103
FXUS63 KGRR 050610
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
210 AM EDT SUN JUL 5 2026
KEY MESSAGES
- POP-UP THUNDERSTORMS THIS AFTERNOON AND EVENING
- SHOWERS AND THUNDERSTORMS MAINLY SOUTH TONIGHT INTO SUNDAY
- DRY MONDAY THROUGH WEDNESDAY, SHOWERS AND THUNDERSTORM CHANCES
RETURN LATE WEDNESDAY NIGHT INTO THURSDAY
DISCUSSION
ISSUED AT 123 PM EDT SAT JUL 4 2026
- POP-UP THUNDERSTORMS THIS AFTERNOON AND EVENING
A SURFACE TROUGH OVER THE AREA AND WEAK COLD FRONT WILL SINK SOUTH
THIS AFTERNOON. ALREADY SEEING BUILDING CUMULUS AND SHOWERS
DEVELOPING NORTH OF I-96. SURFACE BASED CAPE WILL INCREASE TO 1000
TO 1500 J/KG THIS AFTERNOON. SHEAR HOWEVER IS LACKING. THEREFORE NOT
EXPECTING ANYTHING ORGANIZED OR SEVERE, JUST SOME GENERAL POP-UP
THUNDERSTORMS WITH LIGHTNING AND BRIEF HEAVY DOWNPOURS AS THE MAIN
CONCERN. THUNDERSTORMS WILL GENERALLY TAPER OFF AROUND SUNSET WITH
THE CHANCE FOR LINGERING SHOWERS AND STORMS ACROSS SOUTHERN MICHIGAN.
- SHOWERS AND THUNDERSTORMS MAINLY SOUTH TONIGHT INTO SUNDAY
AS MENTIONED SHOWERS AND THUNDERSTORMS COULD LINGER IN SOUTHERN
MICHIGAN OVERNIGHT DUE TO A DISTURBANCE MOVING THROUGH NORTHERN
ILLINOIS UNDER THE SURFACE TROUGH. HREF PROBABILITIES ARE NOT HIGH
THOUGH SO IT IS POSSIBLE THAT AREAS ALONG I-94 COULD REMAIN DRY.
SUNDAY WE'LL SEE ANOTHER DIURNAL TREND WITH STORMS MAINLY FOCUSED
ALONG AND EAST OF A KALAMAZOO TO ST. JOHNS LINE. INSTABILITY WILL
ONLY BE AROUND 1000 J/KG AND WITH SIMILAR SHEAR VALUES TO TODAY DO
NOT EXPECT ANY SEVERE WEATHER.
- DRY MONDAY THROUGH WEDNESDAY, SHOWERS AND THUNDERSTORM CHANCES
RETURN LATE WEDNESDAY NIGHT INTO THURSDAY
HIGH PRESSURE BUILDS IN FOR MONDAY THROUGH WEDNESDAY. THE RIDGE
WEAKENS WEDNESDAY NIGHT WITH AN APPROACHING TROUGH. THERE ARE SOME
TIMING DIFFERENCES WITH THIS SHORTWAVE MOVING THROUGH SOMETIME IN
THE LATE WEDNESDAY NIGHT/THURSDAY TIMEFRAME. THE TIMING WILL IMPACT
WHETHER WE SEE LINGERING RAIN CHANCES FOR FRIDAY OR IF WE'LL SEE DRY
CONDITIONS. OVERALL WITH THIS SYSTEM THERE WILL BE A WEAK LOW LEVEL
JET, AND UPPER LEVEL JET DIVERGENCE MAY BE DISPLACED. OVERALL NOT
SEEING A CONCERN FOR A SEVERE RISK AT THIS TIME.
HIGH TEMPERATURES THROUGH THE WEEK WILL LARGELY BE IN THE 80S WITH
LOWS IN THE 50S AND 60S. A NICE BREAK FROM THE HOT TEMPERATURES
THIS PAST WEEK.
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 220 PM EDT SAT JUL 4 2026
AREAS OF DENSE FOG HAVE DEVELOPED OVER LAKE MICHIGAN IMPACTING THE
LAKESHORE AREAS. EXPECT PERIODS OF REDUCED VISIBILITIES FROM
HOLLAND TO MANISTEE THIS AFTERNOON BEFORE CLEARING THIS EVENING.
THE MARINE DENSE FOG ADVISORY MAY NEED TO BE EXTENDED FURTHER
SOUTH.
THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON AND EVENING BEFORE
TAPERING OFF AROUND SUNSET. WAVES WILL REMAIN BELOW 3 FEET THROUGH
NEXT WEEK. NORTHERLY WINDS SUNDAY AFTERNOON AND MONDAY AFTERNOON MAY
BRIEFLY APPROACH SMALL CRAFT ADVISORY CRITERIA TOWARD BIG AND LITTLE
SABLE. NORTHERLY WINDS ARE LARGELY EXPECTED THROUGH MONDAY WITH
WINDS POTENTIALLY BECOMING EASTERLY EACH NIGHT. TUESDAY WINDS BECOME
WESTERLY THEN SOUTHWESTERLY FOR WEDNESDAY.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...RAH
AVIATION...DUKE
MARINE...RAH
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