902
FXUS63 KDTX 130920
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
520 AM EDT Tue Aug 13 2024

.KEY MESSAGES...

- Seasonable temperatures today with mainly dry conditions outside
  of an isolated shower.

- A bit warmer Wednesday and Thursday with dry conditions.

- Rain chances increase Thursday night and Friday and
  continue through the weekend.

&&

.AVIATION...

Light and variable winds and mostly clear skies expected through the
taf period. Modest increase in VFR clouds expected this afternoon,
with brief cigs possible, especially over southern tafs where there
is also a very low chance of a passing showers. There is fog
potential tonight, but confidence is low and will just include MVFR
restriction for now.

For DTW/D21 Convection...Thunderstorms are not expected.

DTW THRESHOLD PROBABILITIES...

*  Low for cigs at or below 5000 ft this afternoon.

&&

.PREV DISCUSSION...
Issued at 332 AM EDT Tue Aug 13 2024

DISCUSSION...

Larger scale pattern remains defined by upper level northwest flow
atop a loosely organized, elongated region of high pressure.
Shortwave energy accelerating through the mean flow set to arrive
this morning, a touch sooner than model guidance projected over
recent days. Little evidence per observational trends or hi res
solutions for the uptick in dcva to afford a greater window for
convective development early today, given the noted stability still
held throughout the column as this poorly timed trough passage fails
to capitalize on the heating cycle. Lack of meaningful instability
still evident into the afternoon, held back by limited moisture
quality within a modestly mixed profile. This offers simply a very
low potential /less than 20 percent/ for a smattering of showers to
emerge 20z-00z, perhaps anchored by lake breeze interaction with any
localized differential heating zones. Seasonable temperatures
persist.

Higher magnitude upper ridging anchored over the midwest today will
ease into the region over the next 36 hours. Conditions governed by
low to mid level ridging both Wednesday and Wed night lends to
benign weather conditions under mostly clear skies. This translates
into a modest warming trend this period under a combination of
building upper heights and full diabatic heating potential. This
brings high temps of low to mid 80s, with a bump upward in humidity.
Next round of stronger height falls underway by this time across the
plains, setting the stage for greater moisture transport to emerge
within a broadening corridor of warm air advection immediately
downstream. Larger scale ridging likely to maintain a strong
influence into Thursday, acting as an initial deterrent for any lead
shortwave energy to organize a greater mid level response as higher
level moisture increases with time. Mostly cloudy conditions favored
for the daylight period, with limited precip potential until closer
to sunset.

Plume of higher quality theta-e arrives Thursday night along an
advancing warm front attendant to stacked low pressure system
centered over north-central Wisconsin. Diminishing mid level
stability to capitalize on supportive large scale ascent to bring a
higher probability of showers and embedded thunderstorms this
period. There remains some uncertainty regarding downstream pace and
positioning of the larger scale features, meaning these conditions
may linger and/or focus more into Friday depending on timing of the
trailing cold/occluding front. NBM maintains a broader outlook for
this window in offering higher end precip chances both periods so
addition refinement likely. Upper low remains a fixture into next
weekend as it slowly migrates across the great lakes. The warm
season mid level cyclonic flow lends to unsettled conditions, with a
particular focus on the afternoon and evening as lapse rates peak
beneath the cold pool and engage a very moist profile. Temperatures
likely edged just on the cooler side of average, with a degree of
variability each day depending on precip coverage.

MARINE...

High pressure holds over the region through Wednesday maintaining
light and variable winds, minimal waves, and dry conditions.
Southeasterly winds strengthen by late Thursday as upper Midwest low
pressure reaches the Great Lakes. This system brings the next
chances for showers and storms as well as moderate (~15-20kt)
southeast winds to close out the week.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....SF
DISCUSSION...MR
MARINE.......KDK


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