469
FXUS63 KGRR 210556
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
156 AM EDT SUN JUN 21 2026
KEY MESSAGES
- RAIN CHANCES TONIGHT AND WEDNESDAY
DISCUSSION
ISSUED AT 155 AM EDT SUN JUN 21 2026
- RAIN CHANCES TONIGHT AND WEDNESDAY
THE GREAT LAKES REGION WILL CONTINUE TO BE IN A FAST QUASI-ZONAL
FLOW REGIME ON THE SOUTHERN EDGE OF PERSISTENT UPPER TROUGHING
ACROSS EASTERN CANADA THIS WEEK. THIS WILL KEEP TEMPERATURES
BELOW NORMAL WITH FAST-MOVING SHORTWAVE TROUGHS BRINGING THE
CHANCE FOR RAIN TONIGHT AND AGAIN ON WEDNESDAY.
THE BEST CHANCE FOR RAIN TONIGHT WILL BE ACROSS SOUTHERN LOWER
MICHIGAN AS LOW PRESSURE TRACKS ACROSS NORTHERN INDIANA AND OHIO.
AN AREA OF MID-LEVEL FRONTOGENETIC FORCING BRINGS STEADY RAIN
ACROSS THE I-94 CORRIDOR WITH QPF CLOSE TO AN INCH BY THE TIME
THE RAIN ENDS ON MONDAY. THERE WILL BE A SHARP GRADIENT TO THE
NORTH WITH AROUND A QUARTER INCH ALONG I-96 AND LESS THAN A TENTH
OF AN INCH NORTH OF THERE.
A WEAKER LOW FOLLOWS FOR WEDNESDAY IN NORTHWEST FLOW AND PRECIP
AMOUNTS WILL PROBABLY BE LESS THAN A QUARTER INCH.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 156 AM EDT SUN JUN 21 2026
EXCEPT FOR THE POSSIBILITY OF SHALLOW GROUND FOG BEFORE SUNRISE,
VFR CONDITIONS ARE EXPECTED THIS MORNING BEFORE CLOUDS AND RAIN
MOVE IN FROM THE SOUTHWEST THIS EVENING. MVFR CONDITIONS IN
SHOWERS AND LOWERING CEILINGS ARE EXPECTED THIS EVENING AND
PATCHY IFR IS POSSIBLE, ESPECIALLY ACROSS SOUTHERN LOWER MICHIGAN.
MARINE
ISSUED AT 156 AM EDT SUN JUN 21 2026
FAIRLY TRANQUIL CONDITIONS TODAY THEN WINDS AND WAVES WILL
INCREASE TONIGHT AS LOW PRESSURE PASSES JUST SOUTH OF LAKE
MICHIGAN. A SCA WILL BE NEEDED FOR MONDAY.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...
AVIATION...OSTUNO
MARINE...OSTUNO
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