951
FXUS63 KGRR 182318
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
618 PM EST THU DEC 18 2025
KEY MESSAGES
- RAIN CHANGING TO SNOW SHOWERS TONIGHT, WINDY
- UP/DOWN TEMPS THROUGH WEEKEND, THEN WARMER
DISCUSSION
ISSUED AT 300 PM EST THU DEC 18 2025
- RAIN CHANGING TO SNOW SHOWERS TONIGHT, WINDY
BASED ON UPDATED SNOW ACCUMULATIONS AND EXPECTED WIND, WE INCLUDED
ALL OF THE LAKE SHORE COUNTIES PLUS KALAMAZOO COUNTY IN THE WINTER
WEATHER ADVISORY.
REGIONAL RADAR SHOWS A BAND OF RAIN INCLUDING A NARROW COLD
FRONTAL RAIN BAND MOVING ACROSS EASTERN WISCONSIN AND ILLINOIS.
THIS RAIN WILL MOVE OVER THE CWA THIS EVENING JUST AHEAD OF THE
COLD FRONT. H8 TEMPS NEAR +8C WILL QUICKLY FALL TO -14C BY 06Z. WE
EXPECT LAKE EFFECT SNOW TO DEVELOP AROUND 03Z AND CONTINUE INTO
FRIDAY MORNING. AS BOUNDARY LAYER WINDS TRANSITION FROM WEST TO
NORTHWEST, SNOW WILL IMPACT ALL OF THE LAKE SHORE. GUSTY WINDS
WILL CONTINUE TONIGHT INFO FRIDAY MORNING AS HIGH PRESSURE RUSHES
IN BEHIND THE FRONT. 3HR MSL PRESSURE CHANGES INCREASE FROM
2-3MB/3 HR TO 5-6MB/3HR BY 15Z FRIDAY. STRONGEST WINDS WINDS WILL
BE ALONG THE LAKE SHORE AND GUST TO 40 MPH. TRAVEL IMPACTS ARE
EXPECTED AS THE SNOW AND WIND COMBINE TO PRODUCE BLOWING/DRIFTING.
ACCUMS ALONG THE LAKE SHORE WILL RANGE FROM 1-3 INCHES NORTH OF
MUSKEGON TO 2-4 SOUTH OF THERE. ELSEWHERE, ACCUMULATIONS AROUND A
HALF INCH ARE POSSIBLE.
THE CORE OF THE COLD AIR MOVES OUT QUICKLY AFTER 18Z FRIDAY AND
THE SNOW WILL END.
- UP/DOWN TEMPS THROUGH WEEKEND, THEN WARMER
HIGHS FRIDAY WILL BE IN THE MID 20S. BY SATURDAY, SOUTHWEST WINDS
AHEAD OF THE NEXT SHORT WAVE WILL PUSH TEMPERATURES INTO THE MID
30S. LIGHT SNOW IS POSSIBLE WITH THE SHORT WAVE NORTH OF I-96 BUT
LITTLE IN THE WAY OF ACCUMULATIONS ARE EXPECTED. BEHIND THE SHORT
WAVE SUNDAY, TEMPERATURES WILL BE IN THE LOWER 20S.
SUNDAY LOOKS DRY WITH HIGH PRESSURE IN CONTROL. A BUILDING HIGH
OVER THE CENTRAL US WILL SEND HEIGHTS AND TEMPERATURES UPWARD NEXT
WEEK FROM THE 30S MONDAY TO THE 40S TUESDAY THROUGH CHRISTMAS.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 618 PM EST THU DEC 18 2025
THE PRE AND ALONG FRONTAL RAIN SHOWERS HAVE BROUGHT IFR CIGS AND A
MIX OF IFR AND MVFR VISBYS TO THE TERMINALS WHICH WILL CONTINUE
UNTIL THE FRONT CLEARS THE TERMINALS. AS THE FRONT MOVES THROUGH
FROM WEST TO EAST OVER THE NEXT SEVERAL HOURS, CIGS WILL LIFT TO
SUB FUEL-ALTERNATE MVFR AND REMAIN THERE THROUGH THE REST OF THE
TAF PERIOD. LAKE EFFECT SNOW SHOWERS THEN DEVELOP WITH INITIAL
MVFR FOLLOWED BY IFR FAVORED AT MKG AND AZO WHICH ARE IN THE
FAVORED SNOWBELTS FOR THIS FLOW PATTERN. FURTHER INLAND AT
GRR/BTL, LOWER CONFIDENCE IN IFR IMPACTS HAS LED TO PROB30S FOR
NOW FOR IFR CONDITIONS WITH PREVAILING MVFR. MVFR CONDITIONS ARE
ALSO LIKELY AT LAN/JXN WHEN SNOWBANDS REACH THE TERMINALS. SNOW
WINDS DOWN EARLY FRIDAY AFTERNOON WITH MVFR CIGS PREVAILING
THROUGH THE END OF THE TAF PERIOD. GUSTS TO 30 KNOTS TONIGHT FROM
THE WEST TO WEST NORTHWEST MAY ALSO SUPPORT AREAS OF BLOWING SNOW
FURTHER REDUCING VISIBILITIES.
MARINE
ISSUED AT 300 PM EST THU DEC 18 2025
A GALE WARNING REMAINS IN EFFECT UNTIL 7 AM, AT WHICH TIME A SMALL
CRAFT ADVISORY WILL BE NEEDED. IT'S POSSIBLE THAT THE GALE WARNING
WILL BE EXTENDED A FEW HOURS FRIDAY MORNING. A TIGHT PRESSURE
GRADIENT IS IN PLACE AS DEEP LOW PRESSURE MOVES THROUGH THE GREAT
LAKES WHICH IS PRODUCING THE STRONG WINDS. WIND AND WAVES WILL BE
HAZARDOUS TO SMALL CRAFT THROUGH THE WEEKEND.
GRR WATCHES/WARNINGS/ADVISORIES
MI...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
FRIDAY FOR MIZ037-038-043-050-056-064-071-072.
MARINE...GALE WARNING UNTIL 7 AM EST FRIDAY FOR LMZ844>849.
DISCUSSION...04
AVIATION...THOMAS
MARINE...04
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