539 
FXUS63 KGRR 071142
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
742 AM EDT Fri Oct 7 2022

LATEST UPDATE...
Aviation

.DISCUSSION...(Today through next Thursday)
Issued at 333 AM EDT Fri Oct 7 2022

-- Frost/freeze potential tonight --

The main challenge today will be demarcating frost advisory 
and/or freeze warning areas. It won't be a great setup in all 
areas, as the center of the surface high will be well WSW of the 
Great Lakes, turning low-level winds more from the west and 
nudging lake-effect clouds inland late in the night. So it's a 
good bet the lakeshore counties can be excluded from frost 
concerns. Moderate confidence that diurnal cumulus or 
stratocumulus will dissipate within a few hours after sunset 
inland as ridging and subsidence work to dry out that layer. Once 
that occurs the surface layer should decouple pretty quickly and 
winds will become light. With highs about 15 degrees below normal 
today, temperatures won't have far to fall to get into freeze 
territory. The longer cloud-free time window and thus colder 
temperatures are favored around the Capital region and south. 
Note, frost/freeze headlines in the US-10 counties (Ludington to 
Clare) and north have ended for the season.

-- Milder air returns for the first half of next week --

The ensembles of the ECMWF, GFS, and Canadian are all exhibiting 
pretty low spread in the temperature and precipitation solutions 
through Wednesday as the wave pattern across the continent becomes
more progressive and translates eastward. This would take the 
milder air built up within the western ridge and advect it toward 
us, recovering our temperatures back into the mid/upper 60s 
Tue/Wed. Then the next digging upper level trough and surface cold
front arriving between Wed/Thu would provide us with our next 
chance of appreciable rain.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 742 AM EDT Fri Oct 7 2022

Numerous MVFR cigs early this morning, lifting toward mostly VFR 
levels by afternoon as north winds of 10 to 20 kts continue. Winds
diminishing after 00Z to less than 10 kts with scattered to 
broken clouds around 4000 ft lingering. 

&&

.MARINE...
Issued at 207 AM EDT Fri Oct 7 2022

As the peak wind speeds are trending down a bit and and any
remaining gales are expected to remain over the open waters for a
few more hours, the gale warning in our nearshore is replaced 
with a small craft advisory. We have also extended the small craft
advisory into Sunday morning. Winds will be from the north today 
and from the west on Saturday. The winds from the north will
protect areas between Whitehall and Holland from the larger 
waves, but the winds alone still support the advisory for at least
part of the day. We do expect a bit of a lull in the winds and
waves Friday night but it wouldn't be long enough to justify
expiring the advisory only to have to reissue another one.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory from 2 AM to 9 AM EDT Saturday for MIZ044>046-051-
     052-057>059-065-072.

     Freeze Watch from late tonight through Saturday morning for 
     MIZ066-067-073-074.

LM...Small Craft Advisory until 11 AM EDT Sunday for LMZ844>849.

&&

$$

DISCUSSION...CAS
AVIATION...Meade
MARINE...CAS