377
FXUS63 KGRR 312032
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
332 PM EST FRI JAN 31 2025
KEY MESSAGES
- ONGOING RAIN EVENT WILL MIX WITH SOME SNOW BEFORE ENDING
- CLIPPER SYSTEM ON SUNDAY TO BRING A MIX OF RAIN AND SNOW
- MONITORING MODEL TRENDS FOR MID NEXT WEEK SYSTEM
DISCUSSION
ISSUED AT 332 PM EST FRI JAN 31 2025
- ONGOING RAIN EVENT WILL MIX WITH SOME SNOW BEFORE ENDING
THE ONGOING RAIN EVENT HAS OVERPERFORMED A BIT IN OUR SOUTHERN
FORECAST AREA, NAMELY ALONG THE I-94 CORRIDOR. RAINFALL AMOUNTS
HAVE PUSHED TOWARDS 1.25 INCHES IN SPOTS. LOOKING AT HYDROGRAPHS
ACROSS THE AREA THERE ARE WITHIN BANK RISES THAT ARE TAKING PLACE.
LOCALIZED PONDING OF WATER IS CERTAINLY POSSIBLE AND SOME SMALLER
STREAMS MAY CLIMB OUT OF THEIR BANKS FOR A TIME THIS EVENING. WE
THEREFORE HAVE ISSUED A FLOOD ADVISORY FOR ALLEGAN, VAN BUREN AND
KALAMAZOO COUNTIES THIS EVENING.
THE UPPER WAVE AND SURFACE LOW MOVE OFF TO THE EAST THIS EVENING
WHICH WILL ALLOW THE PRECIPITATION TO COME TO AN END. THE
PRECIPITATION IS BEING FOCUSED BY AN EAST-WEST STATIONARY BOUNDARY
THAT WILL SAG SOUTHWARD THIS EVENING. TEMPERATURES AT THIS TIME
ARE IN THE MIDDLE TO UPPER 30S ACROSS SOUTHERN LOWER MICHIGAN. AS
TEMPERATURES COOL A BIT THIS EVENING A LIGHT MIXTURE OF
PRECIPITATION IS EXPECTED. WE HAVE HAD REPORTS OF SOME SLEET
BRIEFLY MIXING IN AND WE EXPECT SOME SNOW AS WELL. ANY WINTRY
ACCUMULATIONS OF PRECIPITATION SHOULD AMOUNT TO LITTLE TO NONE AT
MOST LOCATIONS.
- CLIPPER SYSTEM ON SUNDAY TO BRING A MIX OF RAIN AND SNOW
A CLIPPER SYSTEM MOVING THROUGH THE ZONAL FLOW SATURDAY NIGHT
INTO SUNDAY WILL BRING A MIX OF RAIN AND SNOW TO SOUTHWEST LOWER
MICHIGAN. THIS HAS BEEN A FAIRLY CONSISTENT SYSTEM IN THE MODELS
WITH 1-2 OR 1-3 INCHES POSSIBLE NEAR AND NORTH OF I-96. TO THE
SOUTH, A MIX WITH RAIN CAN BE EXPECTED. WARMING TEMPERATURES AT
THE SURFACE SHOULD KEEP MUCH IN THE WAY OF WINTRY IMPACTS AT BAY.
- MONITORING MODEL TRENDS FOR MID NEXT WEEK SYSTEM
THE MID WEEK SYSTEM STILL HAS SOME MODEL DISPARITY TO IT. THE
OPERATIONAL ECWMF IS WARM WITH A TRACK OF THE LOW TO THE WEST. THE
ECMWF TRACK IS OVER THE TOP OF OUR AREA OR JUST WEST WITH A BIT OF
A DEEP LOW AROUND 998MB. THE GFS IS WEAKER WITH A FLATTER TRACK TO
OUR SOUTH. IN EITHER MODEL HOWEVER A SURGE OF WARMER AIR MOVES
INTO THE GREAT LAKES WITH +5C AT 850MB AT 06Z THURS NEAR AZO VIA
THE GFS, WHILE THE ECWMF HAS +10C. EITHER WAY THIS IS A WARM
SYSTEM THAT WOULD RESULT IN RAIN. NEITHER MODEL HAS MUCH IN THE
WAY ON SNOW ON THE LEADING EDGE AS THE WARM AIR NOSES IN.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1244 PM EST FRI JAN 31 2025
WE ARE STARTING OUT THIS FORECAST PERIOD WITH IFR-LIFR CONDITIONS
WITH RAIN AND LOW CLOUDS AT ALL TERMINALS EXCEPT KMKG AND KGRR,
WHERE THEY ARE BOUNCING BACK AND FORTH FROM MVFR TO VFR. THE RAIN
SHOULD SLIP SOUTH OF KGRR BY 20Z. WE EXPECT THAT MVFR CEILINGS
WILL HOLD IN OVER KGRR MORE THAN NOT INTO THE EVENING HOURS BEFORE
THE GET INTO THE SOLID VFR CONDITIONS. ALL SITES WILL HAVE WIND
GUSTS OF 20-25 KNOTS UNTIL SUNSET THIS EVENING.
THE SOUTHERN SITES WILL SEE THE RAIN AND LIFR CONDITIONS LAST MOST
OF THE AFTERNOON. THEY WILL THEN GRADUALLY IMPROVE FROM NORTH TO
SOUTH LATER THIS EVENING AND OVERNIGHT AS DRIER AIR MOVES IN. ALL
SITES SHOULD GO VFR BY DAYBREAK ON SATURDAY, AND STAY VFR UNTIL
AFTER THIS FORECAST PERIOD.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST SATURDAY FOR LMZ844-845-848-
849.
DISCUSSION...DUKE
AVIATION...NJJ
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