624
FXUS63 KGRR 062320
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
720 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 /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 719 PM EDT Sun Jul 6 2025


The cold front continues to move eastward taking the remaining
showers and storm with it. Cooler, air behind the front will
continue to bring northwesterly flow across the region. Along
with this will be lowering cigs. MKG and BIV has already had IFR
cigs. Expect IFR ceilings to overspread the region this evening
and continue through tomorrow morning through the eastern TAF
sites. IFR will build in from the Northeast, as northerly flow
meets and stalls with upper level moisture advecting into
southern lower Michigan. There is some question on timing but IFR
cigs could for as early 04Z. Most TAFs will see it between 06Z to
09Z. Cigs will slowly retreat from the Northwest to Southeast,
exiting JXN between 15Z to 18Z.


&&

.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