464
FXUS63 KGRR 072358
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
758 PM EDT SAT JUN 7 2025
KEY MESSAGES
- SHOWERS TONIGHT SOUTH; SHOWERS/STORMS SUNDAY P.M.
- QUIET AND MILD MID-WEEK
- POTENTIALLY UNSETTLED WEATHER LATE WEEK
DISCUSSION
ISSUED AT 248 PM EDT SAT JUN 7 2025
- SHOWERS TONIGHT SOUTH; SHOWERS/STORMS SUNDAY P.M.
THANKFULLY THE AREA HAS EXPERIENCED MUCH LESS SMOKE TODAY THAN THE
PREVIOUS DAYS. SKIES HAVE BEEN TRULY MOSTLY SUNNY WITH JUST SOME
HIGH LEVEL CIRRUS SPREADING IN FROM THE SOUTH THIS AFTERNOON.
OUR FIRST FOCUS OF THE FORECAST IS ON AN UPPER SHORT WAVE THAT IS
CURRENTLY OVER IA AND MO THIS AFTERNOON, CAUSING SOME SHOWERS AND A
FEW STORMS OUT THERE CURRENTLY. THE CENTER OF THIS WAVE IS POISED TO
MOVE ACROSS NORTHERN INDIANA TONIGHT AND THROUGH SE MICHIGAN EARLY
SUNDAY MORNING.
WE WILL BE REMAINING ON THE COOL SIDE OF THIS SYSTEM BEING NORTH OF
THE WAVE. THE FLOW FROM THE EAST IS VERY INDICATIVE OF THE AREA
STAYING IN THE COOLER AREA OF THIS SYSTEM. THESE SHOULD BE MAINLY
SHOWERS STAYING SOUTH OF THE I-96 CORRIDOR TONIGHT. INSTABILITY
PROGS SHOW VERY LITTLE IF ANY INSTABILITY TO BE HAD FOR TONIGHT.
WE WILL SEE A BREAK IN THE RAIN CHANCES FROM AROUND DAYBREAK SUNDAY
THROUGH MID-AFTERNOON. BEGINNING LATE SUNDAY AFTERNOON THROUGH
SUNDAY EVENING, SOME SHOWERS AND EVEN A RUMBLE OF THUNDER WILL
BECOME POSSIBLE AS A BETTER PIECE OF UPPER ENERGY IN THE FORM OF AN
UPPER LOW WILL APPROACH THE AREA LATE.
EVEN THOUGH THERE ARE THUNDER CHANCES WITH THIS FRONT THAT WILL BE
MOVING THROUGH, THE POTENTIAL FOR STRONG TO SEVERE STORMS LOOKS
QUITE LIMITED. FIRST, EVEN COMING THROUGH DURING THE LATE AFTERNOON
HOURS, INSTABILITY STAYS BELOW A FEW HUNDRED J/KG. THIS IS THE
RESULT OF DEW POINTS STAYING IN THE LOWER 50S, AND SOME SEMBLANCE OF
A WEAK CAP ALOFT LIMITING UPDRAFTS. DEEP LAYER SHEAR LOOKS TO BE
SUFFICIENT FOR SOME ORGANIZATION WITH VALUES IN THE 30S. HOWEVER THE
LIMITED INSTABILITY REALLY LOOKS TO LIMIT THE THREAT. INSTABILITY
DOES LOOK TO PEAK OVER THE EASTERN PORTIONS OF THE STATE WITH BETTER
LOW LEVEL MOISTURE WITH SFC DEW POINTS IN THE MID TO UPPER 50S.
ONCE THE FRONT MOVES THROUGH ON SUNDAY NIGHT, WE WILL MAINTAIN A
CHANCE OF RAIN SHOWERS INTO MONDAY NIGHT AS THE UPPER LOW ROTATES
OVER THE REGION. THESE WILL BE MAINLY DIURNAL INSTABILITY RAIN
SHOWERS, SCATTERED AROUND.
- QUIET AND MILD MID-WEEK
THE UPPER LOW WILL MOVE OUT MOSTLY BY TUESDAY AFTERNOON, EXCEPT FOR
ONE LINGERING SHORT WAVE THAT ZIPS IN ON THE BACKSIDE OF THE LOW ON
TUESDAY. THIS SHORT WAVE MAY BE JUST ENOUGH COMING IN DURING PEAK
HEATING TO FIRE OFF A SHOWER OR STORM.
ONCE THAT SHORT WAVE MOVES THROUGH TUESDAY NIGHT, WE WILL SEE
QUIETER WEATHER SETTLE IN FOR AT LEAST WEDNESDAY. THIS IS THE RESULT
OF ANTI-CYCLONIC FLOW BUILDING OVER THE AREA WITH A WESTERN U.S.
COAST TROUGH COMING ONSHORE. THE BUILDING RIDGE WILL HELP WARM
TEMPERATURES AS MID TEENS C AT 850 MB MOVES IN.
- POTENTIALLY UNSETTLED WEATHER LATE WEEK
A WEAKER COLD FRONT WILL PASS THROUGH ON WEDNESDAY. THE FIRST THING
THIS FRONT WILL TRY TO DO IS TO COOL TEMPERATURES OFF SOME. THIS
FRONT WILL NOT HAVE MOISTURE WITH IT, AND WON'T BE MUCH OF A PLAYER,
INITIALLY.
WHAT THIS FRONT WILL DO IS BECOME NEARLY STATIONARY JUST SOUTH OF
THE SOUTHERN CWA BORDER AS IT LINES UP TO THE UPPER JET. THIS WILL
SET THE STAGE FOR A POTENTIALLY UNSETTLED PERIOD FOR LATE IN THE
PERIOD WITH POSSIBLE ROUNDS OF SHOWERS AND STORMS RIDING ALONG THE
FRONT.
NOW, THE EXACT DETAILS OF THE FRONT WILL BE TOUGH TO POINT OUT. THEN
IT WILL BE TOUGH TO TRY TO PIN POINT TIMES AND LOCATIONS OF THE
SHORT WAVES THAT RIDE ALONG THE FRONT. THE THREAT WILL BE THERE, SO
SMALLER POPS ARE JUSTIFIED FOR THE LATTER HALF OF THE FORECAST
PERIOD.
WHAT THE FRONT WILL DO IS SETTLE IN
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 754 PM EDT SAT JUN 7 2025
VFR CONDITIONS WILL CONTINUE FOR THE FIRST HALF OF THE TAF
PERIOD. SOME HAZE HAS BROUGHT MVFR VSBYS TO AZO AND THAT WILL
SUBSIDE AFTER SUNSET.
A WEATHER SYSTEM MOVING IN EARLY TOMORROW WILL BRING A CHANCE FOR
LIGHT SHOWERS TO THE SOUTHERN TAF SITES AFTER 05Z. MVFR CIGS AND
VSBYS WILL BE POSSIBLE BETWEEN 10Z TO 14Z. AS THE SHOWERS MOVE
NORTHWARD THAT WILL INCLUDE LAN AND GRR AS WELL. THOSE SHOWERS
WILL MOVE EASTWARD BY 15Z.
A COLD FRONT WILL THEN MOVE THROUGH LATE IN THE DAY WITH SHOWERS
PASSABLE AFTER 21Z AT MKG AND ARRIVING IN THE GRR TO LAN BETWEEN
22 AND 00Z. SOME STORMS COULD BE POSSIBLE WITH THE FRONT.
MARINE
ISSUED AT 248 PM EDT SAT JUN 7 2025
NO HEADLINES EXPECTED AT LEAST THROUGH SUNDAY, WITH POSSIBLE SMALL
CRAFT ADVISORIES SUNDAY NIGHT INTO MONDAY NIGHT. HIGH PRESSURE AT
THE SFC THIS AFTERNOON CENTERED OVER NORTHERN AND NORTHEAST MICHIGAN
WILL SLOWLY MOVE OUT OF THE AREA THROUGH SUNDAY. THE GRADIENT ON THE
BACKSIDE OF THE HIGH IS NOT QUITE STRONG ENOUGH TO NEED AND MARINE
HEADLINES THROUGH SUNDAY, AND WILL BE OFFSHORE IN NATURE THE
MAJORITY OF THIS TIME.
WINDS WILL INCREASE AND BECOME ONSHORE LATE SUNDAY OUT AHEAD OF THE
INCOMING FRONT. THE WINDS WILL BECOME FROM THE WEST/NORTHWEST SUNDAY
NIGHT AND COULD INCREASE ENOUGH TO REQUIRE A HEADLINE FOR THAT TIME.
THAT WILL LINGER INTO MONDAY BEFORE DIMINISHING.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...NJJ
AVIATION...CERU
MARINE...NJJ
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