397
FXUS63 KGRR 101137
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
737 AM EDT MON AUG 10 2026
KEY MESSAGES
- NUMEROUS STRONG STORMS LIKELY THROUGH DAYBREAK THIS MORNING
- SMALL CHANCES OF MAINLY DIURNAL SHOWERS/STORMS INTO THURSDAY
- BETTER CHANCES OF RAIN RETURN NEXT WEEKEND
DISCUSSION
ISSUED AT 336 AM EDT MON AUG 10 2026
- NUMEROUS STRONG STORMS LIKELY THROUGH DAYBREAK THIS MORNING
WE ARE SEEING THE EFFECTS OF THE SECONDARY LOW LEVEL JET OVER THE
AREA EARLY THIS MORNING IN THE FORM OF NUMEROUS SHOWERS AND STORMS
OVER THE SOUTHERN 2/3RDS OF THE FORECAST AREA. SOME OF THE STORMS
HAVE HAD SOME GOOD UPDRAFTS/CORES ASSOCIATED WITH THEM. FORECAST
SOUNDINGS SHOW THAT THERE IS AN INVERSION FROM AROUND 925MB AND
LOWER, WHICH WILL LIMIT THE ABILITY FOR STRONGER WINDS TO REACH THE
GROUND. SOME WIND WAS PRESENT IN STORMS A COUPLE OF HOURS AGO, SO
THEY WILL BE POSSIBLE.
THE BIGGER THREAT LOOKS TO BE THE HEAVY RAIN POTENTIAL. PRECIPITABLE
WATER VALUES JUST SHORT OF 2.0 INCHES ARE LEADING TO SOME VERY HEAVY
DOWNPOURS. SOME OF THE STORMS EARLIER SAT OVER ONE AREA, AND
PRODUCED OVER 2 INCHES IN JUST OVER AN HOUR IN SW KENT COUNTY.
THE EXPECTATION IS THAT THE STORMS OVER THE AREA THIS MORNING WILL
PUSH OUT TOWARD 12Z OR SO. THIS LINES UP NICELY WITH THE LOW LEVEL
JET PUSHING EAST BY THAT TIME, WITH NO ADDITIONAL FORCING MOVING IN.
THE FRONT IS EXPECTED TO PUSH FAR ENOUGH SOUTH THEN BEHIND THIS
MORNING'S STORMS, THAT AS THE NEXT LOW LEVEL JET RAMPS UP THIS
EVENING, EVERYTHING SHOULD STAY SOUTH OF THE FORECAST AREA. WE CAN'T
RULE OUT A POP UP SHOWER/STORM THIS AFTERNOON WITH PLENTY OF
MOISTURE REMAINING. THE COVERAGE LOOKS TO BE QUITE LOW (<20%) DUE TO
A LACK OF ANY BIG FEATURE TO FORCE IT.
- SMALL CHANCES OF MAINLY DIURNAL SHOWERS/STORMS INTO THURSDAY
WE GET INTO A PATTERN FOR TUESDAY THROUGH THURSDAY NOW WHERE WE WILL
BE LOOKING AT SOME SMALL DIURNAL CHANCES FOR A FEW SHOWERS AND
STORMS EACH AFTERNOON AND EVENING. GENERALLY SPEAKING, WE SHOULD SEE
MU CAPES BUILD TO 1000-2000 J/KG EACH AFTERNOON AND EVENING WITH DEW
POINTS REMAINING IN THE 60S, AND TEMPS IN THE 80S. WEAK SHORT WAVES
IN THE UPPER FLOW FROM THE WNW WILL HELP THE CAUSE ALSO. THERE MAY
BE A LITTLE BIT BETTER CHANCE ACROSS THE FAR SOUTH WHERE INSTABILITY
WILL BE A LITTLE HIGHER DUE TO HIGHER DEW POINTS AND WARMER TEMPS.
THIS INCLUDES THURSDAY NOW, WHERE A FEW RUNS AGO, IT LOOKED LIKE
THURSDAY MAY BE DRY. THIS IS DUE TO A DELAY IN THE BACKDOOR FRONT
DROPPING DOWN, AND CLEARING OUT THE HIGHER DEW POINTS AND
TEMPERATURES. NOW IT LOOKS LIKE IT WILL TAKE UNTIL FRIDAY BEFORE WE
CAN GO WITH A DRY FORECAST.
- BETTER CHANCES OF RAIN RETURN NEXT WEEKEND
THE BREAK IN THE RAIN CHANCES WILL BE SMALL FOR FRIDAY, AS WE SEE A
PATTERN CHANGE TAKE SHAPE BY SATURDAY TO BRING RAIN CHANCES BACK IN.
THE FRONT AND THE HEAT WILL BE LOCKED UP TO OUR SOUTH MUCH OF THIS
WEEK. HOWEVER, A LONG WAVE TROUGH EMERGES OVER THE WESTERN U.S. AND
SHIFTS THE UPPER FLOW TO THE SW FOR OUR AREA. THIS WILL ALLOW ENERGY
TO EJECT FROM THE WESTERN TROUGH, AND LIFT UP TOWARD THE AREA. THE
MODELS HAVE BEEN HINTING AT THIS QUITE CONSISTENTLY, JUST WITH SOME
FLUCTUATIONS IN TRACK AND TIMING.
THE STRONGER SYSTEM WILL TEND TO DRAW BETTER MOISTURE NORTHWARD, AND
THIS WILL BE POSSIBLE AS EARLY AS EARLY AS FRIDAY NIGHT INTO
SATURDAY AT THE LEADING EDGE OF THE MOISTURE ADVECTION. THE SYSTEM
WILL EVENTUALLY MOVE THROUGH, AND PUSH A FRONT THROUGH THAT WILL
SWEEP OUT THE MOISTURE AND WARMER TEMPERATURES.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 737 AM EDT MON AUG 10 2026
THE WIDESPREAD SHOWERS AND STORMS FROM EARLIER THIS MORNING HAVE
JUST ABOUT ALL EXITED THE AREA AS EXPECTED BY NOW. IN THEIR WAKE,
WE HAVE MANY TERMINALS WITH MVFR CEILINGS AND SOME IFR WITH
LINGERING LOW LEVEL MOISTURE IN PLACE. WE WILL SEE THESE CLOUDS
LIFT AND BREAK UP A BIT TO VFR BY LATE THIS AFTERNOON. CAN'T RULE
OUT A POP UP SHOWER THIS AFTERNOON, BUT MOST SITES WILL STAY DRY.
MID CLOUD COVER WILL HOLD ON TONIGHT, AND WINDS WILL GO LIGHT.
THIS WILL SET SITES UP FOR SOME POSSIBLE FOG LATE IN THE PERIOD.
WE ARE EXPECTING SOME LOW END MVFR TO IFR AT MOST SITES.
MARINE
ISSUED AT 336 AM EDT MON AUG 10 2026
IT CONTINUES TO LOOK LIKE THAT WE WILL REMAIN HEADLINE FREE FOR
MARINE INTERESTS FOR MOST OF THIS UPCOMING WEEK. THE GRADIENT
REMAINS RELATIVELY WEAK FOR THE AREA WITH NO MAJOR SYSTEMS EXPECTED
THROUGH FRIDAY. A BIT OF A GRADIENT WILL MOVE IN FROM THE NE BEHIND
A WEAK COLD FRONT THAT DROPS DOWN THROUGH LATE THURSDAY, BUT IT DOES
NOT LOOK STRONG ENOUGH AT THIS TIME TO NEED A HEADLINE.
A BETTER CHANCE FOR WIND AND POSSIBLE HEADLINES WILL COME NEXT
WEEKEND AS WE SEE A BIT BETTER ORGANIZED SYSTEM COME OUT FROM THE
WESTERN U.S. THIS COULD OCCUR AS EARLY AS FRIDAY NIGHT AND MORE
LIKELY INTO SATURDAY.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...NJJ
AVIATION...NJJ
MARINE...NJJ
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