487
FXUS63 KGRR 141832
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
232 PM EDT TUE OCT 14 2025
KEY MESSAGES
- VERY LIGHT RAIN TUESDAY NIGHT
- CHANCE OF SHOWERS FRIDAY MORNING WITH A BRIEF WARMUP
- SIGNIFICANT PATTERN CHANGE THIS WEEKEND
DISCUSSION
ISSUED AT 231 PM EDT TUE OCT 14 2025
- VERY LIGHT RAIN TUESDAY NIGHT
LARGE SCALE RIDGING SUPPORTS THE ONGOING DRY CONDITIONS ACROSS THE
AREA THIS AFTERNOON. HOWEVER, A RIDGE RIDING SHORTWAVE WILL CROSS
THE REGION TONIGHT PROVIDING SUFFICIENT FORCING FOR A FEW RAIN
SHOWERS. HOWEVER, THERE IS A NOTABLE LACK OF MOISTURE IN THE LOW-
LEVELS WITH BUFKIT OVERVIEWS SHOWING MOISTURE MAINLY CONCENTRATED IN
THE 700-400 MB LAYER. THIS WILL LEAD TO A MIX OF VIRGA AND VERY
LIGHT SHOWERS, WITH HREF LPMM GUIDANCE SUGGESTING A FEW HUNDREDTHS
OF AN INCH IN ACCUMULATIONS. MORE NOTABLE RAINFALL IS FAVORED WEST
OF THE AREA WHERE BETTER MOISTURE QUALITY WILL BE PRESENT.
- CHANCE OF SHOWERS FRIDAY MORNING WITH A BRIEF WARMUP
CONDITIONS DRY OUT WEDNESDAY MORNING AS THE MID-LEVEL WAVE CLEARS
THE AREA WITH SURFACE AND UPPER-LEVEL RIDGING DOMINATING THE
FORECAST LATER WEDNESDAY INTO THURSDAY.
OUR NEXT CHANCE OF SHOWERS WILL BE FRIDAY MORNING AS A WARM FRONT
CROSSES THE GREAT LAKES. MOISTURE QUALITY IS NOT IDEAL SUPPORTING
POPS IN THE 20-50 PERCENT CHANCE RANGE, HIGHEST ACROSS CENTRAL LOWER
MICHIGAN WHERE THE BETTER MOISTURE RESIDES. BEHIND THIS WARM FRONT,
850MB TEMPS CLIMB INTO THE MID TEENS. THIS WILL BRING HIGHS INTO THE
LOW AND POSSIBLY THE MID 70S BY SATURDAY.
- SIGNIFICANT PATTERN CHANGE THIS WEEKEND
THE PRIMARY FOCUS OVER THE NEXT 7 DAYS WILL BE THE MORE SUBSTANTIAL
SYSTEM THAT ARRIVES FOR THE WEEKEND. THE POTENT TROUGH OFF THE
COAST OF CALIFORNIA WILL EJECT TO THE NORTHEAST AND PHASE WITH A
NORTHERN STREAM WAVE. THE RESULTING LONGWAVE TROUGH REPLACES THE
RIDGE AND WILL FEATURE SEVERAL EMBEDDED SHORTWAVES. RAIN ARRIVES
FRIDAY NIGHT INTO SATURDAY AS A COLD FRONT ACCOMPANIES ONE OF
THESE WAVES, WITH FORECAST MUCAPE WARRANTING A MENTION OF THUNDER.
SHOWERS WILL CONTINUE INTO SUNDAY AS THE TROUGH PERSISTS
OVERHEAD.
HOWEVER, UNCERTAINTY REMAINS WITHIN THE ENSEMBLES AS TO THE SPECIFIC
EVOLUTION OF THE TROUGH INCLUDING THE POTENTIAL FOR SECONDARY
CYCLOGENESIS OVER THE GREAT LAKES REGION. THIS WOULD AFFECT WINDS AS
WELL AS RAINFALL POTENTIAL. THE GFS SET OF SOLUTIONS IS ALSO NOTABLY
SLOWER IN CLEARING THE TROUGH THAN THE ECMWF SET, WHICH WOULD KEEP
RAIN SHOWERS INTO MONDAY AS WELL. REGARDLESS, MUCH COLDER AIR
ARRIVES WITH THE TROUGH AND COLD FRONTAL PASSAGE. HIGHS WILL FALL
INTO THE 50S AS 850MB TEMPS FALL TO NEAR 0C.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 115 PM EDT TUE OCT 14 2025
SCATTERED TO BROKEN CUMULUS CLOUD BASES AROUND 2,500 FEET WILL
AFFECT LAN, AZO, BTL, AND JXN FOR A FEW HOURS THIS AFTERNOON, THEN
THIS EVENING IS LIKELY TO BE VFR WITH HIGH CLOUDS STREAMING IN.
TONIGHT, CEILINGS WILL LOWER FROM 15,000 FEET TO 6,000 FEET BY
MORNING. AREAS OF LIGHT RAIN WILL BE PRODUCED FROM THESE CLOUDS,
BUT WILL BE PARTIALLY EVAPORATING INTO DRIER AIR ON THE WAY TO THE
GROUND. LIGHT RAIN MAY REACH THE GROUND ONCE IN A WHILE, AND
VISIBILITY IS NOT EXPECTED TO BE MUCH AFFECTED.
MARINE
ISSUED AT 115 PM EDT TUE OCT 14 2025
NORTH WINDS 15 TO 20 KNOTS ARE EXPECTED TO BUILD 2 TO 4 FT WAVES
FROM THE SABLE POINTS THIS AFTERNOON DOWN THE SHORE TOWARD SOUTH
HAVEN AND ST JOSEPH BY LATE THIS EVENING. WINDS WILL BECOME MORE
FROM THE NORTHEAST TONIGHT AND KEEP THE LARGER WAVES OVER THE OPEN
WATERS. WED AND THU ARE EXPECTED TO HAVE SOME 1 TO 2 FT WAVES.
SMALL CRAFT ADVISORY CONDITIONS ARE LIKELY STARTING EARLY FRIDAY
AND CONTINUING THROUGH THE WEEKEND.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...THOMAS
AVIATION...CAS
MARINE...CAS
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