741
FXUS63 KGRR 032030
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
330 PM EST MON FEB 3 2025
KEY MESSAGES
- FREEZING RAIN LIKELY WEDNESDAY NIGHT
- WINDY THURSDAY
- LIGHT SNOW OR A MIX LIKELY SATURDAY
DISCUSSION
ISSUED AT 330 PM EST MON FEB 3 2025
- FREEZING RAIN LIKELY WEDNESDAY NIGHT
GUIDANCE IS FINALLY CONVERGING ON A SOLUTION FOR THE MIDWEEK MIXED
PRECIP EVENT. THE BOTTOM LINE IS THAT WE EXPECT A PERIOD OF
FREEZING RAIN WEDNESDAY NIGHT BUT NOT A SIGNIFICANT AMOUNT.
THE ECE 50TH PERCENTILE QPF HAS BACKED DOWN IN SRN LWR MI AND IS
COMING MORE IN LINE WITH THE GEFS WHICH HAS CONSISTENTLY KEPT THE
HEAVIER CONVECTIVE SOUTH OF MI THROUGH THE OHIO VALLEY REGION.
CURRENT EXPECTATION IS FOR QPF AMOUNTS RANGING FROM AROUND ONE
TENTH TO ONE THIRD OF AN INCH IN THE GRR CWFA WITH THE HIGHEST
AMOUNTS NEAR/SOUTH OF I-94.
NBM PROBABILISTIC P-TYPE DATASETS AND FCST SOUNDINGS IMPLY THAT
FREEZING RAIN WILL BE THE DOMINANT P-TYPE NEAR AND SOUTH OF I-96
WEDNESDAY NIGHT (LIKELY STARTING AS A BIT OF LIGHT SNOW LATE
WEDNESDAY). FRAM TECHNIQUE YIELDS ICE ACCRETION AMOUNTS OF A
TENTH TO TWO TENTHS OF AN INCH ACROSS THIS AREA BY 12Z THURSDAY
BEFORE THE DRY SLOT SWEEPS IN AND ABRUPTLY ENDS THE PRECIP
THREAT.
FOR THE AREA NORTH OF I-96, LIGHT SNOW MIXED WITH SOME FREEZING
RAIN IS THE MOST LIKELY SCENARIO AT THIS TIME, WITH SNOW ACCUMS UP
TO 1" AND LIGHT ICE ACCRETION OF GENERALLY LESS THAN ONE TENTH OF
AN INCH.
THE THURSDAY MORNING COMMUTE COULD BE A SLOW/CHALLENGING ONE DUE
TO SLICK CONDITIONS CREATED BY THE ICE ALTHOUGH IT MAY BE WARMING
ABOVE FREEZING ALREADY ALONG THE I-94 CORRIDOR AROUND THAT TIME.
A WINTER WEATHER ADVISORY FOR TRAVEL IMPACTS MAY BE NEEDED
WEDNESDAY NIGHT INTO EARLY THURSDAY.
- WINDY THURSDAY
THERE IS ALSO BETTER AGREEMENT IN THE WIND GUST GUIDANCE FOR
THURSDAY AND THE TREND FOR HIGHER VALUES IS INCREASING. THE
PROBABILITY FOR GUSTS OVER 40 MPH IN THE AFTERNOON EXCEEDS 70
PERCENT AT MOST LOCATIONS AND IF ANY SUNSHINE/DEEPER MIXING
DEVELOPS IN THE DRY SLOT WE MAY NEED A WIND ADVISORY. THE GOOD
THING IS THAT TEMPS ARE EXPECTED TO RISE INTO THE MID TO UPPER 30S
ON THURSDAY WHICH SHOULD MELT OFF THE MAJORITY OF ANY ICE FROM
LIMBS/POWER LINES BEFORE THE STRONGEST GUSTS DEVELOP. GALES ARE
POSSIBLE ON LAKE MICHIGAN.
- LIGHT SNOW OR A MIX LIKELY SATURDAY
ANOTHER SYSTEM SIMILAR TO THE MIDWEEK ONE SCOOTS THROUGH THE AREA
ON SATURDAY IN THE FAST ZONAL FLOW ALOFT AND CURRENTLY SNOW LOOKS
TO BE THE PREDOMINANT P-TYPE. HOWEVER 20-30 PCT FREEZING RAIN
PROBABILITIES DO SNEAK INTO THE AREA SOUTH OF I-96. HIGHEST QPF
AMOUNTS ARE SHOWN AGAIN TO BE SOUTH OF MI OVER THE OHIO VALLEY BUT
THERE SHOULD BE ENOUGH HERE IN MI TO PRODUCE SOME LIGHT
ACCUMULATIONS OF SNOW AND/OR ICE WHICH COULD IMPACT TRAVEL.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1247 PM EST MON FEB 3 2025
FOR JXN/AZO/BTL A BRIEF SURGE OF DRIER AIR WILL LEAD TO A VFR
CIGS WITH A MIX OF VFR AND MVFR VISBYS AS THE FOG BECOMES PATCHY.
FURTHER NORTH, LAN, GRR, AND MKG ARE LIFR AND WILL REMAIN LIFR
THROUGH THIS EVENING BEFORE A FRONT SCOURS OUT THE MOISTURE. THE
SOUTHWARD MOVEMENT OF THIS FRONT WILL BRING LIFR CONDITIONS BACK
TO JXN/AZO/BTL FROM LATE AFTERNOON THROUGH LATE EVENING. MVFR
STRATUS SETS UP BEHIND THE FRONT THROUGH THE REST OF THE TAF
PERIOD FOR THE MOST PART. SOME UNCERTAINTY AS TO IF ENOUGH LOW-
LEVEL SUBSIDENCE CAN SCATTER OUT MVFR CIGS FOR A FEW HOURS AFTER
MIDNIGHT AT ALL TERMINALS EXISTS. WINDS WILL SHIFT TO
NORTHWESTERLY THIS EVENING AS THE LOW DRIVING OUR POOR CONDITIONS
MOVES AWAY.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...MEADE
AVIATION...THOMAS
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