402
FXUS63 KGRR 161857
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
257 PM EDT TUE SEP 16 2025
KEY MESSAGES
- PATCHY DENSE FOG AGAIN TONIGHT
- NEXT CHANCE OF RAIN THIS WEEKEND
DISCUSSION
ISSUED AT 256 PM EDT TUE SEP 16 2025
- PATCHY DENSE FOG AGAIN TONIGHT
CONTINUED LIGHT EAST FLOW WILL ALLOW FOR ANOTHER AREA OF FOG TO
FORM ACROSS THE EASTERN ZONES AGAIN LATE TONIGHT AND PERSISTING
FOR AN HOUR OR SO AFTER SUNRISE ON WEDNESDAY. CURRENT DEW POINT
AND TEMPERATURE FORECAST SUGGESTS FOG WILL BE AS EXTENSIVE BUT
PERHAPS NOT AS DENSE AS LAST NIGHT.
- NEXT CHANCE OF RAIN THIS WEEKEND
BLOCKING PATTERN FINALLY BREAKS DOWN THIS WEEKEND WITH THE UPPER
RIDGE BEING REPLACED BY SHORTWAVE TROUGHING BY EARLY NEXT WEEK.
MODEL GUIDANCE AGREES ON THE GENERAL PATTERN BUT SHOWS QUITE A
BIT OF ENSEMBLE SPREAD AND RUN TO RUN INSTABILITY IN THE DETAILS.
CHANCE POPS LOOK GOOD FOR NOW SUNDAY AND MONDAY AS TWO SEPARATE
WAVES MOVE ALONG A SLOW MOVING BAROCLINIC ZONE. LOW CONFIDENCE
FORECAST CONTINUES FOR NEXT WEEK GIVEN DIVERGENT FORECASTS OF THE
UPPER AND SFC PATTERN WITH THE POTENTIAL FOR ANOTHER BLOCKING
PATTERN TO BECOME ESTABLISHED.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 122 PM EDT TUE SEP 16 2025
THIS AFTERNOON THROUGH EARLY WEDNESDAY MORNING WILL FEATURE LITTLE
IN THE WAY OF AVIATION CONCERNS WITH JUST A FEW HIGH CLOUDS AND
WINDS OF 5 KNOTS OR LESS. GUIDANCE CONTINUES TO SUGGEST THAT FOG
WILL DEVELOP ASSOCIATED WITH EASTERLY FLOW OFF OF ERIE AND HURON
AFTER 09-10Z. LOW STRATUS MAY ALSO DEVELOP, PARTICULARLY AT
LAN/JXN. CONDITIONS WILL BE WORST AT LAN AND JXN WHERE LIFR
CONDITIONS ARE POSSIBLE, WITH IFR FOR AZO/BTL AND POSSIBLY GRR
BEING FARTHER FROM THE MOISTURE SOURCE. FOG WILL BURN OFF AN HOUR
OR TWO AFTER SUNRISE RETURNING CONDITIONS TO VFR.
MARINE
ISSUED AT 256 AM EDT TUE SEP 16 2025
MARINE WEATHER LOOKS TO BE BENIGN THROUGH THE REST OF THE WEEK.
SIMILAR TO TODAY, PREDOMINANTLY EASTERLY FLOW WILL BECOME WESTERLY
IN THE AFTERNOON WEDNESDAY AS THE LAKE BREEZE DEVELOPS. WINDS
INCREASE TO 10-15 KNOTS LATER THURSDAY BUT IMPACTS WILL BE LOW WITH
NORTHEASTERLY FLOW BEING PREDOMINANTLY OFFSHORE. AN APPROACHING LOW
PRESSURE SYSTEM INCREASES WINDS TO 15-20 KNOTS SATURDAY MORNING,
HOWEVER ONCE AGAIN FLOW LOOKS TO BE OFFSHORE. WAVES WILL BE 2 FEET
OR LESS THROUGH THIS PERIOD. CONDITIONS WILL BE QUIET THROUGH FRIDAY
WITH A 20 TO 40 PERCENT CHANCE OF SHOWERS THROUGH THE WEEKEND.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...OSTUNO
AVIATION...THOMAS
MARINE...THOMAS
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