203
FXUS63 KGRR 021701
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
101 PM EDT THU JUL 2 2026
KEY MESSAGES
- CONVECTIVE TRENDS REMAIN THE MAIN FORECAST CONCERN
- HEAT CONTINUES INTO THE HOLIDAY WEEKEND
DISCUSSION
ISSUED AT 412 AM EDT THU JUL 2 2026
- CONVECTIVE TRENDS REMAIN THE MAIN FORECAST CONCERN
A QUASI-STATIONARY FRONT DROVE CONVECTION UPSTREAM YESTERDAY
EVENING AND INTO THE OVERNIGHT HOURS. THIS ACTIVITY MOVED INTO
FAR NORTHERN SECTIONS OF THE FORECAST AREA YESTERDAY EVENING AND
INTO TONIGHT. FOR OUR AREA WE REMAIN ON THE WARM SIDE OF THE
BOUNDARY WITH AROUND 2,000 J/KG OF MUCAPE AT 400AM. CONFIDENCE IN
STORM MORPHOLOGY REMAINS ON THE LOWER SIDE OVERALL. A STRONG LOW
LEVEL JET IS IN PLACE OVERHEAD THIS MORNING WHICH IS USUALLY A
DRIVER OF ADDITIONAL STORMS. THE SPC HREF DOES INDICATE A ROUND OF
CONVECTION DURING THE MORNING AND INTO THE MIDDAY HOURS BETWEEN
ROUGHLY 10AM AND 2PM. WE ARE IN A MARGINAL TO SLIGHT RISK FOR
SEVERE WEATHER TODAY VIA THE SPC AND THIS IS LARGELY TIED TO THE
LEVEL OF INSTABILITY THAT WILL BE IN PLACE. SOME STRONGER WINDS IN
THE PROFILE WILL MAKE DAMAGING WINDS THE MAIN THREAT. ANOTHER
ROUND OF STORMS IS EXPECTED THIS EVENING. HEAVY RAIN IS ALSO VERY
POSSIBLE TODAY WITH HIGH PWAT AIR IN PLACE AND A BOUNDARY TO FOCUS
THE STORMS.
WE REMAIN IN A THREAT FOR SEVERE WEATHER BOTH FRIDAY AND SATURDAY WITH
THE SPC HAVING US IN A MARGINAL THREAT BOTH DAYS. CONVECTION WILL
BE DRIVEN BY A STATIONARY FRONT REMAINING IN THE AREA AND MID
LEVEL MCV'S FLOATING THROUGH THE REGION TO ENHANCE THE THREAT.
AGAIN, CONFIDENCE IS ON THE LOWER SIDE WITH REGARD TO HOW STORMS
EVOLVE EACH DAY. HEAVY RAIN WILL REMAIN A THREAT ON FRIDAY AND
SATURDAY AS THE AIRMASS WILL LARGELY REMAIN THE SAME.
- HEAT CONTINUES INTO THE HOLIDAY WEEKEND
GFS MOS NUMBERS LOOK MORE REASONABLE WHICH KEEPS TEMPERATURES IN
THE 90S TODAY, FRIDAY AND SATURDAY (OR AT LEAST NEAR 90). WE
"COOL" BACK INTO THE 80S FOR HIGHS ON SUNDAY AND INTO EARLY NEXT
WEEK. WILL MAINTAIN THE CURRENT HEAT WARNING AS IS, BUT WE MAY
NEED TO EXTEND IT INTO FRIDAY AT LEAST.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 100 PM EDT THU JUL 2 2026
THE NEXT SIX HOURS WILL FEATURE VFR CONDITIONS AS DAYTIME CU
DEVELOP IN THE 3-4KFT RANGE, WITH BKN CIGS POSSIBLE AT JXN/BTL.
AFTER 00Z, ATTENTION TURNS TO CONVECTIVE POTENTIAL HOWEVER
CONFIDENCE IS LOW IN HOW CONVECTIVE DEVELOPMENT EVOLVES AND SHORT
RANGE MODEL GUIDANCE REALLY STRUGGLES ON COVERAGE AND PLACEMENT SO
HAVE MAINTAINED PROB30S FOR TSRA. THERE HAS BEEN A BIT OF A LATER
TREND IN THUNDERSTORM TIMING WITH 02-10Z AS THE FAVORED WINDOW
BASED ON HRRR/RRFS/REFS/FV3 GUIDANCE. MVFR AND LOWER CONDITIONS
AND GUSTS IN EXCESS OF 40 KNOTS ARE POSSIBLE IN ANY CONVECTION
THAT DEVELOPS. LOOK FOR GUSTY WINDS TO AROUND 25 KNOTS THIS
AFTERNOON DIMINISHING TONIGHT.
MARINE
ISSUED AT 412 AM EDT THU JUL 2 2026
WE WERE PREVIOUSLY THINKING THAT WINDS AND WAVES WOULD BE NEAR
ADVISORY CRITERIA LEVELS AT THIS TIME, BUT THAT HAS NOT PANNED
OUT EARLY THIS MORNING. WINDS ARE WELL BELOW CRITERIA AT THIS
POINT WITH MANY SITES FALLING BELOW 10 KNOTS. BUOYS AT PRESENT ARE
INDICATING 1 FOOT WAVES. SO, NO NEED TO ISSUE ANY HEADLINES THIS
MORNING GIVEN CURRENT CONDITIONS AND WHAT THE REST OF TODAY AND
TONIGHT LOOK LIKE. WE MAY SEE CONDITIONS COME UP TO A MODERATE
SWIM RISK TODAY, OTHERWISE WE ARE HEADING INTO A LIGHTER WIND
REGIME AS WE MOVE INTO AND THROUGH THE HOLIDAY WEEKEND.
GRR WATCHES/WARNINGS/ADVISORIES
MI...EXTREME HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR MIZ037>040-
043>046-050>052-056>059-064>067-071>074.
HEAT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT FRIDAY FOR
MIZ046-051-052-056>059-064>067-071>074.
MARINE...NONE.
DISCUSSION...DUKE
AVIATION...THOMAS
MARINE...DUKE
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