National Weather Service United States Department of Commerce


346
FXUS63 KDTX 181834
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
234 PM EDT Thu Jul 18 2024

.KEY MESSAGES...

* High pressure brings cooler, drier, and less humid conditions to
the region through the end of the workweek.

* Temperatures moderate over the weekend as high pressure departs,
followed by an approaching boundary Sunday which offers low-end
precipitation chances early next week.

&&

.DISCUSSION...

Benign pattern in place across the central Great Lakes with the
eastern edge of Midwestern surface high pressure firmly in place
overhead. Thermal troughing currently working across the region has
led to the generation of a healthy coverage of lake enhanced cumulus
this afternoon with northerly winds holding temperatures in the
lower 70s, some 10 degrees below normal. This cloud cover dissipates
tonight with the loss of diurnal heating setting up a clear, cool
night as lows fall into the low to mid 50s.

Surface high dominates local pattern through Saturday as it drifts
directly over the Great Lakes/northern Ohio Valley. Core of thermal
troughing slides to our east by late tonight supporting a gradual
moderation in temperatures as 850mb temps climb 1-2C each day
through this weekend. Highs likewise return to right around normal
in the mid 80s by the latter half of the weekend.

A weak baroclinic zone very slowly sags south through the Great
Lakes this weekend reaching northern lower MI by Sunday offering a
slight chance (~15%) for a stray shower over the Saginaw Valley or
Thumb during the afternoon. Boundary settles more into central lower
MI by Monday supporting a better chance for these areas to see
scattered showers and thunderstorms in the afternoon-evening. By
Tuesday this boundary looks to reside over southern lower MI as
attendant moisture pooled along said boundary pushes dewpoints well
into the mid 60s supporting scattered showers/storms across the area.

&&

.MARINE...

Expansive high pressure over the Midwest into the Great Lakes region
will lead to light winds (under 20 knots) right into early next
week. The next chance of showers and thunderstorms does not look to
arrive until Tuesday, with a low chance continuing through Thursday.

&&

.PREV DISCUSSION...
Issued at 104 PM EDT Thu Jul 18 2024

AVIATION...

Northerly flow today has advected moisture from Lake Huron into
southeast Michigan and helped sustain a scattered to broken cumulus
cloud deck this morning. Ceilings look to be at or around 5000 feet
before clouds dissipate this evening leaving clear skies. Winds
light and variable overnight before solidifying into westerly flow
tomorrow. Sky conditions tomorrow look to be similar to today. No
showers or storms are expected and a diurnal cumulus deck is
expected to develop around 4000 feet.

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

DTW THRESHOLD PROBABILITIES...

* Medium for ceiling at or below 5000 ft today. Low for tomorrow
afternoon.


&&

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

$$

DISCUSSION...KDK
MARINE.......sf
AVIATION.....BC


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