444
FXUS63 KGRR 132332
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
732 PM EDT SAT SEP 13 2025
KEY MESSAGES
- DRY WEATHER THROUGH EARLY NEXT WEEK
- CHANCE OF SHOWERS/STORMS LATE NEXT WEEK
DISCUSSION
ISSUED AT 255 PM EDT SAT SEP 13 2025
- DRY WEATHER THROUGH EARLY NEXT WEEK
THE TROUGH THAT BROUGHT RAINFALL THIS MORNING WILL CONTINUE TO MOVE
SOUTHWARD THIS AFTERNOON WITH DRY AIR FILLING IN BEHIND IT. A
BUILDING HIGH WILL MOVE OVER THE MIDWEST AND DOMINATE THE PATTERN
THROUGH THE UPCOMING WEEK. MODELS REMAIN IN GOOD AGREEMENT AS THE
HIGH WILL BRING FAIR WEATHER WITH WARM AIR ADVECTION THROUGH MID
WEEK.
THE HIGH WILL REMAIN ENTRENCHED OVER THE REGION WITH WEAK FLOW
THROUGH THAT TIME FRAME. WITH 850MB TEMPS INCREASING AS THE WEEK
PROGRESSES, TEMPS AT 850 MB SHOULD BUILD TO UPWARDS OF +20C BY
WEDNESDAY. THAT WILL CORRELATE TO BRINGING MAXIMUM SURFACE TEMPS
FROM SUNDAY THROUGH THURSDAY IN THE MID TO UPPER 80S, WITH 90 NOT
NECESSARILY OUT OF REACH ON WEDNESDAY. THE WARM AND DRY WEATHER
SHOULD LINGER INTO THURSDAY.
- CHANCE OF SHOWERS/STORMS LATE NEXT WEEK
THE HIGH PRESSURE THAT WILL DOMINATE THE FIRST HALF OF THE WEEK
WILL BE EJECTED BY AN UPPER LEVEL LOW AS IT MOVES ALONG THE
CANADIAN BORDER AND THROUGH THE REGION LATE THURSDAY INTO
SATURDAY.
THERE IS SOME DISPARITY IN THE MODELS BUT ENSEMBLES BRING THE
FRONT THROUGH FRIDAY INTO SATURDAY. SOME RUNS MOVE IT QUICKER
DEPENDING ON THE COLD AIR AND THE STRENGTH OF THE HIGH. GIVEN
THOSE CONSIDERATIONS HAVE A BROAD PERIOD OF CHANCE POPS.
CURRENTLY, THERE IS GOOD MID TO LOW LEVEL FORCING WITH THAT
SYSTEM. THE LATEST EC SHOWS THE PRESENCE OF AN LLJ FRIDAY
AFTERNOON. THAT CORRELATES WITH INCREASED CAPE THROUGH THE
ENSEMBLES. SO THERE IS THE POTENTIAL FOR STORMS ALONG THE FRONTAL
BOUNDARY FRIDAY INTO SATURDAY. POSITION, TIMING AND STRENGTH WILL
VARY AS THAT TIMEFRAME MARCHES CLOSER.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 732 PM EDT SAT SEP 13 2025
SHALLOW/PATCHY FOG EARLY SUNDAY MORNING... MEDIUM CONFIDENCE.
HIGH PRESSURE STRENGTHENING OVER THE AREA, AND ITS ASSOCIATED
SINKING AIR THROUGH MUCH OF THE ATMOSPHERE, IS WORKING TO
EVAPORATE THE CLOUDS AT 6,000 FEET. HOWEVER, TROUGHING PERSISTING
AT THAT LEVEL OVERNIGHT IS COUNTERACTING THAT SINKING TENDENCY
TO SOME EXTENT, SO THERE REMAIN NW-SE ORIENTED BELTS OF STUBBORN
CLOUDS AT LEAST FOR PART OF THIS EVENING.
ASSUMING SKIES GO MOSTLY CLEAR, FORECAST LOWS WILL BE CLOSE TO THE
CROSSOVER TEMPERATURE, SO PATCHY OR SHALLOW FOG COULD DEVELOP
(WITH DIPS INTO REPORTED IFR VIS) MAINLY BETWEEN 08 AND 12 Z.
MARINE
ISSUED AT 240 PM EDT SAT SEP 13 2025
PREVAILING WINDS WILL BE LIGHT FROM EAST THE NEXT FEW DAYS, THOUGH
THE DIRECTION MAY FLOP AROUND DURING AFTERNOONS AS THE LAKE BREEZE
PARTIALLY COUNTERACTS THE PREVAILING FLOW. WAVES WILL STAY 1 FOOT OR
LESS.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...CERU
AVIATION...CAS
MARINE...OSTUNO
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