209
FXUS63 KGRR 070523
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
123 AM EDT TUE MAY 7 2024
KEY MESSAGES
- POTENTIAL FOR STRONG/SEVERE STORMS TUESDAY
- WET AND COOL WEATHER FOR THE END OF THE WEEK
UPDATE
ISSUED AT 1056 PM EDT MON MAY 6 2024
A FAIRLY QUIET REMAINDER OF THE NIGHT IS EXPECTED WITH HIGH
PRESSURE IN CONTROL OF OUR AREA WEATHER. CHANGES ARE EXPECTED ON
TUESDAY AS THE HIGH SLIDES AWAY TO THE EAST, WHICH WILL ALLOW A
WARM FRONT TO MOVE IN FROM THE SOUTH. FOR THE REST OF THE NIGHT
HOWEVER WE ARE LOOKING AT A GRADUAL INCREASE IN CLOUDS FROM THE
SOUTH AND WEST. IT WILL REMAIN DRY THROUGH THE NIGHT. LOWS WILL
RANGE FROM THE UPPER 30S IN THE FAR NORTHEAST NEAR HARRISON
TONIGHT TO THE LOW 50S IN THE SOUTHWEST NEAR SOUTH HAVEN.
DISCUSSION
ISSUED AT 308 PM EDT MON MAY 6 2024
- POTENTIAL FOR STRONG/SEVERE STORMS TUESDAY
SEVERE STORMS ARE JUST DEVELOPING OVER THE PLAINS IN RESPONSE TO
STRONG DYNAMICS BEING PRODUCED BY LOW PRESSURE OVER THE NORTHERN
PLAINS ALONG A WARM/OCCLUDED FRONTAL BAND. THESE STORMS...IN
WEAKENING MODE...WILL MOVE EAST TONIGHT AND MOVE TOWARD LOWER MI
TUESDAY MORNING. THESE STORMS WILL BE WEAKENING AS THEY MOVE
ACROSS THE CWA TUESDAY MORNING DUE TO DRIER AIR AND LIMITED
INSTABILITY.
ONCE THE INITIAL SHOWERS/STORMS MOVE ACROSS BY LATE MORNING,
WE'LL LIKELY SEE A LULL OF A COUPLE OF HOURS AND WITH MORE STORM
REDEVELOPMENT DURING THE MID AFTERNOON. CAPE VALUES INCREASE
DRAMATICALLY BEHIND THE FRONTAL BOUNDARY AND WILL BE HELPED OUT
BY ANY CLEARING THAT WE SEE. AN APPROACHING STRONG SHORT WAVE
THAT'S EJECTED OUT OF THE PLAINS UPPER LOW WILL SUPPORT CONVECTIVE
REDEVELOPMENT. DEWPOINTS SURGE INTO THE LOWER 60S BEHIND THE
FRONT. STRONG SHEAR IN THE 55 KT RANGE COUPLED WITH 1K+ J/KG
SBCAPE, 6.5-7 C/KM MID LEVEL LAPSE RATES 40KT LLJ AND A 75KT MID
LEVEL JET WILL SUPPORT ORGANIZATION. IN THIS CASE, THE STRONGEST
DYNAMICS WILL REMAIN SOUTH OF THE CWA, BUT WILL BE STRONG ENOUGH
TO PRODUCE A WIND AND HAIL THREAT FROM ROUGHLY 3PM-8PM. SPC HAS
HIGHLIGHTED A SLIGHT RISK FOR SEVERE STORMS GENERALLY SOUTH OF
I-96 WITH A MARGINAL RISK FOR MOST OF THE REST OF THE CWA. ANY
LINGERING SHOWERS/STORMS SHOULD BE OUT OF THE CWA BY 06Z
WEDNESDAY.
- WET AND COOL WEATHER FOR THE END OF THE WEEK
A POSITIVE TILTED MID LEVEL WAVE WILL BE TRACKING THROUGH THE GREAT
LAKES REGION LATER WEDNESDAY AND INTO THURSDAY. PWATS CLIMB AS THIS
FEATURE TRACKS THROUGH TOPPING AN INCH IN SOUTHERN PARTS OF THE CWA.
THIS IS A GOOD SETUP FOR PERIOD OF STEADY RAIN, WHICH WILL ALSO ACT
TO KEEP THE TEMPERATURES DOWN. THE MODELS DO VARY CONSIDERABLY
WITH THE LOCATION AND AMOUNTS OF RAIN. THE GFS HAS BEEN STEADY IN
SHOWING A SWATH OF HEAVIER RAIN FOR MUSKEGON RIVER BASIN, WHILE THE
ECMWF AND GEM ARE AIMING THE PRECIPITATION FURTHER SOUTH AND TRENDING
FURTHER SOUTH.
ANOTHER MID LEVEL WAVE COMES DOWN FROM THE CANADIAN PRAIRIES ON
FRIDAY NIGHT. THIS WAVE WILL BRING DOWN ANOTHER SURGE OF COOL AIR
AND THERE COULD EVEN BE SOME LAKE EFFECT RAIN SHOWERS WITH THIS
SECOND WAVE. WHILE QPF IS PROJECTED TO BE LIGHT, GIVEN THE
ENHANCEMENT OF THE MOISTURE FROM LAKE MI, WE WILL NUDGE UP THE POPS
FOR FRIDAY NIGHT INTO SATURDAY TO ACCOUNT FOR THIS. WITH 850 MB
TEMPS STRUGGLING TO TOP 0 DEG C, THE DAYTIME TEMPERATURES ARE LIKELY
TO STAY AT LEAST SEVERAL DEGREES BELOW NORMAL FOR BOTH FRIDAY AND
SATURDAY.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 123 AM EDT TUE MAY 7 2024
VFR CONDITIONS WILL PREVAIL THROUGH TUESDAY MORNING THEN MVFR
CONDITIONS COULD DEVELOP BY 18Z WAS A BAND OF SHOWERS MOVES NORTH
INTO LOWER MICHIGAN. STRONG THUNDERSTORMS ARE POSSIBLE BETWEEN
ABOUT 20Z AND 23Z AND THESE STORMS COULD BRING HAIL AND STRONG
GUSTY WINDS. OTHERWISE WINDS WILL BE LIGHT TONIGHT THEN SOUTHEAST
TO SOUTH WINDS AROUND 10 KNOTS COULD GUST TO 20 KNOTS AT TIMES ON
TUESDAY.
MARINE
ISSUED AT 308 PM EDT MON MAY 6 2024
SOUTHEAST WIND GUSTS WILL INCREASE TO AROUND 20 KNOTS TONIGHT
WHICH MAY TOUCH ON ADVISORY CRITERIA FOR A FEW HOURS TUESDAY
MORNING, BUT GIVEN THE OFFSHORE FLOW AND THE SHORT DURATION, WE'LL
HOLD OFF ON A HEADLINE FOR NOW.
THUNDERSTORMS ARE POSSIBLE TUESDAY MORNING AND AGAIN TUESDAY
AFTERNOON, WHICH THE AFTERNOON STORMS BEING POTENTIALLY STRONG TO
SEVERE.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
UPDATE...
DISCUSSION...MJS/04
AVIATION...OSTUNO
MARINE...04
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