Whitmore Lake, Michigan Weather Forecast Discussion

242
FXUS63 KDTX 121921
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
321 PM EDT Fri Sep 12 2025
.KEY MESSAGES...
- Low chance to chance (15-20%) for isolated to scattered showers
tomorrow morning into early afternoon.
- Much above normal highs with continuing dry weather next week.
&&
.DISCUSSION...
Western periphery of high pressure and build up of a 586dam ridge
brings another round of dry weather and mostly sunny skies.  Ongoing
showers and convection over northern Minnesota into Wisconsin will
wane leading into the night as it targets the U.P. and northern lower
Michigan. A secondary response just south of the ongoing activity,
fueled by unbalanced flow on the nose of a jet, which will strengthen
tonight, will sustain adequate moisture transport for nocturnal
convection. A convectively enhanced shortwave will sustain activity
into Michigan despite the disconnect with instability. Showers and
any embedded storms will be entering a non-conducive environment for
sustained activity with poor mid-level lapse rates and very little to
no elevated instability. The expectation is for this feature to path
into SE MI through tomorrow afternoon and early evening, but for
coverage to wane as it moves across the cwa. Will continue to
maintain around a 15-20% chance for PoP, favoring more isolated to
scattered coverage of showers, with a very low chance for an embedded
thunderstorm. Otherwise, mid to high based altostratus to cirrus
will fill in through the day until the shortwave has cleared.
A deep trough extending through the western CONUS will amplify
ridging downstream into the Great Lakes starting Sunday and into
early next week. A rex block pattern then forms and holds through
the midweek period, again with high pressure holding over the Great
Lakes. This will bring yet another round of extended dry weather and
above normal temperatures. There is moderate to high confidence to
see highs aoa 80 degrees through the entire forecasting period,
outside of the lakeshore and inland Thumb region, where weak
gradient flow will allow a lake breeze to develop near peak heating
hours. This will moderate high temperatures by several degrees
holding temperatures just shy of the 80 degree mark.
&&
.MARINE...
Departing high pressure has led to light southeast flow and dry
weather across the Great Lakes this afternoon. Glancing influence
from Hudson Bay low pressure Saturday and a cold front Saturday
night lead to low coverage of light showers throughout the day and
evening hours. High pressure then builds across Ontario Sunday into
early next week, while upper level ridging slides in from the
Plains. This brings a seasonably warm airmass into the Great Lakes,
while reinforcing dry and favorable marine conditions.
&&
.PREV DISCUSSION...
Issued at 132 PM EDT Fri Sep 12 2025
AVIATION...
High pressure centered over southern Quebec and the eastern Great
Lakes continues to dominate the weather through the period. This
maintains stable, VFR conditions with a diurnal cu field based
around 5 to 6 kft and light southerly wind. Boundary layer cloud
dissipates with the loss of daytime heating, then mid and upper
clouds fill in overnight into Saturday morning ahead of an upper
disturbance dropping into the western Great Lakes. A weak southerly
gradient wind is expected to hold through the night which should
help keep the moist marine layer offshore, mitigating fog concerns
overnight. The upper disturbance will bring potential for late
morning showers, but confidence remains low for this activity to
reach southeast MI as low-level dry air holds in place.
For DTW/D21 Convection... Thunderstorms are not anticipated through
Saturday.
THRESHOLD PROBABILITIES...
* None.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
DISCUSSION...AM
MARINE.......MV
AVIATION.....TF
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NWS DTX Office Area Forecast Discussion