387
FXUS63 KGRR 260739
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
339 AM EDT THU JUN 26 2025
KEY MESSAGES
- RAIN AND THUNDERSTORMS TODAY THROUGH FRIDAY
- HOT AND HUMID CONDITIONS CONTINUE
DISCUSSION
ISSUED AT 339 AM EDT THU JUN 26 2025
- RAIN AND THUNDERSTORMS TODAY THROUGH FRIDAY
WARM AIR ADVECTION, MUCAPE VALUES OF 500-1000J/KG, AND A POCKET OF
HIGHER 850MB MOISTURE IS SPARKING OFF SCATTERED SHOWERS AND
THUNDERSTORMS THIS MORNING ALONG WITH THE LOW LEVEL JET AND THE
REMNANT BOUNDARY FROM THE STORMS FROM WISCONSIN.
WITH THE MOISTURE AND INSTABILITY IN PLACE THROUGHOUT THE DAY AS
THE WARM FRONT SHIFTS NORTH SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED. THIS AFTERNOON THE BETTER CHANCES WILL BE FOCUSED
EAST OF US-131 WITH THE POTENTIAL FOR SOME STRONG TO SEVERE
STORMS. WINDS WILL BE THE PRIMARY CONCERN BUT CAN'T RULE OUT THE
POTENTIAL FOR SOME SMALL HAIL.
A LULL IS POSSIBLE TONIGHT BUT WE'LL HAVE TO MONITOR THE
CONVECTION MOVING OUT OF WISCONSIN WITH THE SHORTWAVE TROUGH.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT AS IT MOVES
THROUGH FRIDAY, AREAS SOUTH AND EAST OF GRAND RAPIDS HAVE THE BEST
CHANCE WITH INSTABILITY BUILDING THROUGHOUT THE DAY. HREF MEAN
SBCAPE VALUES ARE AROUND 2000 J/KG WITH AROUND 25 KNOTS OF SHEAR.
WHILE THE SHEAR ISN'T GREAT, THERE STILL IS THE POTENTIAL FOR
STRONGER STORMS, ESPECIALLY THE FARTHER EAST YOU GO. AGAIN WINDS
ARE THE PRIMARY CONCERN WITH ANY STRONGER STORM.
WITHIN THIS MOIST ENVIRONMENT, HEAVY RAINFALL IS LIKELY WITH ANY
SHOWER OR THUNDERSTORM (RATES AROUND 1 INCH PER HOUR).
THUNDERSTORMS THAT TRACK REPEATEDLY OVER THE SAME AREA COULD
CAUSE MINOR FLOODING ESPECIALLY IN URBAN AREAS AND KNOWN TROUBLE
SPOTS.
DRY CONDITIONS RETURN FRIDAY NIGHT AND CONTINUE THROUGH MOST OF
THE WEEKEND. THE ARRIVAL OF A LONGWAVE TROUGH AND A PARADE OF
EMBEDDED SHORTWAVES WILL BRING THE POTENTIAL FOR SHOWERS AND STORMS
BACK LATER SUNDAY INTO THE WORK WEEK NEXT WEEK.
- HOT AND HUMID CONDITIONS CONTINUE
DEW POINTS WILL CONTINUE TO BE IN THE 60S AND 70S THROUGH THE
WEEKEND AND EVEN INTO NEXT WEEK. WITH HIGHS MAINLY IN THE 80S,
HEAT INDICES WILL BE IN THE 90S MORE DAYS THAN NOT THROUGH THE
WEEKEND (SATURDAY LOOKS TO REMAIN IN THE 80S). AT THIS TIME NOT
EXPECTING VALUES TO REACH 100 OR MORE, BUT STILL TAKE CARE BY
STAYING HYDRATED AND LIMITING TIME OUTSIDE.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 157 AM EDT THU JUN 26 2025
MONITORING SHOWERS THAT HAVE DEVELOPED OVER LAKE MICHIGAN. AT THIS
TIME CONFIDENCE IS NOT HIGH THAT THEY'LL IMPACT ANY OF THE TAF
SITES.
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP THIS MORNING WITH THE FRONTAL BOUNDARY LINGERING OVER THE
AREA. BEST CHANCES WILL BE TOWARD AZO, BTL, JXN, AND LAN THROUGH
THE DAY, BUT MKG AND GRR STILL HAVE A CHANCE DURING THE MORNING
HOURS. THEREFORE HAVE ADDED PROB30 GROUPS TO ALL TAF SITES.
AFTERNOON STORMS COULD BE STRONG AND PRODUCE GUSTY WINDS. HEAVY
RAINFALL IS POSSIBLE WITH ANY SHOWER AND THUNDERSTORM ALONG WITH
MVFR CEILINGS AND IFR VISIBILITIES. AS SEEN OVER THE PAST FEW
DAYS, 1 INCH PER HOUR RAINFALL RATES ARE POSSIBLE.
WITH THE MOISTURE IN PLACE WE WILL HAVE TO MONITOR THE POTENTIAL
FOR FOG TO DEVELOP. JXN IS ALREADY REPORTING SOME IFR CLOUDS,
THEREFORE HAVE ADDED A BRIEF PERIOD OF REDUCED VISIBILITIES AND
LOW CEILINGS TO THE TAF.
MARINE
ISSUED AT 339 AM EDT THU JUN 26 2025
PERIODS OF RAIN AND THUNDERSTORMS ARE EXPECTED THROUGH FRIDAY
BEFORE DRY CONDITIONS RETURN THIS WEEKEND. LIGHTNING WITH THE
POTENTIAL FOR HIGHER WINDS AND WAVES WILL CREATE HAZARDOUS
CONDITIONS FOR MARINERS AND BEACHGOERS.
OTHERWISE THE CURRENT WAVE AND WIND FORECAST REMAINS BELOW SMALL
CRAFT ADVISORY AND BEACH HAZARD STATEMENT CRITERIA THROUGH THE
WEEKEND.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...RAH/THOMAS
AVIATION...RAH
MARINE...RAH
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