National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KGRR 112331
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
731 PM EDT Thu Apr 11 2024

.KEY MESSAGES...

- Rain Continues into Friday, Strong Winds Friday

- Chance for Showers and Storms Saturday Night/Sunday AM

- Warm Next Week with Storms Tuesday into Wednesday

&&

.DISCUSSION...
Issued at 301 PM EDT Thu Apr 11 2024

- Rain Continues into Friday, Strong Winds Friday

Scattered showers will continue off and on through tonight and
into the first part of Friday before drying out later Friday
afternoon. This is due to the upper level low moving overhead with
positive vorticity advection continuously rotating around the low
until it shifts east on Friday. Rainfall amounts are lower than
previously forecast due to the overall eastward track of the
surface low. Additional amounts around two tenths to 3 quarters of
an inch are possible through Friday with the highest amounts along
the 127 corridor.

As the low pressure system system shifts northeast we`ll see a
phasing of two upper level waves causing the low to deepen. With a
tighter pressure gradient winds at the surface and aloft are
expected to increase into Friday. With 925 mb winds around 40
knots and 850 mb winds around 50 knots gusty northwest winds are
expected. Looking at soundings sustained winds of 20 to 30 mph
with gusts of 40 to 50 mph are expected Friday, with peak wind
gusts during the afternoon. A Wind Advisory has been issued for
the entire area. Make sure to secure any loose objects outside,
tree damage and power outages will be possible.

- Chance for Showers and Storms Saturday Night/Sunday AM

We are still looking at a brief period of some showers and storms
coming through much of the area Saturday night into Sunday. After
short wave ridging and high pressure at the sfc move by late
Saturday, we will see a short wave and sfc front drop through on NW
flow aloft. Each of these features will not be all that strong, but
it does look like we will see an elevated mixed layer (EML) interact
with the wave and provide the threat for showers/storms. These
should be elevated in nature, so the threat of strong to severe
storms will be on the lower side.

The wave will move by, and should be SE of the area by sunrise
Sunday morning. This will allow for mainly dry and near seasonable
temperatures. High pressure will then build in once again, and
dominate the weather over the area through Monday night. Return flow
from the SSW will bring warmer temperatures into the area for Monday.

- Warm next week with Storms Tuesday into Wednesday

We continue to watch a storm system that will be organizing to our
west, and approaching the area on Tuesday. It does seem that we will
see a good chance for showers and storms for most of the area as we
will see a good feed of Gulf moisture out ahead of the large upper
system going negatively tilt as it approaches the area.

The main question will be how much potential there is for severe
weather. As mentioned above, the system is becoming negatively
tilted as it approaches the area. We will have the warm sector
approaching the area with the really good instability to tap. Right
now, it does look like the system will be occluding as it approaches
and the exact track of the warm sector remains uncertain. It all
depends on how the exact track of the upper jet streak traverses the
region.

With the low closed off, it will take a while for it to move out of
the area sufficiently to bring the rain to an end and dry the area
out. Improving conditions should occur Wednesday into Thursday. We
stay in a SW flow aloft through Thursday that will keep the area
under warmer conditions. Eventually, another strong system will
eject from the long wave trough over the western states. Right now,
this looks like it will be mainly focused beyond this forecast
period.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 730 PM EDT Thu Apr 11 2024

Impacts to aviation are expected throughout the TAF period.
Initially, the primary impact will be low clouds as a system
moving to our southeast keeps conditions IFR or lower though mid-
day Monday for all sites except MKG. JXN has the best chance to
see LIFR conditions with a low chance at LAN as well. MKG looks to
mostly remain outside of the IFR shield but occasional drops to
IFR are possible early Friday morning. Rain showers continue into
the mid-day period Friday, with MVFR visbys with localized
pockets of IFR for areas south and/or east of GRR. Rain showers
end and visbys climb to MVFR then VFR Friday afternoon as drier
air moves in.

The other impact will be the wind. Generally northwest of 10-15
knots with gusts to 25 knots are expected tonight. These winds
then substantially increase late Friday morning with 20-25 knot
northwest winds gusting to 40 knots expected through the rest of
the TAF period.

&&

.MARINE...
Issued at 301 PM EDT Thu Apr 11 2024

Gusty northeast winds will build into tonight and shift to the
northwest causing wave heights to increase. With the low pressure
system tracking through the eastern Great Lakes, the pressure
gradient associated with the low will tighten over the area
resulting in northwest gales for all of the nearshore zones Friday
morning and through the afternoon. Winds and waves will gradually
fall Friday night where another Small Craft Advisory will likely
be needed before conditions improve Saturday morning.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Wind Advisory from 8 AM Friday to 2 AM EDT Saturday for
     MIZ037>040-043>046-050>052-056>059-064>067-071>074.
MARINE...Small Craft Advisory until 8 AM EDT Friday for LMZ844>849.
     Gale Warning from 8 AM to 6 PM EDT Friday for LMZ844>849.

&&

$$

DISCUSSION...NJJ/RAH
AVIATION...Thomas
MARINE...RAH