536
FXUS63 KDTX 011900
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
300 PM EDT Tue Jul 1 2025

.KEY MESSAGES...

- There is a chance of thunderstorms Wednesday afternoon and evening.
  There is a marginal (isolated) risk of severe storms north of an
  Ann Arbor to Detroit line.

- Hotter and more humid conditions are forecast Friday through
Sunday.

- There is a chance of thunderstorms this weekend.

&&

.DISCUSSION...

Mid level anticyclonic flow has dominated Lower Mi today. This and
ongoing low level dry air advection has sustained ample sunshine
today with just scattered diurnal clouds. Low to mid level
anticylonic flow will persist across srn Lower Mi tonight, allowing
respectable nocturnal cooling, supportive of nighttime lows mainly
in the 60s.

An upper low now over northern Manitoba will advance across nrn
Ontario tonight into Wednesday night, driving a cold front south
across the northern lakes. General consensus among the 12Z models is
to bring this cold front into the thumb and Saginaw Valley region
Wednesday evening. A weak mid level short wave impulse, likely
enhanced to a degree within nocturnal convection tonight, is
forecast to track across Lower Mi late Wednesday. This may help
enhance a convective response, particularly along the cold front.
Model soundings through early afternoon show a mid level cap in
place. Gradual mid level cooling, particularly across the north,
will erode this cap during the course of the afternoon. Most of the
CAMs solutions continue to suggest scattered to numerous coverage of
convection across the Saginaw Valley and thumb region Wed
afternoon/evening, with coverage/chances decreasing south toward the
I-94 corridor where stronger capping and less forcing will be more
of a limiting factor. A marginal (isolated) severe risk remains
across most of Se MI. SB Cape has the potential to reach 2k J/kg.
The northern sections of the forecast area have some potential for a
little better convective organization as 0-6 km bulk shear values
are forecast around 25 knots. Strong winds due to wet microbursts
will be the main severe hazard.

The aforementioned cold front is forecast to linger over Se Mi as a
stationary front through the day Thursday. Model soundings show a
little stronger mid level cap. This and broad mid level confluence
and rising heights will limit convection potential to just isolated
along the front. Similar thermal profiles will again support highs
into the 80s. While some moisture pooling may occur along the sfc
front, overall humidity values will remain relatively low.

Some degree of upscale convective growth is possible Thurs night/Fri
morning across the western Great Lakes along the nose of enhanced
low level inflow. There is some potential for a convective release
into Lower Mi on Friday amidst building mid level heights into the
Upper Mississippi Valley. This may be enhanced by an influx of lower
70 sfc dewpoints into srn Mi resulting in moderate daytime
instability. Heat and humidity are forecast to persist into the
weekend, with at least a chance of convection each day.

&&

.MARINE...

A ridge of high pressure extends from the Midwest into the Great
Lakes, promoting stable conditions and light westerly wind through
tonight into Wednesday. A weak cold front then sinks across the
region late Wednesday, bringing scattered showers and storms mainly
focused across Lake Huron. Isolated storms will be capable of
producing winds in excess of 40 kt and hail. Post-frontal wind
organizes out of the northwest on Thursday, remaining light. High
pressure builds directly across the region Thursday night to
maintain light wind and waves into Friday. A warm front then lifts
across the region on Saturday, setting up a breezy southwest flow
that brings in warmer, more humid, and unsettled conditions for the
weekend.

&&

.PREV DISCUSSION...
Issued at 157 PM EDT Tue Jul 1 2025

AVIATION...

VFR through the forecast as high pressure and drier northwesterly
flow reside over the region. Typical summertime diurnal cu field
around 4-6kft this afternoon should clear out tonight. Winds will
gust into the teens today at time before relaxing tonight. Lighter
wind field heading into tomorrow afternoon with another round of VFR
cu.

For DTW/D21 Convection...No thunderstorms expected today or tonight.

 THRESHOLD PROBABILITIES...

* Low for cigs aob 5kft this afternoon and early evening.


&&

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

$$

DISCUSSION...SC
MARINE.......TF
AVIATION.....DRK


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