807
FXUS63 KGRR 050817
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
417 AM EDT SUN JUL 5 2026
KEY MESSAGES
- CHANCES FOR THUNDERSTORMS ONCE AGAIN TODAY
- DRY WEATHER MONDAY NIGHT THROUGH WEDNESDAY
- SHOWERS AND STORMS POSSIBLE WEDNESDAY NIGHT AND THURSDAY
DISCUSSION
ISSUED AT 415 AM EDT SUN JUL 5 2026
- CHANCES FOR THUNDERSTORMS ONCE AGAIN TODAY
MULTIPLE MESO VORTICITY MAXIMA HAVE ROTATED EASTWARD ACROSS
NORTHERN INDIANA TONIGHT. THIS HAS PRODUCED A ZONE OF CONVERGENCE
OVER FAR SOUTHERN LOWER MICHIGAN, INCLUDING THE I-94 CORRIDOR. THE
FV3 SEEMS TO HAVE THE BEST HANDLE ON THIS AND WE EXPECT TO SEE AN
UPTICK IN COVERAGE AND INTENSITY OVER THE NEXT FEW HOURS OR
THROUGH 12Z-13Z. DEEP LAYER SHEAR IS VERY WEAK AND INSTABILITY IS
NOT STRONG (500-1000 J/KG). SO, WHILE WE EXPECT A FEW STORMS EARLY
THIS MORNING WE ARE NOT ANTICIPATING ANYTHING CLOSE TO SEVERE.
A SURFACE LOW WILL BE JUST SOUTH OF THE REGION TODAY OVER IN/OH.
THERE MAY BE JUST ENOUGH LIFT AND INSTABILITY TO SEE ANOTHER SMALL
ROUND OF STORMS THIS AFTERNOON AND EVENING FROM HOLLAND TO ST.
JOHNS SOUTHWARD. THE HREF SHOWS THIS WELL. CANNOT RULE OUT SOME
LOCALLY HEAVY RAIN TODAY NEAR I-94 WITH THE HREF INDICATING SOME
LOCALIZED SWATHS OF 2-4 INCHES POSSIBLE. MOST AREAS WILL NOT SEE
THIS MUCH, BUT WITH CONVERGENCE AND HIGH PWATS THESE VALUES ARE
REASONABLE IN AN ISOLATED MAX FORECAST.
CHANCES FOR SHOWERS WILL PERSIST TONIGHT AND INTO MONDAY ACROSS
THE FAR SOUTHERN CWA AS THE LOW TO OUR SOUTH DOES NOT MOVE MUCH.
- DRY WEATHER MONDAY NIGHT THROUGH WEDNESDAY
WE LOOK TO BE DRY MONDAY NIGHT THROUGH WEDNESDAY WITH HIGH
CONFIDENCE IN RIDGING PERSISTING OVER THE GREAT LAKES. BUFKIT
OVERVIEWS SHOW VERY LITTLE MOISTURE IN THE PROFILE. HIGHS IN THE
80S AND LOWS IN THE 60S WILL FEEL MORE COMFORTABLE, ESPECIALLY
WITH LOWER DEW POINT AIR SETTLING IN ON NORTHEAST WINDS.
- SHOWERS AND STORMS POSSIBLE WEDNESDAY NIGHT AND THURSDAY
OUR NEXT CHANCE FOR RAIN WILL COME WEDNESDAY NIGHT AND THURSDAY AS
A COLD FRONT PRESSES IN FROM THE NORTHWEST. SURFACE DEW POINTS
WILL REBOUND TO 65F TO 70F WHICH WILL PUSH MUCAPE VALUES TO IN
EXCESS OF 1000 J/KG. THUNDERSTORMS WILL CERTAINLY BE POSSIBLE ONCE
AGAIN DURING THIS TIME FRAME.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 210 AM EDT SUN JUL 5 2026
QUITE A BIT OF AVIATION WEATHER TO TALK ABOUT THIS MORNING. FIRST
ORDER OF BUSINESS IS THE CHANCE FOR SHOWERS AND THUNDERSTORMS AT
THE I-94 TAF SITES THROUGH ROUGHLY 12Z OR SO. A COMPACT MID LEVEL
DISTURBANCE ROTATING EAST ACROSS NORTHERN INDIANA MAY PROVIDE LIFT
ALONG I-94, ENOUGH THAT SHOWERS AND STORMS WILL BE GENERATED. AT
THIS POINT HAVE HIT THE AZO TAF SITE THE HARDEST, BUT WE MAY NEED
TO EXPAND THE THREAT TO BTL AND JXN AS WELL.
NEXT ITEM IS THE THREAT AND EXPANDING AREA OF STRATUS THIS
MORNING. THE STRATUS AND LIGHT FOG LOOKS TO EXPAND BEFORE DAYBREAK
TO AFFECT MOST OF THE TAF SITES BY 12Z. THE EXCEPTION MAY BE MKG.
THE STRATUS AND FOG MAY TAKE MOST OF IF NOT ALL OF THE MORNING TO
LIFT. VFR WEATHER IS THEN EXPECTED IN THE MID TO LATE AFTERNOON.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AFTER
ABOUT 20Z.
MARINE
ISSUED AT 415 AM EDT SUN JUL 5 2026
WINDS FOR THE MOST PART WILL BE LIGHT OVER THE NEXT 4 DAYS. THERE
WILL BE SOME STRONGER OFF SHORE WINDS TONIGHT IN THE 10-20 KNOT
RANGE, BUT THEY WILL BE NORTHEAST/OFF SHORE. THEREFORE, WAVES
OVER THE NEXT 4 DAYS IN WEST MICHIGAN WILL LARGELY BE 2 FEET OR
LESS IN THE NEARSHORE WATERS.
THE ONE ITEM TO WATCH IN THE NEXT FEW DAYS IS THAT MONDAY COULD
FEATURE OUR ADVANCING HIGH SCENARIO WHERE WE SEE HIGHER THAN
FORECAST WINDS AND WAVES. IT WOULD BE CENTERED ON MONDAY AFTERNOON
AND EARLY EVENING.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...DUKE
AVIATION...DUKE
MARINE...DUKE
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