065
FXUS63 KDTX 020340
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1140 PM EDT Mon Jul 1 2024

.KEY MESSAGES...

- Seasonable conditions Tuesday as clouds thicken through the day.

- Potential for showers to develop Tuesday night, with isolated
  thunderstorms. Chance of showers and thunderstorms will continue
  into Wednesday as conditions turn more humid.

&&

.AVIATION...

High pressure will continue to provide VFR conditions as it shifts
off to the east overnight into Tuesday. As this occurs, mid to upper
level moisture will increase aoa 15kft. Light east/southeast winds
tonight will become more south-southeast on Tuesday with wind speeds
peaking around 10 knots (a bit stronger for MBS?) by midday.

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

DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 400 PM EDT Mon Jul 1 2024

DISCUSSION...

Lower column anticyclone well-established over the Great Lakes this
afternoon ensures a subsident airmass through the rest of today
while cooler Canadian air filters in from the northeast. Mainly
clear skies prevail, as expected, given the uncharacteristically dry
01.12Z KDTX RAOB (PWAT of 0.36 inches) which revealed a 40C dewpoint
depression at 6 kft AGL (800 mb) and mean mid-level lapse rates of
only 5 C/km. Synoptically, the mid-/upper-level ridge axis still
remains west of The Mississippi, but will begin to dislodge eastward
late this evening and overnight as a longwave trough deepens over
the Mountain West. Cloud fraction aloft will increase accordingly as
high cirrus/anvil debris eventually spill downstream of on-going
convection. Light surface winds veer southeasterly as the surface
high pressure center exits toward The Northeast, ushering in more
seasonable air.

Clouds thicken Tuesday as a warm front lifts into Lower Michigan
marked by a jump in H8 temps into the mid-upper teens (Celsius)
amidst strengthening return flow. Dewpoints also respond, steadily
rising into the mid 50s to near 60F by dusk while mean low-level
moisture profiles play catch-up to stronger ThetaE advection aloft.
Temperatures peak near 80F (+/- 3F). Chance of showers and
thunderstorms increases Tuesday night as a cold front approaches
from the west. The longwave state features a parent trough residing
over the Canadian Prairies and Montana while a speed max transits
the interface between the aforementioned trough and the controlling
ridge over ArkLaTex. Poleward confluent flow intensifies across
central CONUS as the flanking front migrates east, but uncertainty
exists regarding the rate of saturation and how long it takes for
the anticyclonic gyre to dislodge, locally. Latest PoP adjustments
are generally in-line with inherited values which reserves broader
coverage of shower/storm activity until Wednesday.

Bulk of upstream/inbound convective activity Wednesday morning will
more likely be located over western Lower as the front slowly works
through the area and degrades. Main window for CVA expected around
the 12-18Z timeframe while surface dewpoints break into the 70s.
Best shear remains over the north half of the CWA while the better
instability should stay over the south. Lapse rates are rather poor
per the GFS and only marginally better per the humidity-biased NAM.
Low confidence exists with the coverage and intensity of afternoon
convection.

Active westerlies in-place just south of the MI/OH line Thursday
should keep conditions mainly dry. Still warm and a bit humid
through the rest of the work week. Next shortwave digs across the
Dakotas Thursday evening sparking cyclogenesis over the Midwest.
Additional showers and storms are possible Friday.

MARINE...

A strong high pressure center is now centered over the Great Lakes
which will continue to promote dry weather and light winds. High
pressure will continue to move east through the day, centering over
New England by Tuesday afternoon. This will veer wind direction to
the southeast by late tonight. Wind speeds and gust potential will
increase slightly on Tuesday with the departure of high pressure,
with gust potential of around 20 to 25 knots across Lake Huron. A
cold front is then expected to move over the Great Lakes on
Wednesday, which will further back wind direction to the southwest
as well as bring shower and thunderstorm potential. The southwest
fetch across the Saginaw Bay will bring a window to see gusts around
25 knots Wednesday afternoon and evening. Small Craft Advisories may
be needed. A weak area of high pressure will build in Thursday,
returning lighter winds to the Great Lakes.

&&

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

$$

AVIATION.....DG
DISCUSSION...KGK
MARINE.......AM


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