856
FXUS63 KDTX 300931
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
531 AM EDT Sun Jun 30 2024

.KEY MESSAGES...

- Cooler and less humid conditions to finish the weekend period.

- High pressure over the area maintains dry conditions and
seasonable temperatures early next week.

- Warmer and more humid conditions arrive midweek, with increasing
potential for showers and thunderstorms.

&&

.AVIATION...

Cold front is dropping through the terminal corridor at time of
discussion setting up breezier northwest winds (gusts around 20kts)
in its wake- these likely persist through the daylight hours today.
MVFR ceilings currently across northern lower MI expand into SE MI
this morning as cooler airmass settles in. Minimal lifting is
expected though with drier air gradually working into the region,
cloud cover should scatter out by evening with clear skies possible
overnight into Monday.

For DTW/D21 Convection...Thunderstorms are not expected during the
upcoming forecast.

DTW THRESHOLD PROBABILITIES...

*  High in ceilings aob 5kft this morning into the early afternoon,
   medium to low by late this afternoon-evening.

&&

.PREV DISCUSSION...
Issued at 353 AM EDT Sun Jun 30 2024

DISCUSSION...

Mid level wave lifting across the northern great lakes early this
morning, affording modest height falls throughout the region with an
associated cold frontal passage ongoing locally. Effective
replacement of the existing moist airmass underway as low level flow
attains greater depth with time from a northerly trajectory. This
cooler/drier profile becomes entrenched to finish the weekend
period. Model consensus on projected highs lends confidence to a
rather muted overall diurnal temperature response by late June
standards. A diurnal boost to lapse rates beneath broad mid level
cylonic flow points to a more extensive stratocumulus field
developing, capping the heating potential somewhat and ultimately
parking temperatures in the upper 60s/lower 70s. A reasonable
radiational cooling environment governed by decreasing cloud
coverage and wind speed under building high pressure nets a low
temperature Monday morning near 10 degrees below average.

Confluent upper level northwest flow atop a 1025 mb surface high
ensures a stretch of deep layer stability within a very dry airmass,
affording benign weather to start the work week. Steady rise in the
geopotential height field as the weekend mid level trough
relinquishes control will bring an initial period of moderating
temperatures today. Full insolation potential offers an additional
boost, yielding pleasant conditions highs of mid 70s and low
humidity.

Pattern of warm air advection emerges Tuesday and Tuesday night as
southerly flow attains greater depth and strength within a broader
region of upper ridging. Shortwave energy cruising through the mean
flow offers focus for an initial period of moisture transport
upstream and corresponding convective expansion during this time.
Streamline trajectories suggest greater moisture advection will
primarily take aim across west/northwest lower Michigan throughout
the daylight period, although the eastward expanse of the elevated
moist plume lead edge could glance across the Saginaw valley. Higher
quality moisture will then accompany eastward expanding height falls
and the associated cold front boundary into the region overnight
Tuesday night and especially into Wednesday. Precipitation potential
will increase accordingly. Ill-defined forcing field overall at this
stage, with frontal timing/strength relative to the heating cycle
proving important for guiding the coverage and magnitude of any
convective response. 850 mb thermal ridge of +20c anchored locally
within the pre-frontal environment nets the warmest conditions of
the week.

MARINE...

High pressure moves in today and brings northwesterly flow of 20
knots or greater across parts of Lake Huron. Winds speeds and
directions will push wave heights above criteria for a Small Craft
Advisory to be issued for the nearshore zones of Lake Huron with the
exception of Inner Saginaw Bay. Small Craft Advisories will be in
effect from 7am to 10pm. There is also a high swim risk for Huron
County tomorrow, and a Beach Hazards statement is in effect from 8am
to 10pm tomorrow.

As the high pressure center moves overhead on Monday winds will calm
and dry conditions will prevail. Pressure gradient tightens once
again with the departure of the high on Tuesday leading to southerly
flow up to 20 knots. The next chances for showers and storms come
Tuesday evening as a low pressure system moves in.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through this evening for MIZ049.

Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-
     441>443.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....KDK
DISCUSSION...MR
MARINE.......BC


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