040
FXUS63 KGRR 240002
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
802 PM EDT THU JUL 23 2026
KEY MESSAGES
- DRY THROUGH SATURDAY MORNING
- PERIODS OF SHOWERS/STORMS POSSIBLE SATURDAY NIGHT INTO TUESDAY
- TEMPERATURES WARMING INTO SUNDAY/MONDAY
DISCUSSION
ISSUED AT 248 PM EDT THU JUL 23 2026
- DRY THROUGH SATURDAY MORNING
HIGH PRESSURE WILL DOMINATE THE AREA WEATHER TONIGHT THROUGH
SATURDAY MORNING. VERTICAL PROFILES SHOW A DISTINCT LACK OF
MOISTURE THROUGH THAT TIME OUTSIDE OF SOME OCCASIONAL CUMULUS
LEVEL MOISTURE. WE ARE LOOKING AT MOSTLY CLEAR TO PARTLY CLOUDY
CONDITIONS THROUGH SATURDAY MORNING. LOWS IN THE 50S AND HIGHS
AROUND 80 WILL BE COMMON THROUGH SATURDAY.
- PERIODS OF SHOWERS/STORMS POSSIBLE SATURDAY NIGHT INTO TUESDAY
THE FIRST QUESTION DURING THIS PERIOD IS WHEN DO SHOWERS AND
THUNDERSTORMS FIRST MAKE IT BACK INTO THE FORECAST. IT STILL
APPEARS TO BE SATURDAY NIGHT, BUT THERE IS A PUSH OF MOISTURE AND
THEREFORE MUCAPE INTO SOUTHWEST LOWER MICHIGAN SATURDAY AFTERNOON
AND EVENING. THE NAM IS MORE BULLISH ON THIS, BUT EVEN THE ECMWF
AND GFS HAVE MUCAPE VALUES INTO THE 500-1000 J/KG RANGE. PWATS
SURGE TO 1.5+ INCHES DURING THE SAME TIME. WE WILL BE WATCHING
THIS TIME FRAME CLOSELY AS MANY HAVE SUMMER ACTIVITIES GOING ON.
THE PATTERN FROM SATURDAY NIGHT THROUGH TUESDAY IS DOMINATED BY
NORTHWEST UPPER FLOW BETWEEN A PLAINS RIDGE AND A LOW CENTERED
NEAR HUDSON BAY MUCH OF THE TIME. LOW LEVEL MOISTURE WILL BE BACK
IN PLACE WHICH WILL MAKE PERIODIC THUNDERSTORMS POSSIBLE EACH
FORECAST PERIOD. TRYING TO NAIL DOWN THE MORE LIKELY PERIODS FOR
SHOWERS AND STORMS IS THE CHALLENGE. THE TWO MAIN FOCUS PERIODS
ARE SUNDAY AFTERNOON AND EVENING AND AGAIN MONDAY AFTERNOON AND
EVENING. THE UPPER SHORTWAVES ARE SUBTLE BUT IT APPEARS THE MONDAY
WAVE MAY BE THE STRONGER ONE. THE ECWMF WITH THE MONDAY WAVE
PRODUCES A FAIRLY DEEP SURFACE LOW, SWEEPING A 994MB LOW THROUGH
THE GREAT LAKES. MID LEVEL FLOW SURGES ABOVE 50 KNOTS AT TIMES AS
WELL. SO, AT THIS POINT IT LOOKS LIKELY THAT WE WILL SEE PERIODIC
STORMS DURING THIS PERIOD WITH THE THREAT OF SEVERE WEATHER AS
WELL. SUNDAY AND MONDAY WOULD BE THE TWO HIGHEST LIKELIHOOD DAYS
FOR THE POTENTIAL OF STRONG TO SEVERE STORMS. LOCALLY HEAVY RAIN
WILL BE POSSIBLE AS WELL GIVEN MID SUMMER MOISTURE IN PLACE.
- TEMPERATURES WARMING INTO SUNDAY/MONDAY
TEMPERATURES WILL WARM FROM AROUND 80 TODAY AND FRIDAY TO AROUND
90 SUNDAY INTO MONDAY. 850MB TEMPERATURES WARM TO AROUND +22C ON
MONDAY. THE WARM TEMPERATURES WILL COMBINE WITH SUMMER MOISTURE TO
PRODUCE MAX APPARENT TEMPERATURES INTO THE 90S. THE HIGHEST
APPARENT TEMPERATURES SURGE TO 98 IN THE SOUTHEAST CWA NEAR
JACKSON ON MONDAY.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 746 PM EDT THU JUL 23 2026
VFR CONDITIONS WILL DOMINATE THE PATTERN THROUGH THE FORECAST
PERIOD. STILL EXPECTING WINDS TO GO CALM THIS EVENING. THOUGH
WINDS WILL MIX OUT TOMORROW MORNING WINDS WILL OVERALL REMAIN 5
KTS OR LESS.
MARINE
ISSUED AT 248 PM EDT THU JUL 23 2026
HIGH PRESSURE IS CENTERED OVER THE GREAT LAKES THIS AFTERNOON AND
WILL REMAIN IN PLACE THROUGH FRIDAY AFTERNOON. FRIDAY NIGHT INTO
SATURDAY THE HIGH SLIDES OFF TO THE EAST AND SOUTHWEST RETURN FLOW
BEGINS ON THE BACKSIDE OF THE HIGH. WINDS AND WAVES WILL BE SUB
ADVISORY LEVEL THROUGH FRIDAY. IN THE RETURN FLOW WE COULD FLIRT
WITH BEACH HAZARD STATEMENT AND SMALL CRAFT ADVISORY LEVELS FROM
ABOUT WHITEHALL TO THE NORTH. AT THIS POINT, WE ARE THINKING 2-4
FEET AND A MODERATE SWIM RISK, BUT WE WILL BE WATCHING. SOUTHERN
ZONES, SOUTH OF GRAND HAVEN, SHOULD SEE MORE OF A 1-3 FOOT ON
SATURDAY.
SUNDAY AFTERNOON AND EVENING COULD BE ANOTHER TIME FRAME WHERE
WINDS AND WAVES ARE UP IN SOUTHWEST FLOW AND AIDED BY
THUNDERSTORMS.
THUNDERSTORMS WILL POSE A HAZARD TO MARINERS AND BEACH GOERS ALIKE
PERIODICALLY FROM SATURDAY NIGHT INTO EARLY NEXT WEEK.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...DUKE
AVIATION...CERU
MARINE...DUKE
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