959
FXUS63 KGRR 150233
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
1033 PM EDT Tue May 14 2024

.KEY MESSAGES...

- Drying out tonight; sunny/dry for Wednesday

- Scattered showers return late Thursday and continue into Friday

- Warm with low chances for showers this weekend into early next
  week

&&

.UPDATE...
Issued at 1033 PM EDT Tue May 14 2024

Little movement in the key features is expected tonight with
surface high pressure situated over Ontario to our north and a low
meandering through the Ohio Valley. Northeast winds will continue
through the night. Aloft a weak trough will nudge to the east
allowing a small ridge to begin to push in. Given the above
factors, we see little in the way of change of conditions
overnight. Small chances for showers will continue in our south
overnight along I-94. Clouds will likely hang in through the night
over at least the southern half of the forecast area, or from near
I-96 to the south. Lows tonight should range from the middle 40s
up across Central Lower Michigan to the lower 50s along I-94.

&&

.DISCUSSION...
Issued at 340 PM EDT Tue May 14 2024

- Drying out tonight; sunny/dry for Wednesday

Low level convergence zone has set up near the Michigan/Indiana
border and SB Capes of 500-1000 J/KG related to earlier sunshine
has resulted in scattered thunderstorms. The storms are currently
tracking west and should remain south of the I-94 corridor based
on current radar trends. However would not totally rule out
additional development farther north especially if any outflows
from those push/fan out northward. Also the convection currently
in Lenawee County could clip the JXN area based on current
movement.

Meanwhile the band of showers farther north near GRR related to
mid level deformation have mostly faded with only a few lighter
showers/sprinkles remaining.

Once the diurnal convection in far srn Lwr MI dissipates after
sunset we should be largely dry overnight with only 20 pops
lingering into early Wednesday mainly near/south of I-94.

Drier air pours in from the north/northeast on Wednesday with
decreasing clouds occurring from north to south. Should be a
very pleasant day with plenty of sunshine, highs near 70, dew pts
in the 40s, and a fresh northeast breeze.

- Scattered showers return late Thursday and continue into Friday

Pleasant weather will persist early Thursday, with short range
models in good agreement that surface ridge will be overhead early
in the day. WAA will then increase later on Thursday as the
aforementioned ridge migrates east, and a 500 mb short wave trough
moves from northern Plains into Upper MS valley. This will set the
stage for scattered showers and thunderstorms late Thursday,
Thursday Night, and into Friday. Surface forcing weakens
considerably by Friday, in response to dampening upper trough.
However, still expect scattered /diurnally enhanced/ showers and
storms Friday with broad/weak trough aloft, daytime heating, and
lake breezes.

Low temperatures Thursday morning in the 40s will rebound into the
mid 70s Thursday afternoon. Highs on Friday will again reach the
70s. High temps both Thursday and Friday will be several degrees
above normal.

- Warm with low chances for showers this weekend into early next week

Temperatures are expected to remain above normal this weekend into
early next week. Though differences exist in the ensemble output,
the general trend is for the relatively zonal/progressive flow
pattern aloft to become slightly more amplified by early next week,
with troughing over the Pacific NW and downstream ridging over Upper
MS Valley and Great Lakes. This will support continued warm
temperatures, with highs in the 70s to around 80 /again, several
degrees above normal/.  Current ensemble output provides mixed
signals on whether weak short wave energy can still advance into the
Great Lakes, even as upper heights slowly build. As a result, the
forecast will reflect low chances /20-30%/ for showers Saturday, and
again Monday/Tuesday.

All in all, expect a decent stretch of weather this weekend and into
next week - especially for the mid-late May timeframe - with above
normal temperatures and occasional wetting showers.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 751 PM EDT Tue May 14 2024

This forecast period looks to be rather quiet with low impacts
expected. A mid cloud deck based around 9-11k ft agl remains over
all of the terminals as of 2330z. The southern sites have a lower
cloud deck around 4-5k ft agl also. Not really an issue with VFR
conditions at all of our terminals. Latest trend in the data
indicates that the clouds will be quicker to move out than
previous data. Some of the clouds will remain, but they just won`t
be as widespread. High clouds may linger longer.

The only change in the conditions for tomorrow will be less mid
cloud cover, and maybe some diurnal cumulus the further south and
east you go. The cumulus bases are expected to be VFR around 3-4k
ft agl. KMKG will see a lake breeze kick in around 16-18z or so
where the wind will switch around to be from the NW.

&&

.MARINE...
Issued at 340 PM EDT Tue May 14 2024

The Big Sable Point observation indicates that the stronger
northerly winds of 15-20 kts has developed near the Points as
anticipated. There may be a further increase in winds north of
Whitehall through sunset before falling off and turning more
northeasterly after dark. Since the duration of these increased
conditions should be brief will not have a Small Craft Advisory.

A similar situation is shown for Wednesday afternoon, with
northerly flow strengthening over the entire nearshore by mid
afternoon and continuing through sunset. Otherwise little support
for hazardous marine conditions through the rest of the week.

&&

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

&&

$$

UPDATE...Duke
DISCUSSION...Meade/Smith
AVIATION...NJJ
MARINE...Meade