894
FXUS63 KGRR 140648
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
248 AM EDT MON SEP 14 2026
KEY MESSAGES
- SHOWERS AND STORMS TUESDAY, HEAVY RAIN AND ISOLATED SEVERE POSSIBLE
- LOW PREDICTABILITY HEAVY RAIN POSSIBLE INTO THE WEEKEND
DISCUSSION
ISSUED AT 247 AM EDT MON SEP 14 2026
- SHOWERS AND STORMS TUESDAY, HEAVY RAIN AND ISOLATED SEVERE POSSIBLE
CONDITONS SHOULD BE DRY TODAY WITH HIGH PRESSURE IN PLACE ACROSS THE
AREA, BEFORE A LOW DEEPENING IN THE RRQ OF AN UPPER-LEVLE JET WILL
DRIVE A WARM FRONT ACROSS THE AREA EARLY TUESDAY WITH A COLD FRONT
LATER TUESDAY BRINGING SHOWER AND THUNDERSTORM POTENTIAL. LOW-LEVEL
DESTABILIZATION IN CONJUNCTION WITH INCREASED SHEAR FROM A WESTERLY
JET WILL SUPPORT A LOW CHANCE FOR GUSTY WINDS SOUTH OF I96.
DEPENDING ON WHERE THE BOUNDARY STALLS, PWATS OVER 2.0" WILL BE
SUPPORTIVE OF A HEAVY RAIN THREAT AS WELL, SUBJECT TO THAT
PLACEMENT.
- LOW PREDICTABILITY HEAVY RAIN POSSIBLE INTO THE WEEKEND
PREDICTABILITY FALLS INTO MID TO LATE WEEK AS THE FRONT STALLS JUST
SOUTH OF THE AREA, WITH AN UPPER-LEVEL PATTERN DOMINATED BY ZONAL
FLOW WITH EMBEDDED SHORTWAVES. THESE PATTERNS ARE NOTORIOUSLY HARD
TO PIN DOWN. CLUSTER ANALYSIS SUGGESTS WHILE THERE MAY BE DRY
PERIODS, THERE'S NOT GREAT CONFIDENCE AS TO WHEN THEY WILL BE. A
STALLED BOUNDARY WITH PERSISTENT HIGH PWATS FAVORS THE HEAVY RAIN
THREAT CONTINUING WITH A WPC MARGINAL TO SLIGHT ERO IN PLACE.
ANOTHER MID-LEVEL WAVE, LOW-LEVEL JET, AND SURFACE LOW FALL INTO
PLACE GOING INTO THIS WEEKEND. THIS WILL BRING ADDITIONAL
SHOWER/THUNDERSTORM POTENTIAL.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 125 AM EDT MON SEP 14 2026
SKIES ARE GENERALLY CLEAR AREAWIDE WITH THE EXCEPTION OF LAKE
EFFEC STRATOCU AFFECTING MKG. SATELLITE TRENDS SUGGEST THIS SHOULD
LARGELY BE FEW TO SCT, WITH INTERMITTENT CIGS AROUND 5KFT
POSSIBLE AT TIMES. CLOUDS THEN INCREASE IN COVERAGE MONDAY
AFTERNOON AND NIGHT WITH CLOUD BASES LOWERING TO NEAR 10KFT BY THE
END OF THE TAF WINDOW. LIGHT AND VARIABLE WINDS ARE EXPECTED
TONIGHT BEFORE INCREASING FROM THE SOUTHEAST MONDAY AFTERNOON AND
NIGHT.
MARINE
ISSUED AT 247 AM EDT MON SEP 14 2026
CONDITONS DETERIORATE TONIGHT INTO TUESDAY AS AN APPROACHING SURFACE
LOW DEEPENS INCREASING SOUTHERLY FLOW. ENOUGH OF A SIGNAL FOR 35-40
KNOT GALES EXISTS NORTH OF HOLLAND TO HOIST A GALE WARNING, WITH A
SMALL CRAFT ADVISORY SOUTH OF HOLLAND FOR 22-33 KNOT GUSTS. GALES
PERSIST INTO TUESDAY MORNING WITH CONDITIONS HAZARDOUS TO SMALL
CRAFT CONTINUING INTO TUESDAY NIGHT. WILL ALSO HOIST A BEACH HAZARDS
STATEMENT FROM ALLEGAN COUNTY NORTH FOR WAVES AS HIGH AS 12 FEET.
WILL LEAVE VAN BUREN COUNTY OUT FOR NOW WITH THE CAVEAT A 10-20
DEGREE ON SHORE WIND SHIFT WILL BRING WAVES FROM THE 2-4 FT TO 3-5
FT RANGE BRINGING A HIGH SWIM RISK.
GRR WATCHES/WARNINGS/ADVISORIES
MI...BEACH HAZARDS STATEMENT FROM THIS EVENING THROUGH TUESDAY
EVENING FOR MIZ037-043-050-056.
BEACH HAZARDS STATEMENT FROM THIS EVENING THROUGH TUESDAY
AFTERNOON FOR MIZ064.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 5 PM EDT TUESDAY
FOR LMZ844-845.
GALE WARNING FROM 10 PM THIS EVENING TO 8 AM EDT TUESDAY FOR
LMZ846>849.
DISCUSSION...THOMAS
AVIATION...THOMAS
MARINE...THOMAS
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