355
FXUS63 KAPX 290800
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
400 AM EDT Mon Jun 29 2026

.KEY MESSAGES...

- Showers and thunderstorms this morning, best potential NW
  lower MI, then eastern UP into the early afternoon.

- Hot and humid conditions through this week, heat indices between
  95F to 105F Tuesday through Thursday.

- Periodic thunderstorm chances through this upcoming week, a
  few periods of stronger storms possible.

&&

.DISCUSSION...
Issued at 247 AM EDT Mon Jun 29 2026

Pattern Synopsis and Forecast:

Showers and thunderstorms are expected to develop this morning
within a warm and moist advection regime, with instability axis
northwest to southeast across the Upper Midwest nosing into western
MI. The best elevated instability and moisture will be across
northwest lower Michigan (where the current Marginal risk for severe
weather lies). Moderate amounts of shear could result in some
elevated hailers, although some of the convective allowing models
are showing a convective complex congealing over Lake
Michigan/Wisconsin and clipping the Marginal risk across our area
this morning, which could produce strong winds in some places. Given
the instability, shear, and moist airmass, locally heavy rain,
localized hail, and strong winds will be the primary concerns this
morning, with some showers and storms lingering through the
day. Current radar imagery is not quite as robust in WI as some
of the previous guidance suggested, so worth monitoring as the
POP fcst may be a little off.

Heat will generally be the focus the rest of the week. 596-597 dam
upper high builds across the Southeast and Ohio Valley, with
anomalous heights across northern MI. Most recent model guidance
runs do show this upper high slowly meandering eastward with time
through the end of the week, which continues the theme of
uncertainty in regards to the heat. That being said, it will be hot
and very humid, especially for northern MI, this entire week, so
regardless, heat stress will be high and compounded with time.
After the showers and storms today, a pretty hot day is expected
with heat indices in the 80s and 90s, hottest GTB and southwest
(thought about an advisory for that region but with the
uncertainty and the focus being Tuesday, twas will forego).
Hottest day appears to be Tuesday, with heat indices in the mid
90s to triple digits. Then we watch how much convection on
Wednesday and Thursday tries to impact the high temperatures.
Current forecast has highs well into the 90s most areas both
Wednesday and Thursday with heat indices in the mid 90s to mid
100s.

Heat is a compounding hazard, and so several days of heat indices
near 100F may mean more than a single day of a heat index 105F.
Because of this, Extreme Heat Watches have been issued for all of
northern lower MI, the hottest temperatures and heat indices being
across northeast lower MI. Whether some sections of this will
be upgraded to Advisories or Warnings, will be up to the day
crew most likely. The message remains the same regardless, heat
stress will be high this week due to the heat and humidity.
Check on those sensitive to heat, outside workers, and pets.

Investigating the other convective threats through the week yields
modest southwest flow overspreading the Upper Midwest, including
northern MI, overtop of this moist and unstable airmass. As the high
pressure slides to the east, this may open the door for subtle
perturbations and convective complexes to ride the northern
periphery of the ridge, resulting in showers and thunderstorms across
northern MI. Given the amount of instability, expected convection
upstream, and increased flow aloft, there could be severe threats at
times for sure. Current guidance indicates the later Tuesday
time frame and the Thursday to Friday being potentially active.
As far as Tuesday is concerned, a Marginal risk (level 1 of 5) for
severe thunderstorms is forecast, with portions of the Eastern
UP in a Slight risk (level 2 of 5). Thus, isolated severe
storms are possible during this time frame. Looking at the
later Tuesday and Tuesday night time frame mostly. Moderate
shear and plentiful instability is usually a hail/wind risk,
especially if any bowing segments or mesoscale convective
complexes can push into northern MI. Many details to hash out
beyond that in regards to convection.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 355 AM EDT Mon Jun 29 2026

Expect at least a broken band of showers and embedded
thunderstorms to potentially impact all sites other than KAPN
this morning, with the shower threat ending from west to east
later this morning and afternoon. Confidence in coverage of
storms remains low, so not all locations may be impacted. Cloud
bases should remain elevated, but cannot rule out some brief vis
restrictions and gusty winds with any stronger storms. Radar
trends will continue to be monitored for future
adjustments/amendments. Looking at VFR conditions through tonight,
although will need to watch for some early morning stratus to
develop at KCIU. Southeast to south winds do become a bit gusty
today into this evening.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Extreme Heat Watch from Tuesday afternoon through Thursday
     evening for MIZ016>018-020>036-041-042-097>099.
MARINE...Small Craft Advisory from 11 AM this morning to 11 PM EDT this
     evening for LHZ345>348.
     Small Craft Advisory until 8 AM EDT Tuesday for LMZ344>346.

&&

$$

DISCUSSION...JLD
AVIATION...MSB