEXT COUPLE DAYS CULMINATING IN RAIN ON THURSDAY AHEAD
OF AN EASTWARD SURGING COLD FRONT, FOLLOWED BY A CHANGE TO SNOW
AND SLIPPERY TRAVEL FOR FRIDAY.
FOR TONIGHT, WE WILL HAVE TO MONITOR AN AREA OF WARM AIR ADVECTION
SHOWERS COMING IN FROM THE WEST INTO NORTHERN LOWER MICHIGAN,
WHICH COULD BRING LIGHT FREEZING PRECIP, MOST LIKELY IN THE FORM
OF FREEZING DRIZZLE, ACROSS THE NORTHERN TIER OF THE FORECAST AREA
OVERNIGHT. FORECAST SOUNDINGS SHOW AN UNSATURATED DGZ BUT NOT
MUCH LIFT THROUGH THE LOW CLOUD LAYER, SO ANY PRECIP SHOULD BE
LIGHT ENOUGH THAT TRAVEL IMPACTS ARE NOT EXPECTED.
A SURFACE LOW WILL BE TRACKING NORTH OF LOWER MICHIGAN ON
THURSDAY WITH RAIN BREAKING OUT EARLY IN THE DAY AS THE WARM
CONVEYOR BELT FEEDS MOISTURE NORTHWARD. FORECAST SOUNDINGS SHOW
SOME ELEVATED INSTABILITY AND LOW-TOPPED CONVECTION IS POSSIBLE
ACROSS SE LOWER MICHIGAN BY AFTERNOON. CURRENT FORECAST TOTAL RAIN
ON THURSDAY IS AROUND .30 TO .40 OF AN INCH. WITH ABOVE FREEZING
TEMPS AND WINDS GUSTING OVER 20 MPH, WE EXPECT SNOWMELT AS WELL
BUT A QUICK FREEZE UP ON THURSDAY NIGHT SHOULD PREVENT MOST OF THE
LIQUID FROM REACHING THE RIVERS.
THERE COULD BE IMPACTS TO TRAVEL FOR THE FRIDAY MORNING COMMUTE AS
RESIDUAL WATER ON PAVEMENT FROM SNOWMELT AND RAIN FREEZES INTO
ICE. LAKE-ENHANCED SNOW SHOWERS EXPECTED TO ADD AN INCH OR TWO OF
POWDER ON TOP OF THE ICE, PROLONGING TRAVEL IMPACTS ON UNTREATED
SURFACES INTO THE EVENING COMMUTE.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1137 PM EST TUE DEC 16 2025
THE TERMINALS ARE ALL VFR TO START THIS FORECAST PERIOD, WITH JUST
HIGH CLOUDS CURRENTLY OVER THE AREA. A WEAK FRONT DROPPING DOWN
WILL BE BRINGING SOME LOWER CLOUDS OVER THE AREA. JUST HOW MUCH
COVERAGE WE SEE IN THE LOW CLOUDS IS SOMEWHAT UNCERTAIN WITH
DISAGREEMENT AMONGST THE DATA. GIVEN THE FRONT IS EXPECTED NOT TO
GO FAR, THERE IS A BETTER CHANCE THE LOWER CLOUDS WILL PERSIST,
ALTHOUGH THERE MAY BE BREAKS IN THE LOWER CLOUDS AT TIMES RIGHT ON
THROUGH TOMORROW AFTERNOON. KAZO AND KBTL MAY NOT SEE THE
CEILINGS HANG ON AS THE FRONT STARTS MOVING BACK TO THE NORTH AND
AWAY FROM THOSE TERMINALS.
WE TOOK THE LOW LEVEL WIND SHEAR OUT OF THE FORECAST FOR TONIGHT.
WE HAVE WIND GUSTS AT JUST ABOUT ALL OF THE TERMINALS, KEEPING THE
DIFFERENCE BETWEEN THE SFC AND 2K FT AGL LOW ENOUGH TO NO MENTION
IT AT THIS TIME. WE WILL SEE A STRONGER WIND CORE MOVE OVERHEAD AT
THE END OF THIS FORECAST PERIOD, AND SFC WINDS WILL REMAIN MORE
DECOUPLED THAN TONIGHT. WE HAVE ADDED LOW LEVEL WIND SHEAR TO THE
FORECAST AFTER 01-03Z THU.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST WEDNESDAY FOR LMZ844-845.
GALE WARNING UNTIL 4 AM EST WEDNESDAY FOR LMZ846>849.
DISCUSSION...OSTUNO
AVIATION...NJJ
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