384
FXUS63 KGRR 261144
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
744 AM EDT Thu Sep 26 2024

.KEY MESSAGES...

- Dry through Friday

- Chances for rain showers this weekend

- Warmer than normal through Tuesday then cooler

&&

.DISCUSSION...
Issued at 350 AM EDT Thu Sep 26 2024

- Dry through Friday

High pressure holds over the region through Friday leading to quiet
weather. Patchy fog is the primary concern early this morning with
sites such as Holland reporting visibilities down to 1/4 mile.
Other sites like Ludington are at 3/4 mile, and Kalamazoo to 2
miles. Fog should stay limited to mainly west of US-131. Once fog
dissipates shortly after sunrise, expect a mostly sunny day with
highs in the mid 70s.

- Chances for rain showers this weekend

No significant changes from last night`s thinking with regard to the
system off to our south this weekend. Helene will make a move into
the Ohio Valley and get caught up with the upper low that will
already be there. Moisture and even wind will be on the increase
across our area in the Friday night through Sunday time frame. We
have chance pops in the forecast for the small chances for rain,
mainly near and south of I-96. QPF amounts look low on the order of
a quarter of an inch or less over the multiple forecast periods that
the Ohio Valley system will affect us.

Sunday night through Monday night ridging will be in place over the
Great Lakes and believe our model blends are overdone in showing
light precipitation in the area. A front will sweep through on
Tuesday, but chances for showers with this front look limited due to
a lack of deep moisture.

- Warmer than normal through Tuesday then cooler

Warmer than normal temperatures are expected from Saturday through
Monday as highs should be in the 70s. Normal highs are in the middle
60s. Much colder air filters in behind the cold front on Tuesday
with 850mb temperatures dipping into the +2 to +4 C range Tuesday
night. Highs will be in the 60s post front on Tuesday and Wednesday.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 744 AM EDT Thu Sep 26 2024

Excellent aviation conditions are expected to prevail the next 24
hours. There will be some patchy fog for the next hour or so,
through 13z, otherwise VFR weather is expected. Some scattered
high clouds will be moving in this afternoon, with bases around
25,000 feet. Tonight, that cirrus will thicken and become a broken
deck. No restrictions to visibilities or low ceilings are
anticipated though this afternoon or tonight. Winds will be light,
under 10 knots through the period.

&&

.MARINE...
Issued at 350 AM EDT Thu Sep 26 2024

High pressure keeps winds and waves low today, then as the remnants
of Helene moves northwards, easterly winds will build Friday
afternoon and evening. Wind gusts on the order of 25 to 30 knots
look possible Friday afternoon and evening with the strongest gusts
along the southern half of Lake Michigan. Easterly winds will keep
wave heights on the West Michigan lakeshore to 1-2 feet, therefore
winds will be the primary hazard for the nearshore.

&&

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

&&

$$

DISCUSSION...Duke/Thielke
AVIATION...Duke
MARINE...Thielke