115
FXUS63 KGRR 162349
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
749 PM EDT Thu May 16 2024

.KEY MESSAGES...

- Scattered showers and storms tonight/early Friday

- Dry and Mild Weekend

- Active Weather to Start the Work-Week

&&

.DISCUSSION...
Issued at 328 PM EDT Thu May 16 2024

- Scattered showers and storms tonight/early Friday

A shortwave and accompanying sfc frontal boundary track slowly east
through the region tonight and Friday morning, but are generally
weakening as they do so. Instability isn`t the greatest either
especially since these features come through mostly during the
diurnal minimum.

Initially this evening scattered showers and storms will be
associated with the incoming warm front and higher dew points,
then overnight will be linked more to the nearing WI shortwave and
cold/occluded front. HREF guidance suggests best coverage of rain
will be during the overnight period especially east of Hwy 131.

Will carry some lingering low (20-30 pct) pops Friday mainly
near/east of U.S. 127 and near/south of I-94 since the sfc front
stalls out and there is still some lingering sfc instability
(SBCapes 500-1000 J/KG). Otherwise decreasing clouds and a warm
Friday expected with highs in the upper 70s. May have to consider
a risk of patchy fog Friday night in light wind/clear sky regime.

- Dry and Mild Weekend

High pressure moves into the region resulting in dry weather this
weekend. An 850mb thermal ridge peaking at +12 to +14C moves
overhead Saturday and Sunday resulting in high temperatures into the
80s with plenty of sunshine.

- Active Weather to Start the Work-Week

A deepening longwave trough will eject out of the Rockies at the
start of the work week sending a series of shortwaves through the
Great Lakes Region. This will result in an active weather pattern
through the first half of the week with showers and storms possible.

The first round of storms will move through Monday evening as a
front sweeps through the area. Instability looks sufficient ahead of
the front to support some showers and storms Monday evening, but the
better chance appears to be Tuesday afternoon and evening. As a more
potent shortwave moves overhead, a surface low will track through WI
into the UP while a trailing cold front sweeps through the state.
Instability will build throughout the day Tuesday ahead of the front
while a 40 to 50 knot Low Level Jet noses into Michigan during the
evening. Model guidance has yet to come into good agreement
therefore confidence remains low, but Tuesday may be a day to
monitor the the potential for strong to severe storms in the area.

Temperatures will drop closer to normal (normal highs are around 70)
Wednesday and Thursday following the passage of the front.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 749 PM EDT Thu May 16 2024

Scattered showers and isolated thunderstorms will impact the
terminals this evening with brief drops in visibilities to MVFR
or lower possible in any heavier showers/thunderstorms. Cigs and
visbys drop to MVFR/IFR areawide after 07z with restrictions
continuing into Friday morning as winds calm overnight. MKG has
the potential to reach LIFR at times near daybreak due to
influence from the lake. Conditions improve over the course of mid
to late Friday morning with conditions reaching VFR early Friday
afternoon. Southerly winds of 5-10 knots tonight become light
overnight and become westerly at 5-10 knots Friday.

&&

.MARINE...
Issued at 328 PM EDT Thu May 16 2024

Fairly high confidence in relatively light winds/low waves
through the weekend with no Small Craft Advisories anticipated.
However we may be dealing with areas/periods of marine fog over
the next several days as higher dew points in the mid to upr 50s
arrive and stick around.

&&

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

&&

$$

DISCUSSION...Meade/Thielke
AVIATION...Thomas
MARINE...Meade