400
FXUS63 KGRR 150833
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
333 AM EST Fri Nov 15 2024

.KEY MESSAGES...

- Lingering Low Clouds

- Weak cold front swings through Sunday and Sunday night

- More active pattern sets up from the middle of next week

&&

.DISCUSSION...
Issued at 333 AM EST Fri Nov 15 2024

- Lingering Low Clouds

Extensive stratus blankets several states east of the Mississippi
River early this morning, which is approximately where the sfc
ridge axis is located. Even where skies are currently clear
across MN/IA/MO there are more low clouds and fog forming/filling
back in west of the main area of stratus.

A cloudy forecast looks to be the way to go today since we remain
east of the sfc ridge axis and models keep the low level moisture
locked in under the subsidence inversion. If any breaks in the
clouds manage to form tonight we should just see those pockets
fill back in with stratus or fog due to a lack of wind under the
sfc high.

Low clouds and areas of fog expected to linger into the first
half of Saturday then should begin to scour out Saturday afternoon
with the passage of the sfc ridge to the east. Increasing
southeast winds on the back side of the ridge leads to a better
likelihood of mixing some drier air down to the sfc. However high
clouds will be spilling in from the west so overall prospects for
sunshine appear limited Saturday.

- Weak cold front swings through Sunday and Sunday night

A weak cold front is still forecast by the consensus of models to
move into the area on Sunday and stall across Southern Lower
Michigan Sunday night. The front will be moisture limited and as
such will not produce much in the way of precipitation. If fact, WPC
is producing no precipitation across the Southwest Quarter of Lower
Michigan. We still feel with the upper shortwave nearby to the north
on Sunday and a trough moving through Sunday night, some light pops
are warranted. We have 20-30 pct pops in the forecast for these
periods for the most part. The moisture is a bit disjointed in the
low levels with much of the 5,000-10,000 foot layer dry. So, this
may be more of a drizzle event or a very light rain.

- More active pattern sets up from the middle of next week

The focus of the longer term portion of the 7 day forecast is
squarely on the middle of next week. This reason for this is a bit
of a pattern change. The evolution of the pattern is starting to
converge on a solution where both the GFS and ECMWF ensemble means
are indicating a shortwave lifting out of the desert southwest
lifting north into the plains and phasing with an upper trough
moving out of the Rockies. This evolution occurs on Monday and
Tuesday off to our west with an upper low then moving through the
Great Lakes on Wednesday and Thursday.

As for the details we will be on the east side of the system on
Monday and Tuesday so any precipitation will be rain. The upper low
almost traverses directly overhead on Wednesday and Thursday
bringing addition chances for rain. The GFS has slightly colder air
in place for Wednesday night into Thursday night, but essentially
just on the threshold for lake effect snow. At this point our going
forecast is for all rain through Thursday given the coldest air with
the upper low pivots by to our south. The middle of next week looks
to be cloudy with occasional rain showers.


&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1245 AM EST Fri Nov 15 2024

IFR to LIFR cigs/vsbys in stratus and fog continuing overnight.
Areas of fog gradually lifting Friday morning with cigs trending
MVFR for most of the area by 18Z Friday but likely remaining OVC.

&&

.MARINE...
Issued at 333 AM EST Fri Nov 15 2024

Surface ridging will keep winds and waves on the low side through
Saturday morning then winds increase out of the southeast
Saturday afternoon. Our next risk of hazardous winds and waves is
Saturday night into Sunday when a period of strong southerly winds
is expected ahead of an approaching cold front. Winds veer
southwest Sunday then west Sunday night with the passage of that
front, then hazardous conditions gradually subsiding late Sunday
night.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

DISCUSSION...Meade/Duke
AVIATION...Meade
MARINE...Meade