575
FXUS63 KGRR 220524
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
124 AM EDT TUE APR 22 2025
KEY MESSAGES
- WINDS DECREASING OVERNIGHT
- SEVERAL CHANCES FOR SHOWERS MID WEEK
- WARM AND WET FRIDAY INTO SATURDAY, DRY SUNDAY
DISCUSSION
ISSUED AT 309 PM EDT MON APR 21 2025
- WINDS DECREASING OVERNIGHT
WATER VAPOR IMAGES SHOW A SECONDARY UPPER PV MAX THAT HAS JUST
CROSSED THE MILWAUKEE AREA AND ENTERED SOUTHERN LAKE MICHIGAN. THIS
HAS BEEN ASSOCIATED WITH CONTINUED GUSTS IN EXCESS OF 35 KNOTS. SO,
IT DEFINITELY SEEMS PRUDENT TO KEEP THE WIND ADVISORY IN EFFECT AS
CURRENTLY SCHEDULED FOR NOW - ALTHOUGH IT CAN LIKELY BE CANCELLED
PRIOR TO THE SLATED 10 PM EXPIRATION TIME. WILL DEFER TO THE EVENING
SHIFT TO HAMMER OUT THESE DETAILS.
- SEVERAL CHANCES FOR SHOWERS MID TO LATE WEEK
SHORTWAVE RIDGING ALOFT WILL INTRODUCE ASSOCIATED SURFACE PRESSURE
RIDGING ACROSS THE WESTERN GREAT LAKES FOR MUCH OF TUESDAY. HOWEVER,
AS NOTED PREVIOUSLY WE ARE LOOKING AT A WARM FRONT LIFTING NORTH
TOWARDS LOWER MICHIGAN. THERE WILL BE A BAND OF STRONGER WESTERLY
FLOW ALOFT IN THE VICINITY, INDICATIVE OF MORE ISENTROPIC SLOPING
UNDERNEATH. WAVINESS IN THE MID-LEVEL FLOW WILL INDUCE ISENTROPIC
ASCENT WITHIN THIS SLOPED REGIME, LIKELY CULMINATING IN A BAND OF
SHOWERS AND PERHAPS EVEN STORMS AROUND OR SOUTH OF THE I-94 CORRIDOR
BEGINNING AS EARLY TUESDAY EVENING. GIVEN THE ELEVATED NATURE OF
PRECIPITATION AND EPHEMERAL ASPECTS OF THE FORCING, FORECAST
CERTAINTY WILL BE VERY LIMITED DURING THIS TIME FRAME.
- WARM AND WET FRIDAY INTO SATURDAY, DRY SUNDAY
THERE IS BETTER FORECAST CERTAINTY FOR SHOWERS AND THUNDERSTORMS TO
OVERSPREAD THE AREA DURING THIS TIME AS A WELL PHASED UPPER TROUGH
TRAVERSES THE AREA. UPPER MESOSCALE RIDGING AHEAD OF THE TROUGH
COMBINED WITH PLACEMENT IN THE WARM SECTOR MAY ALLOW HIGHS ON
THURSDAY TO MAKE A RUN TOWARDS 80 DEGREES ACROSS MUCH OF SOUTHWEST
LOWER MI.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 123 AM EDT TUE APR 22 2025
VFR CONDITIONS WITH WINDS BLO 10 KNOTS THROUGH TUESDAY EVENING.
SOME SCATTERED SHOWERS COULD REACH MKG DURING THE AFTERNOON BUT
VFR CONDITIONS SHOULD STILL PREVAIL.
MARINE
ISSUED AT 309 PM EDT MON APR 21 2025
NO CHANGES TO THE GALE WARNING AT THIS TIME. THIS WILL EVENTUALLY
NEED TO BE REPLACED WITH A SMALL CRAFT ADVISORY SINCE WAVES WILL
MEET OR EXCEED THOSE CRITERIA MUCH OF TONIGHT.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT EARLY THIS MORNING FOR
LMZ844>849.
DISCUSSION...TJT
AVIATION...OSTUNO
MARINE...TJT
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