436
FXUS63 KAPX 111717
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
117 PM EDT Mon Aug 11 2025

.KEY MESSAGES...

- Showers, storms, and downpours focus on eastern upper and
  northwest lower through the morning. Primary concern is heavy
  rainfall.

- Additional shower and storm development anticipated this
  afternoon across the rest of northern lower. Primary concern
  is brief torrential rain, though a gustier storm is possible.

- More of the same, with warm conditions and periodic shower and
  storm chances into Tuesday.

- A bit less warm and humid Wednesday into Thursday, with more
  warmth, humidity, and rain chances building heading into next
  weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 241 AM EDT Mon Aug 11 2025

Current Overview / Pattern Synopsis:

Longwave troughing over Ontario will continue to move north and
east, with a slowing north to south cold front draped from
western upper Michigan to roughly Jefferson City, MO continuing
its slow eastward advance. Here in northern Michigan, we will be
delicately placed between this feature and a ridge axis
advancing eastward through Ontario and Quebec. This will keep a
moist airmass throughout the region over the course of the
forecast period, which will bring rounds of showers and storms
to northern Michigan over the next 24 to 36 hours. Finer details
showcase a corridor of stronger LLJ flow, which is inducing
convection just off the Lake Michigan shore as of 06z Monday,
with a subtle eastward advance placing that activity across
northwest lower Michigan. There is also a pseudo-organized
mesolow approaching Green Bay, WI, which will drift north and
east the rest of tonight, passing through the region this
morning, bringing potential for a round of showers and thunder
across the Straits and the eastern Yoop. This feature will
likely throw a weak outflow boundary across the rest of the
region from west to east, which will bring about shower and
storm potential across the rest of northern lower (I.E., east of
US 131) as this area of convergence provides a source of lift
in an increasingly unstable airmass this afternoon.

Forecast Details:

Some concern regarding the convection across northwest lower the
rest of tonight. Latest mesoanalysis showcases a quickly moistening
profile (on the order of 2.0+ PWATs across southeast Wisconsin into
central Lake Michigan). This moist environment looks to overlap with
continued convective initiation across far eastern Lake Michigan,
slowly intruding across northwest lower with time. Considering such
a moist environment, along with echo training already noted over the
lake, this could turn into a setup for locally heavy rainfall,
possibly in the order of 1.50"+ in some of the shore locales from
Leelanau to Manistee counties by the time this feature departs this
morning. Lack of organization should prevent a more robust rain
outburst (and thus anything more than marginal flooding concerns).
Much of the same can be said for the mesolow as it traverses the
Straits into eastern upper... this feature should remain transient
enough to mitigate hydrologic concerns as well, though locally heavy
rainfall is certainly on the table.

Into later this afternoon, a weak wind-shift / outflow boundary will
provide a source of lift for storms across the rest of northern
lower. Activity will likely be widely scattered to isolated between
US 131 and I-75 before becoming a bit more widespread across
northeast lower. Again... some of this activity may present a brief
torrential rainfall threat, but all in all, this activity also looks
to be transient enough to prevent flooding concerns. As is a common
case with afternoon storms in northern Michigan... widespread severe
storms are not anticipated, but within any more robust updrafts,
certainly possible for some gusty winds. At this juncture, the warm
nature of the airmass and elevated hail layer, coupled with abysmal
shear (bulk shear again less than 20kts today) would make it
difficult to attain much more than some small hail in the most
robust of storms.

Looking into tonight, will have to watch how a more robust
convectively charged wave evolves as it lifts along the front from
Missouri into the Great Lakes late tonight. Some guidance wants to
bring this feature into northern Michigan, possibly complete with a
mesolow, which could bring about another round of nocturnal showers
and storms late tonight. More details to come.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 241 AM EDT Mon Aug 11 2025

There is relief in the air for those weary of the heat and humidity
as we get to midweek, but we will have to contend with one more day
of humid weather and storm chances as we get through Tuesday. The
aforementioned cold frontal boundary will finally pass through the
region as a more defined area of longwave troughing passes through
northern Michigan Tuesday. Not much sticks out in regard to heavy
rain at this juncture, as any activity along the front will likely
hold transient enough once the front is forced through (accelerating
in the process). We will have to watch and see if any linear
convective segments can materialize on the front itself, which could
pose a severe threat, particularly across the western half of the
CWA given a potential evening / early overnight passage. In the wake
of this frontal passage, cooler and drier air briefly fills in, with
highs largely in the 70s and overnight lows generally 45 to 55
(coolest across the interior). The front won`t remain past us for
long... as another ridge builds and southerly return flow draws the
front (and the heat / humidity with it) back into northern Michigan,
and reintroducing shower and storm chances across the region this
upcoming weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 111 PM EDT Mon Aug 11 2025

MVFR/IFR conditions at times due to VCTS/TSRA around northern MI
to day. Skies generally SCT-OVC at varying heights with vis
reduced under RA. A weak FROPA is currently moving from west to
east over the region and will breifly turn winds W/SW before
winds return to SW. Winds are generally 10 to 15kt with G15 to
25kts (stronger one near TS). Storms will continue to form
in front of or along FROPA through 22Z. Most activity should
move out or diminish after 03Z. More chances for VCTS/VCSH near
KMBL/KTVC around 10Z.

&&

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

&&

$$

SHORT TERM...HAD
LONG TERM...HAD
AVIATION...ELD