591 
FXUS63 KGRR 060728
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
328 AM EDT Mon Sep 6 2021

LATEST UPDATE...
Synopsis/Discussion/Aviation/Marine

.SYNOPSIS...
Issued at 328 AM EDT Mon Sep 6 2021

- Upper troughing with severe weather possible Tuesday

&&

.DISCUSSION...(Today through next Sunday)
Issued at 328 AM EDT Mon Sep 6 2021

After a fair weather Labor Day, we look to the risk of severe 
weather on Tuesday as an upper trough amplifies across the central
Great Lakes with wind profiles show 40 knots of shear. Strong 
unidirectional shear suggests storm type will favor linear, 
bowing segments. Any deep convection will be capable of wind
damagegiven 50 knots progged to be in the lowest 5 kft AGL. Dry 
adiabatic subcloud layer will enhance downburst potential.

Timing looks to be from mid-afternoon across the northwest
forecast area to mid-evening by the time the storms clear the 
southeast sections near Jackson County. Synoptic wind gusts in the
cold advection behind the storms could also gust over 40 mph. The
storms could also build deep enough to produce large hail with
forecast soundings showing CAPE through the minus 10C to minus 30C
zone. The storms will be moving quickly so even in heavy rain 
rates materialize, flooding should be mitigated by storm speed.

Fair and cool weather follows for Wednesday through Friday with
overnight lows in the 40s in most places by Thursday morning and
even some 30s are possible in the cold spots.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 328 AM EDT Mon Sep 6 2021

VFR conditions expected through tonight with west to northwest
winds 5 to 10 knots.

&&

.MARINE...
Issued at 300 AM EDT Mon Sep 6 2021

Winds and waves will decrease this morning and we expect to let
the Small Craft and Beach Hazards Statement expire at 8 am. Winds
and waves will increase again on Tuesday and severe thunderstorms
are possible in the afternoon. Conditions will remain hazardous
through Wednesday as strong winds and high waves continue.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 8 AM EDT this morning for MIZ037-
     043-050-056-064-071.

LM...Small Craft Advisory until 8 AM EDT this morning for LMZ844>849.

&&

$$

SYNOPSIS...Ostuno
DISCUSSION...Ostuno
AVIATION...Ostuno
MARINE...Ostuno