Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 250125

Area Forecast Discussion
National Weather Service Gaylord MI
925 PM EDT Sun May 24 2020

Issued at 924 PM EDT Sun May 24 2020

Last of the showers departed ne lower MI late this afternoon,
a little behind schedule. As expected, a relative lull in wx
across northern MI this evening, with decreasing cloud cover over
much of the area. However, marine fog/stratus has made a
significant expansion at the end of the day, especially in the
Straits area (per webcams) and on far northern Lake MI. Some
1/4SM vsbys are seen at Mack Isl/ISQ/Beaver Isl/Harbor Spgs. This
fog push will likely slow to some degree tonight, as lake breeze
circulations weaken. But will amp up coastal fog wording, and
certainly not inconceivable that some fog advisories may be in
order over land (some are already in place on NSH waters).
Elsewhere, some patchy fog will eventually form over inland areas
as well.

An uptick in warm/moist advection at mid levels is still expected
to arrive late tonight. This will steepen lapse rates, and perhaps
contribute to accas and a few showers. But CAMs are showing less
in the way of QPF than they did earlier in the did, and there is
very little in the way of mid clouds out there now. Will maintain
a small chance for a late-night shower or two, mainly over and
near Lake MI, historically the favored spot for late-night warm-
season elevated showers to pop.


.NEAR TERM...(Through Monday)
Issued at 311 PM EDT Sun May 24 2020

...Unseasonably Warm & Humid for Monday...

High Impact Weather Potential...Low overall, put patches of dense
fog are possible tonight, and a few thunderstorms (non severe) are
likely across northern Lower MI Monday afternoon.

Pattern Synopsis/Forecast...A summer-like pattern will persist
across eastern Upper and northern Lower MI into the Memorial Day
holiday (and beyond). Mean upper-level ridging will will continue to
hold in place over about the eastern half of the Lower 48 through
the period. Gulf moisture continues to stream northward on the warm
side of the mean central U.S. trof/ridge boundary which is helping
unseasonably muggy conditions to develop across MI.

There have been periodic disturbances embedded within the mean flow,
like the one that is moving through today, that have enhanced shower
and/or storm chances within the at least slightly unstable local air
mass. The next disturbance moves through the region later tonight,
with the latest guidance suggesting spotty showers over the western
portion of the forecast area late tonight. The lack of deep mixing
today, and increasing low-level moisture through the night, should
also produce areas of low clouds and fog overnight.

A lull in the shower threat is likely again Monday morning, but with
with building humidity expect scattered showers/storms to fire
during peak afternoon heating. Latest forecast soundings suggest
CAPE values averaging 1000-1500j/kg Monday afternoon over northern
lower MI (lower across the eastern UP). There will not be much
dynamic/wind support for organized storms, but some slow moving
heavy rainers are a distinct possibility with precipitable water
values from 1.5" - 2.0" over most of the area. Temperatures Monday
will be the warmest of the year over much of the forecast area, with
widespread 80s away from the lakes.


.SHORT TERM...(Monday night through Wednesday)
Issued at 311 PM EDT Sun May 24 2020

High impact weather potential: Chances of thunderstorms each
day...especially during the afternoon and evening hours.

Southwesterly flow will continue to pump in Gulf moisture throughout
the short term forecast period, producing a warm and humid air mass
with the possibilities of showers and thunderstorms...especially
during the afternoon and evening hours. Strong Bermuda High and low
pressure over the Oklahoma area will be the cause of this continued
southwesterly flow advecting Gulf moisture and warm temperatures
into the forecast. PWATS are progged to be between 1.50 to 1.75"
during this time frame. MLCAPE of between 500-750 during peak
heating will be enough to produce some moderate to heavy rain
showers and possibly some thunder...especially with some steeper
lapse rates and dew points around 65 degrees with not much of a cap
on forecast soundings.

As mentioned above, winds will be southwesterly throughout this
forecast period, with gusts to 20-25 kts during the afternoon and
lighter during the overnight and morning periods.

Daytime temperatures will be above normal for this time of the
year...reaching into the mid to upper 80s Tuesday and the upper 70s
to low 80s Wednesday, with eastern upper only reaching into the 70s.
Some portions downwind from the Great Lakes will also be much cooler
(Mackinac Island is only 46 degrees at this time, while the inland
areas of the forecast period is around 70. Low temperatures
Monday and Tuesday night will be in the mid 50s to low 60s.

.LONG TERM...(Wednesday night through Sunday)
Issued at 311 PM EDT Sun May 24 2020

High impact weather potential: Thunderstorms possible, especially
during the late afternoon/evening hours for several days.

Several disturbances will roll through northern Michigan throughout
much of the extended period...producing chances of showers and
thunderstorms throughout much of the period. The best chances for
some precipitation-free days will be during the weekend as surface
high pressure builds into the area. High temperatures will be in the
low 70s to near 80 Thursday and back down to near normal (around 70)
to start next weekend as the aforementioned surface high pressure
builds in.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 727 PM EDT Sun May 24 2020

Fog/stratus overnight and early Monday APN/PLN.

Showers have departed ne lower MI, as a weak area of low pressure
heads in the same direction. Fog and stratus originating from Lake
Huron is expected to gradually press inland, bringing MVFR and
then IFR conditions to APN and PLN, toward and especially after
midnight. Some showers could also resume very late tonight, as
another push of moist air occurs. Sct showers and t-storms are
expected Monday afternoon, but primarily inland from the Great
Lakes and inland from all four of our TAF sites.

Continued weak winds. Lake breezes Monday afternoon.


Issued at 311 PM EDT Sun May 24 2020

Generally light winds and slight waves anticipated over the next
couple of days. The main exception to this would be with an isolated
thunderstorm, but few are expected over the lakes. Otherwise, a more
humid air mass into midweek will continue to produce at least patchy
fog, some of which will be dense.


LM...DENSE FOG ADVISORY until noon EDT Monday for LMZ341-342-344>346.


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