953
FXUS63 KGRR 061847
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
247 PM EDT Sun Jul 6 2025

.KEY MESSAGES...

- Showers and thunderstorms ahead and along a cold front through
  tonight with a low chance of severe weather into this evening

- Next chance for rain is Wednesday

&&

.DISCUSSION...
Issued at 247 PM EDT Sun Jul 6 2025

- Showers and thunderstorms ahead and along a cold front through
  tonight with a low chance of severe weather into this evening

Instability and shear remain marginal this afternoon and storms
have not shown much in terms of organization yet, but continued
sfc heating across the SE zones will increase chances for some
heftier updrafts there through the early evening. Main threat
will be strong downdrafts associated with descending precip cores
in pulse storms, although these will be isolated if they occur.

Severe threat diminishes after sunset with some showers persisting
along the slow moving front overnight into Monday morning across
the southeast forecast area.

- Next chance for rain is Wednesday

Sfc high builds in for Tuesday into early Wednesday then weak
moisture return sets up ahead of a shortwave trough and cold front
with another chance for scattered convection Wednesday, primarily
from late morning through afternoon. Once again, deep layer shear
and instability are marginal, but isolated pulse storm downbursts
are possible.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 205 PM EDT Sun Jul 6 2025

Storms have begun to form with scattered showers and storms
expected to temporary drop vsbys and cigs to IFR from 18Z to 00Z.
 Expect scattered convection between 18 to 22Z with more organized
storms as the front moves through between 20Z to 00Z. There is
still some question on timing, hence the overlap in times above.
TAF sites that could see the lines of storms will be LAN, BTL, AZO
and JXN. However if it forms further west AZO and GRR could see
another round of storms late this afternoon. Have adjusted this in
the TAFS.

The cold front should exit shortly after 00Z with some
clearing in its wake. Ceilings will deteriorate throughout the
night and any areas that received heavy rain could see some patchy
fog. Expect IFR cigs and possibly vsbys overnight between 05Z to
14Z at LAN, JXN, BTL. MVFR cigs with periods of IFR are possible
at GRR and AZO. MKG could see some showers between 18Z to 22Z but
to a lesser extent in relation to the other TAF sites. Any
reducing cigs and vsbys overnight will slowly improve Monday
between 14Z to 17Z west to east.

&&

.MARINE...
Issued at 247 PM EDT Sun Jul 6 2025

Cold front moving down the coast this afternoon with north winds
gusting around 20 knots at Ludington. Waves appear to be mainly in
the 2 to 3 foot range and winds are below 20 knots this afternoon
but we will keep the Beach Hazards Statement and Small Craft
advisory going since there is still the possibility of 4 foot
waves and gusts to 25 knots this evening.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 11 PM EDT this evening for MIZ037-
     043-050-056.
MARINE...Small Craft Advisory until 11 PM EDT this evening for LMZ846>849.

&&

$$

DISCUSSION...Ostuno
AVIATION...Ceru
MARINE...Ostuno