688
FXUS63 KGRR 041744
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
144 PM EDT THU SEP 4 2025
KEY MESSAGES
- STRONG WINDS TO SWEEP THROUGH THE AREA FRIDAY MORNING
- COOL WEATHER THROUGH THE WEEKEND
DISCUSSION
ISSUED AT 356 AM EDT THU SEP 4 2025
- STRONG WINDS TO SWEEP THROUGH THE AREA FRIDAY MORNING
A COMPACT AND FAST-MOVING LOW PRESSURE CENTER WILL TRACK THROUGH THE
MIDWEST AND NORTHERN MICHIGAN TODAY-TONIGHT, TO BECOME INCORPORATED
INTO THE LARGER LOW OVER NORTHERN ONTARIO. THE LOW-LEVEL WIND FIELD
TO THE SOUTH OF THE LOW IS EXPECTED TO BE QUITE STRONG. HREF MEAN
925 MB (APPROX 1500 FEET) SOUTHWESTERLY WINDS PEAK AROUND 40-45
KNOTS OVER OUR AREA BETWEEN 5 AM AND 10 AM. A REASONABLY STABLE
THERMAL PROFILE FROM THE SURFACE TO THAT LAYER WILL BE PRESENT UNTIL
LATE IN THE MORNING, POSSIBLY PREVENTING ADVISORY-LEVEL WIND GUSTS
FROM AFFECTING MOST OF THE AREA. 40-45 MPH WIND GUSTS WOULD BE MOST
FAVORED IN WESTERN PORTIONS OF LAKESHORE COUNTIES AS STRONGER WINDS
OVER THE LAKE MICHIGAN SURFACE COULD SPILL A BIT INLAND. AS A DEEPER
DIURNAL BOUNDARY LAYER BECOMES ESTABLISHED, THE LOW-LEVEL WIND
FIELDS IN THE WAKE OF THE LOW WOULD STILL SUPPORT 30-35 MPH GUSTS
OVER THE LAND LATE MORNING INTO AFTERNOON.
A SHORT PERIOD OF RAIN IN THE WARM ADVECTION PORTION OF THE LOW IS
ALSO EXPECTED, MOSTLY BEFORE DAYBREAK AND MOSTLY TO THE NORTH OF
HOLLAND - GRAND RAPIDS - ALMA. THERE COULD ALSO BE SOME PASSING
SHOWERS LINGERING THROUGHOUT THE REST OF THE DAY.
- COOL WEATHER THROUGH THE WEEKEND
THE ANOMALOUS SYNOPTIC-SCALE TROUGH ANCHORED OVER THE REGION WILL
FINALLY DEAMPLIFY AND MOVE AWAY EARLY NEXT WEEK. SURFACE HIGH
PRESSURE MOVING IN AMID THE LINGERING COLD AIR COULD SET UP FROST
CONCERNS FOR SUNDAY NIGHT TO MONDAY MORNING. TEMPERATURES ARE
FAVORED TO WARM BACK UP INTO THE 70S THE MIDDLE OF NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 144 PM EDT THU SEP 4 2025
THE FIRST 6-10 HOURS OF THE TAF PERIOD WILL BE RELATIVELY QUIET
BEFORE LOW PRESSURE MOVES INTO THE GREAT LAKES REGION. THIS LOW
WILL BRING WIND SHEAR, SCATTERED SHOWERS AND GUSTY SOUTHWEST WINDS
TO LOWER MICHIGAN. SHOWERS SHOULD MOSTLY BE FOCUSED ON A 6 HOUR
OR SO WINDOW 06Z-12Z. WIND SHEAR SHOULD BE AROUND FOR MOST OF THAT
06Z-12Z PERIOD AS WELL AND MAY LINGER THROUGH THE END OF THE TAF
PERIOD EVEN AS SURFACE WINDS MIX OUT AND GUST OVER 25KTS.
MARINE
ISSUED AT 356 AM EDT THU SEP 4 2025
SLIGHT CHANCE OF A WATERSPOUT THIS MORNING AS A FEW LAKE-EFFECT
SHOWERS LINGER ALONG A WIND CONVERGENCE ZONE BETWEEN MUSKEGON AND ST
JOSEPH, BUT THE LOW CONVECTIVE DEPTHS ARE KEEPING THAT THREAT
MARGINAL.
WEST WINDS DURING THE DAY WILL BE COMPARATIVELY RELAXED, THOUGH
WAVES WILL REMAIN MARGINALLY HAZARDOUS FOR SMALL CRAFT AND SWIMMERS.
SOUTHWEST WINDS INCREASE SUBSTANTIALLY TONIGHT, BECOMING GALES TO 40
KNOTS AFTER 2 AM UNTIL LATE FRIDAY MORNING. THE WINDS ARE EXPECTED
TO PEAK AROUND DAYBREAK. HAZARDOUS WINDS AND WAVES FOR SMALL CRAFT
AND SWIMMERS THEN CONTINUE FRIDAY AFTERNOON INTO SATURDAY.
GRR WATCHES/WARNINGS/ADVISORIES
MI...BEACH HAZARDS STATEMENT THROUGH SATURDAY MORNING FOR MIZ037-043-
050-056-064-071.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT FRIDAY FOR LMZ844>849.
GALE WARNING FROM 2 AM TO 11 AM EDT FRIDAY FOR LMZ844>849.
DISCUSSION...CAS
AVIATION...MACZKO
MARINE...CAS
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