759
FXUS63 KAPX 021901
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
301 PM EDT Tue Jul 2 2024

.KEY MESSAGES...

- A few thunderstorms producing locally heavy rain at times
  tonight.

- Trending dry for the Independence Day holiday (Thursday).

- Heavy rain and possible stronger storms return for the weekend.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 259 PM EDT Tue Jul 2 2024

Pattern Synopsis/Pattern Forecast:

Increasingly moisture rich southwest flow overspreading the area
early this afternoon...with northern Michigan sandwiched between
Gulf States centered subtropical ridge and broad troughing slicing
east across central Canada into the northern Plains. Initial wing of
moisture advection into the region mostly of the elevated type, with
stubborn to yield low level dry air remaining the main detriment to
more widespread rain this afternoon. Juxtaposition of better deep
layer moisture advection and a more unstable atmospheric profile
remains just a bit upstream, and that indeed is where the most
organized and intense rain has remained.

Upstream troughing and embedded shortwave will continue to work east
into the western Great Lakes tonight into early Wednesday. Attendant
cold front will lead the charge, bringing with it a more organized
rain threat tonight.

Primary Forecast Concerns/Challenges:

Main focus and shower and thunderstorm evolution and possible heavy
rain threat tonight.

Details:

Low level jet forced moisture advection will only increase with time
this evening into the overnight, sending precipitable water values
to over an inch and a half. Isentropic upglide will become maximized
on the nose of this 50+ knot southwest low level jet, with pattern
recognition strongly supporting an expanding area of rain within
this forced ascent axis. While primary corridor of instability folds
south with time, just enough elevated instability looks to remain to
produce at least some embedded non-severe thunderstorms. Given
available moisture through a deep layer of the atmosphere and what
appears to be an appreciable warm cloud depth, we should see some
rather respectable rainfall rates...especially with any deeper
convective cores. Axis and orientation of low level jet argues for a
relatively narrow corridor of heavier rain potential. Still some
discrepancy where this axis will center itself, but trends generally
support tip of the mitt counties into eastern upper Michigan for
heaviest rain potential. Wouldn`t be terribly surprised to see an
inch or more where this axis lines up. Enough to produce some local
ponding on roads and in poor drainage areas, but otherwise no
significant impacts expected. Definitely a mild night, with most
areas not falling out of the 60s.

Front sweeps rapidly east of the area Wednesday morning, ending the
rain threat for most in the process. Post-frontal west synoptic flow
definitely supports the all to typical lake breeze convergence
corridor across central upper Michigan during the afternoon.
Lingering moisture looks more than adequate to potentially kick off
a few showers and perhaps isolated thunderstorms in this region
during the afternoon. Post-frontal cold air advection far from
impressive, helping temperatures recover into the upper 70s and
lower/middle 80s during the afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 259 PM EDT Tue Jul 2 2024

PATTERN SYNOPSIS/FORECAST:

Longwave troughing swinging through the area will keep the Great
Lakes Region active throughout the long-term. A shortwave trough
will track overhead late Thursday night into Friday, increasing
higher to mid level clouds ahead of a deepening low pressure system
that will track into the region for the weekend.

PRIMARY FORECAST CONCERNS:

- Independence Day: A shortwave trough will track overhead Thursday
evening. Looking at forecast soundings, it appears that the
atmosphere will be too dry in the lower levels to support rainfall
on Independence Day. However, clouds will build in later in the
evening in response to the aforementioned shortwave. Mainly Westerly
winds will create a downsloping component across Northeast lower,
making temperatures warmer in these areas (mid 80s) compared to
elsewhere in Northern Michigan (high 70s to low 80s).

- Weekend Precipitation Chances:  Attention then quickly turns to a
trough and its associated low pressure digging across the Midwest
and into the Great Lakes Region for Friday/ Saturday. Current
guidance continues to show moderate instability and a relatively
deep moisture fetch (PWATS above 1.2") into the region for this
weekend. The most favorable day for possible strong to severe?
storms to develop will be Friday, but showers are expected to
continue through most of the weekend and an embedded rumble of
thunder or two cannot be ruled out. Stay tuned as we continue to
fine tune these details!

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 119 PM EDT Tue Jul 2 2024

VFR conditions expected into this evening under high based
clouds and very light showers/sprinkles. More organized showers
expected to develop overnight, bringing a MVFR to IFR overcast
with them. May have a few rumbles of thunder as well, but
nothing too significant expected. Slow improvement as we head
through Wednesday morning. Low level wind shear tonight as
surface winds decrease. Winds look to become a bit gusty again
by later Wednesday morning.

&&

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

&&

$$

SHORT TERM...MSB
LONG TERM...NSC
AVIATION...MSB