142
FXUS63 KAPX 221050
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
650 AM EDT Wed May 22 2024

.KEY MESSAGES...

- Thunderstorms linger into the morning hours.

- High swim risk across most Lake Michigan counties.

- Showers in the eastern U.P. Thursday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 349 AM EDT Wed May 22 2024

Pattern Synopsis:

Potent shortwave troughing will continue to lift across the northern
Great Lakes over Ontario today as broader troughing settles over
most of the north-central CONUS. This system will become
increasingly vertically stacked with time as the associated sub-
990mb surface cyclone pivots from the Upper Midwest into Ontario
later today.

Forecast Details:

Thunders linger into the morning hours -- Multiple thunderstorm line
segments continue to work across northern Michigan and the Great
Lakes waters. These storms are expected to sustain themselves over
the next several hours into the morning amidst elevated instability
on the order of 500-1,000 J/kg and strong shear in excess of 40 kts.
This environment will continue to support strong thunderstorms
capable of gusty winds and small hail. Most storms will track across
areas that have already been convectively overturned so far tonight,
giving low confidence in severe wind gusts reaching the surface with
any storms -- although a non-zero severe threat still remains,
including any storms along/out ahead of remnant outflow boundaries.
Storm chances will diminish into mid/late morning as favorable
forcing becomes increasingly displaced from northern Michigan.
Otherwise, a short break in precip chances may materialize before
additional scattered showers return to the eastern U.P. into this
evening.

High swim risk for most Lake Michigan counties -- Southwest to south-
southwest winds around 15 kts with gusts between 20-30 kts will
bring a high swim risk to most Lake Michigan counties today due to
dangerous waves and currents. The exceptions will be Grand Traverse
and Antrim counties as Grand Traverse Bay will be sheltered from
strongest winds/waves, and is expected to remain below criteria.
Regardless of swim risk for your area, cold water temperatures in
the upper 40s and 50s Fahrenheit will still bring the risk of
hypothermia for those in the water without proper
equipment/protection.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 349 AM EDT Wed May 22 2024

Pattern Synopsis / Forecast:

Cutoff low set to be slowly moving east from Hudson Bay on Thursday
as ridging begins to intrude into the Great Lakes. Weak wave riding
progressive flow regime coupled with lingering moisture in
conjunction with the departing low will be enough to spark some
diurnal showers across eastern upper through the afternoon on
Thursday. Lesser moisture concentration and aggressive mixing should
erode most shower chances across northern lower. Ridging axis moves
overhead for Friday, with southerly flow dominating. Result will be
a return of summer like warmth as highs rocket back into the upper
70s and lower 80s (perhaps mid 80s for some). Next rain chances show
up as shortwave trough and associated surface low pass through Lake
Superior Friday night into Saturday morning. On its heels, another
wave passes into the Great Lakes Sunday into Monday. Current
thinking is that this wave stays well to the south and we hold on
the drier side of things.

Primary Forecast Concerns:

Thursday Showers in the Eastern Yoop: Diurnal instability progged at
several hundred joules should be able to generate some showers in
the eastern Yoop Thursday afternoon with the help of a subtle
perturbation passing through the upper Great Lakes. Unidirectional
flow and some speed shear creates more of a linear hodograph.
Outflow dominant showers and some thunder appear possible, and
perhaps a storm approaches marginally severe status at peak heating.
Primary hazards will be gusty winds and small hail.

Weekend Outlook: Warm temperatures expected Friday as ridging moves
overhead with southerly flow. Given 850mb temps in the low to mid
teens Celsius and good mixing, should be enough to rocket temps well
into the 80s across northern lower and low-to-mid 70s in the eastern
Yoop. Quick moving area of low pressure passes into Lake Superior
Friday night, and its attendant cold frontal boundary is progged to
bring about some scattered showers into the overnight hours Friday
night. Given the efficiency of mixing Friday, might make instability
hard to come by, so not a lot of stock being put into this rain
chance. Big story will be the more seasonable air in its wake, with
highs falling back into the 60s and 70s for the remainder of the
holiday weekend. Presence of high pressure could lead to some pretty
aggressive diurnal cooling responses in the overnight hours this
weekend, so may need to watch for an outside frost / freeze threat
if clear skies can accompany decoupling winds. Larger system set to
pass to the south to close out the holiday weekend. Dry northerly
flow from high pressure over Ontario should stunt northward advance
of rainfall associated with this system, so my inkling is that the
rest of the holiday weekend probably holds dry, save for perhaps a
shower or two near Saginaw Bay Sunday night into Monday owing to
their closer proximity to the passing low. All in all, definitely a
much drier weekend than not.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 649 AM EDT Wed May 22 2024

MVFR CIGs are expected to settle in across the western TAF sites of
MBL, TVC, and PLN over the next few hours. IFR/LIFR CIGs may linger
for the next few hours at CIU as well, but should lift to MVFR by
mid morning. VFR conditions are anticipated across northern lower
Michigan by mid afternoon, and perhaps a slightly later across the
eastern U.P. Mainly southwest winds around 15 kts with gusts between
20-30 kts today will weaken heading into tonight.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through this evening for MIZ016-020-
     025-031-095-096-098-099.
MARINE...Small Craft Advisory until 10 PM EDT this evening for
     LHZ345>349.
     Small Craft Advisory until midnight EDT tonight for LMZ323-341-
     342-344>346.
     Small Craft Advisory until 8 PM EDT this evening for LSZ321-
     322.

&&

$$

SHORT TERM...DJC
LONG TERM...HAD
AVIATION...DJC