944
FXUS63 KDTX 070343
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1143 PM EDT Tue May 6 2025

.KEY MESSAGES...

- Showers decrease in coverage today with a few additional pop-up
showers/storms possible this evening.

- A stray shower or two possible Wednesday night, then mainly dry
Thursday through Sunday.

- Notable warm-up this weekend into early next week with highs in
the mid to upper 70s.

&&

.AVIATION...

While there has been some clearing of the MVFR and higher based
clouds this evening, ample low level moisture may lead to low
stratus and fog development overnight into early Wed morning. Model
soundings and probabilistic guidance is supportive of IFR and LIFR
conditions developing. With a light gradient atop the shallow
nocturnal stable layer, the TAFS will remain more favorable of a low
stratus deck at this time. A push of drier air from the northwest
and the onset of daytime heating is expected to quickly erode any
morning low clouds in the 12 to 15Z time frame.

For DTW/D21 Convection... No convection is forecast through the TAF
period.

THRESHOLD PROBABILITIES...

* Medium in ceilings aob 5000 feet tonight through Wed morning.

* Low for ceiling and/or visibility below 200 ft or 1/2 SM late
  tonight and early Wed morning.

&&

.PREV DISCUSSION...
Issued at 300 PM EDT Tue May 6 2025

DISCUSSION...

Area of continued deformation showers within the northwest quadrant
of a persistent deep-layer low pressure system drifts westward this
evening with decreasing rainfall intensity and coverage. Monitoring
a secondary flare-up of north-south oriented convective activity
along a convergence axis featuring some degree of destabilization
and vorticity pooling aloft. Any storm development is expected to
remain pulsey and sub-severe with mainly dry conditions settling in
by 10 PM. The mature low then spins eastward tonight, tracking along
the southern shores of the eastern Great Lakes as short wavelength
mid-level ridging drops in from the Upper Midwest, south of the
lower column (and surface) anticyclonic circulation. Mid- and upper-
level drying precedes stubborn near-surface saturation, thus
wouldn`t be overly surprised to see some drizzle overnight.

Temperatures trend upwards Wednesday with decreasing cloud cover.
Mixed model signal as to when morning stratiform clouds finally
dissipate, but should be a period of mostly clear skies with patches
of diurnal cumulus popping up during the afternoon. Surface flow
will be rather weak, veering from northwest to northeast with a cold
frontal passage. This leads to gradient in high temperatures from
south to north, where locations south of M-59 break the 70F mark
while areas further north top out in the 60s. 850 mb temperatures
fall from near 10C to the low single digits into Thursday morning.
Starting to get more membership on-board with some FGEN activating a
discontinuous line of scattered light showers/drizzle along the
frontal slope late Wednesday night into Thursday morning once the it
progresses into far southern Lower. Pre-frontal moisture pooling,
mixed with residual low-level ThetaE will be marginal which lends
minimal QPF with this activity, but could still wring out a
hundreths or two of precipitation. Added some entry-level PoPs
between 06Z and 12Z Thursday. Post-frontal northeast flow promotes
cold advection into the state Thursday with parts of The Thumb
struggling to break out of the 50s in spite of ample sunshine.
Higher amplitude ridging approaches from the west Thursday and
Friday as a Rex Block attempts to organize over the Missouri River
Basin. This ensures one last day of cool to near-normal temperatures
on Friday before broader ridging spreads a milder airmass in from
Out West.

MARINE...

Large area of low pressure over the Central Great Lakes this
afternoon will slowly exit east tonight. Modifying airmass will
promote light winds into tomorrow morning. However, a cold front
will be sinking south through the day, with post frontal northeast
winds increasing tomorrow afternoon. With the differential water/land
heating during the day tomorrow, wind gusts to around 25 knots are
expected to develop over Saginaw Bay, and will be issuing a small
craft advisory. 850 MB temps lowering to near zero Wednesday night
over Lake Huron will only enhance the northeast winds as the low
level stability decreases, and small craft advisories will be
carried right through Thursday and likely will have to be expanded
to cover the rest of the nearshore waters of Lake Huron nearshore.
Prolong northeast fetch should also result in waves building at or
above 4 feet across the southern Lake Huron Basin. Large area of
high pressure building into the western Great Lakes will promote
light winds Thursday night into Friday however.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from noon Wednesday to 10 PM EDT Thursday for
     LHZ421-422.

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

$$

AVIATION.....SC
DISCUSSION...KGK
MARINE.......SF


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