745
FXUS63 KGRR 041049
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
649 AM EDT SUN OCT 4 2026
KEY MESSAGES
- BRIEF PERIOD OF RAIN THIS MORNING
- AREAS OF FROST POSSIBLE TONIGHT AND MONDAY NIGHT
DISCUSSION
ISSUED AT 222 AM EDT SUN OCT 4 2026
- BRIEF PERIOD OF RAIN THIS MORNING
A SHORTWAVE TROUGH IS MOVING THROUGH THIS MORNING WITH PLENTY OF
POSITIVE VORTICITY ADVECTION AND 700 MB FRONTOGENESIS. THESE
SHOWERS ARE ELEVATED AS SEEN IN OBSERVATIONS WITH CLOUD BASES
AROUND 8 TO 10 KFT. AS RADAR TRENDS CONTINUE IT LOOKS LIKE MOST
WILL SEE LIGHT RAIN BEFORE THE 850 MB FRONT CLEARS AROUND 9AM.
DRY CONDITIONS ARE EXPECTED THROUGH THE REMAINDER OF THE FORECAST,
BUT TUESDAY NIGHT INTO WEDNESDAY WILL NEED TO BE MONITORED. A
DECENT LOW LEVEL JET, WARM AIR ADVECTION AHEAD OF THE SHORTWAVE
TROUGH AND FRONT WILL BE PRESENT. THE QUESTION IS WILL THERE BE
ENOUGH MOISTURE. CURRENTLY BETTER CHANCES ARE NORTH OF THE AREA,
BUT THE ENS MEMBERS HIGHLIGHT LIGHT RAIN ACROSS THE FORECAST AREA.
IF THIS TREND CONTINUES, CHANCES FOR PRECIPITATION WILL NEED TO BE
ADDED.
- AREAS OF FROST POSSIBLE TONIGHT AND MONDAY NIGHT
HIGH PRESSURE BUILDS IN TONIGHT AND CONTINUES INTO MONDAY. 925 MB
TEMPERATURES WILL FALL INTO THE 6 TO 8 C RANGE. THE INVERSION THAT
DEVELOPS ISN'T OVERLY STRONG SO EXPECTING INLAND AREAS ALONG AND
NORTH OF U-10 TO HAVE THE BEST CHANCE FOR LOWS DROPPING INTO THE
MID 30S WITH ISOLATED COLDER SPOTS. HOWEVER CONFIDENCE IS NOT HIGH
AT THIS TIME AS THERE HAS BEEN A SLIGHT WARMING TREND IN THE DATA.
IN COORDINATION WITH GAYLORD HELD OFF ON ISSUING A FROST ADVISORY
AT THIS TIME DUE TO THE UNCERTAINTY.
MONDAY NIGHT WILL HAVE A BETTER CHANCE FOR MORE WIDESPREAD FROST
AS LOW TEMPERATURES DROP INTO THE MID TO UPPER 30S ACROSS AREAS
LARGELY EAST OF US-131 AND NORTH OF I-96. THE BEST CHANCES (50
PERCENT) FOR LOWS IN THE LOW TO MID 30S WILL BE INLAND AREAS ALONG
AND NORTH OF US-10.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 649 AM EDT SUN OCT 4 2026
RAIN WILL MOVE OUT OF THE AREA OVER THE NEXT HOUR. CAN'T RULE OUT
A STRAY RUMBLE OF THUNDER SOUTH OF LANSING AND NEAR JACKSON.
OTHERWISE SOUTHERLY WINDS TODAY WILL GRADUALLY SHIFT TO THE WEST
AND THEN NORTHWEST THIS MORNING AND AFTERNOON AS THE FRONT MOVES
THROUGH. GUSTS THIS AFTERNOON ARE EXPECTED TO BE AROUND 20 KNOTS.
LIGHTER NORTHWEST WINDS DEVELOP TONIGHT INTO MONDAY MORNING.
MARINE
ISSUED AT 222 AM EDT SUN OCT 4 2026
WINDS WILL PICK UP FROM THE SOUTHWEST AS THIS MORNING'S RAIN
CLEARS AND THEN SHIFT TO THE WEST AND NORTHWEST DURING THE LATE
MORNING AND AFTERNOON. WAVES BUILD INTO THE 4 TO 7 FOOT RANGE
NORTH OF HOLLAND WITH THE HIGHEST WAVES NORTH OF MUSKEGON. GUSTS
AROUND 20 TO 25 KNOTS MAY LINGER LONGER INTO TONIGHT FOR AREAS
NORTH OF GRAND HAVEN. ADDITIONALLY WAVES MAY APPROACH 4 FEET NEAR
AND SOUTH OF SOUTH HAVEN. THEREFORE THE SMALL CRAFT ADVISORY WILL
LIKELY NEED TO BE ADJUSTED FOR THIS EVENING INTO MONDAY MORNING.
ANOTHER PERIOD OF SMALL CRAFT ADVISORY CONDITIONS LOOKS TO DEVELOP
TUESDAY WITH STRONG SOUTHWESTERLY WINDS. THERE IS THE POTENTIAL
THAT A BRIEF PERIOD OF GALES DEVELOPS TOWARDS LITTLE AND BIG SABLE
TUESDAY AFTERNOON.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ846.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ847>849.
DISCUSSION...RAH
AVIATION...RAH
MARINE...RAH
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