-- Discussion containing changed information from previous version are highlighted. --
779
FXUS63 KGRR 032357
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
757 PM EDT Fri May 3 2024

.KEY MESSAGES...

- Increasing Chance for Showers/Storms Later Saturday into
  Saturday night

- Dry end of the weekend

- Many chances for rain next week

&&

.DISCUSSION...
Issued at 231 PM EDT Fri May 3 2024

- Increasing Chance for Showers/Storms Later Saturday into
  Saturday night

Southerly winds ahead of an approaching cold front will draw up
moisture from the south Saturday into Saturday night. Instability
increases as well later Saturday afternoon into Saturday night,
but overall remains weak. Aloft some upper level divergence is
seen Saturday night over the CWA so that may enhance the lift.
Thus the combination of moisture, lift and instability will likely
lead to showers and a few storms. Ensemble QPF values, while low,
have been trending up with the precipitation for this period.


- Dry end of the weekend

High pressure over the upper Mississippi Valley will produce plenty
of sunshine Sunday. Highs will climb to a couple of degree either
side of 70.

- Many chances for rain next week

The persistent upper trough over the western US is progd to cut off
over the northern High Plains during the middle of the week. The
result will be several short waves that move in our direction and
bring chances for showers and storms.

Tuesday night through Wednesday night will be a time frame that will
see increased chances for precipitation. An occluded front will lift
north toward Lower MI Tuesday afternoon and this will produce some
showers/storms. Present indications are that the strongest
instability will remain south of the state. However, that could
changed this far out. SPC has already highlighted areas to the
southwest of the state for the potential of severe storms.

Another chance of showers/storms will come Thursday and Thursday
night, when the surface low over the northern Plains moves east.
Accompanying short waves and a feed of moisture rich air from the
south will spur convective development during this time.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
-- Changed Discussion --
Issued at 757 PM EDT Fri May 3 2024

A combination of lingering low level moisture that will not
decrease substantially behind this afternoon`s cold frontal
passage and a flow off of Lake Huron will produce stratus and fog
tonight. We will be VFR through any flights at the TAF sites
through 05Z or so. After 05Z, the stratus and fog will be making a
push into Southwest Lower Michigan from the east. MVFR and IFR
ceilings will develop at LAN and JXN around 06Z and overspread
GRR/BTL and AZO by 09Z. The stratus will press into MKG by 11Z.
The lowest conditions, IFR and potentially LIFR will occur between
09Z and 13Z. Low clouds will lift to VFR through the daylight
hours of the Saturday morning (12Z-16Z). VFR weather is expected
Saturday afternoon. Winds will become east tonight and gradually
become southeast and south on Saturday.
-- End Changed Discussion --

&&

.MARINE...
Issued at 231 PM EDT Fri May 3 2024

Southerly flow will be on the increase Saturday into Saturday
night as a front moves in from the west. This will be warm air
advection and overall the values are expected to remain under 20
knots. Thus we don`t plan on needing headlines a this time.

&&

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

&&

$$

DISCUSSION...MJS/04
AVIATION...Duke
MARINE...MJS