207
FXUS63 KAPX 212318
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
718 PM EDT Tue May 21 2024

.KEY MESSAGES...

- A strong to severe line of storms is possible late this
evening/tonight. The primary threat is damaging winds, with large
hail and a tornado or two also possible.

- Pleasant temperatures but with occasional rain chances for the
Memorial Day weekend.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 326 PM EDT Tue May 21 2024

Pattern/synopsis: Surface low pressure (currently 995 mb across
western Iowa) is shown to deepen to 981 mb by Wednesday morning
while tracking well northwest of the region.

Forecast: Tonight...As the deepening area of low pressure tracks
from the central Plains into the northern Mississippi Valley, a line
of strong to severe thunderstorms is expected to march across
Wisconsin this evening, possibly reaching far western zones of
northern lower just before midnight. Strong winds aloft (0-6 km bulk
shear 50 to 60 knots) will likely accompany the line as well as the
potential for large hail and perhaps even a tornado or two given the
strong speed and directional shear. The latest SPC outlook continues
the enhanced risk for severe storms near Manistee with a slight risk
across much of the remainder of northern lower. However, the
combination of the loss of daytime heating and the relatively cold
waters of Lake Michigan will make it tough for any line of strong to
severe storms to hold together this far east. A vast majority of
model guidance is on board with this thinking and has the line
weakening/splitting/falling apart as it progresses across the big
lake. Although it looks doubtful, there is still a small chance
chance that it could still impact parts of the region, especially
along and near Lake Michigan. Most guidance doesn`t give the line
much of a chance of holding together east of I-75 on toward Lake
Huron. Time will tell on this one and this will be monitored by the
evening shift for current trends. Muggy tonight with lows only in
the upper 50s to mid 60s.

Wednesday...Subsidence behind the departing system is expected to
lead to at least partly sunny skies. Downsloping east of I-75 is
expected to lead to highs of well into the 70s to around 80. Highs
to the west in the low and mid 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 326 PM EDT Tue May 21 2024

PATTERN SYNOPSIS/FORECAST:

A closed low will slowly track eastward as shortwave ridging builds
across the Midwest in response to troughing digging across the
Plains, and eventually towards Lake Superior. SW winds will turn W
for Thursday and then slowly turn more N for Friday in response to
the aformentioned features influencing the forecast area. Ridging
and high pressure will provide moderating temperatures into the
weekend, with highs more seasonable in the 60s and 70s for Memorial
Day weekend as flow turns more zonal. For Thursday, areas along the
Lake Huron side could reach the 80s as W flow downslopes. Long term
guidance suggests energy quickly tracking overhead through Friday
night, bringing about the next appreciable shower chances to the
region. The aforementioned trough will also bring more shower
chances to the region for the holiday weekend.

PRIMARY FORECAST CONCERNS:

- Holiday weekend: Looks like an exceptional holiday weekend with
moderating seasonal temperatures and mostly clear to sunny skies
with some chances for showers at times. Daytime highs look to be in
the 60s/70s for most, and potentially in the 80s for those in the
southern-most locations of the forecast area. Friday night into
Saturday continues to be the most likely timeframe for rain
showers, and potentially a rumble of thunder or two. Looking at
Sunday night into Monday, chances for showers pop up again as a
trough and its associated low pressure tracks to Lake Superior.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 713 PM EDT Tue May 21 2024

VFR through this evening with focus revolving around a line of
severe thunderstorms upstream currently across far western WI,
eastern IA/MN. Latest trends support this line dissipating as it
approaches during the late evening/overnight, but still enough
support to include TSRA/VCTS at the terminals with the highest
chances at CIU/PLN/TVC. CIGs/VSBYs briefly falling to IFR/MVFR
in any heavier thunderstorms.  Lower clouds likely to move in
late tonight/early Wednesday morning with skies clearing through
the day Wednesday. LLWS expected tonight, along with occasionally
gusty surface winds. Erratic and and stronger gusts possible in
and near and thunderstorms tonight.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT Wednesday for LMZ323-341-
     342-344>346.
     Small Craft Advisory from midnight tonight to 8 PM EDT
     Wednesday for LSZ321-322.

&&

$$

SHORT TERM...AJS
LONG TERM...NSC
AVIATION...MJG