072
FXUS63 KDTX 300759
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
359 AM EDT Tue Apr 30 2024

.KEY MESSAGES...

- Dry and slightly cooler today.

- Well above normal temperatures persist through the week.

- Mostly dry frontal passage on Wednesday with a better chance of
  precipitation arriving early Friday morning.

&&

.DISCUSSION...

The cold front moving through Michigan early this morning will usher
in a drier airmass with the 1.25 inch PWAT from the 00Z DTX RAOB
yesterday dropping to around a half inch by this afternoon. This will
bring a gradual decrease in cloud cover from west to east throughout
the morning. Cold advection will not be that strong with 850 mb
temperatures only falling a few degrees at 850 mb to 3-6 C by 18Z.
The lack of colder air and the clearing skies should allow the
improving insolation to achieve daytime highs into mid/upper 60s to
low 70s. Lower level westerly flow tops out around 25 knots in the
post frontal environment with afternoon mixing yielding a west wind
of 10 to 15 mph. Shortwave ridge will quickly pass over the region
this evening and tonight with mostly clear skies. Overnight lows dip
into the 40s for most of the CWA outside of the Detroit metro areas.

A shortwave at the nose of the upper jet will be driven out of the
central Plains and through the northern Great Lakes on Wednesday
while dragging a weak cold front through Michigan. Warm advection
ahead of the front for the afternoon will lead to an increase in
daytime high temperatures returning to the mid/upper 70s. Frontal
passage timing will be during the day, but overall lack of moisture
leans toward a mostly dry frontal passage. The main result will be an
increase in clouds. The better precipitation chances will be tied
closer to the low off to the north. Lower level dewpoints do increase
into the mid 50s, so wouldn`t be surprised if an isolated shower or
two is able to develop along the front. Confidence is too low to have
mention of PoPs at this time.

Ridging begins building over the Great Lakes Wednesday night with a
warm and dry airmass residing across Michigan through much of
Thursday. Well above normal temperatures will persist into the late
week period with daytime highs in the 70s common. Another mid level
circulation is set to pivot across the northern plains and through
the upper Midwest on Friday. Strong lower level jet will help drive
better moisture into the region ahead of larger scale ascent
associated with the cold front. Timing the onset of precipitation
leans toward late Thursday night/Friday morning as models have
trended a little faster with the frontal passage. This would likely
prevent much instability for being able to develop before arrival of
precipitation and limiting a more robust convective response. Lowered
PoPs in the Friday night time frame given this quicker frontal
passage trend. Limited cold air advection behind this front keeps
warm temperatures in the forecast to start the weekend.

&&

.MARINE...

With lighter winds early this morning and still some elevated
surface dew pts > than water temps, areas of fog will likely be
around Lake Huron through the morning hours as wind gusts
reside mainly below 20 knots throughout the day.

Another low pressure system looks to be tracking through Minnesota
and then into Lake Superior on Wednesday, with the cold front
swinging through the Central Great Lakes. Moisture looks lagging,
and the front appears to be weakening in the process. Thus, showers
and moderate winds will be hard to come by, with another surface
ridge then arriving Thursday morning.

&&

.PREV DISCUSSION...
Issued at 1142 PM EDT Mon Apr 29 2024

AVIATION...

The back edge of the light showers will be east of metro Detroit
around TAF issuance. Some thinning of the mid/high cloud deck
overhead may open the door to some low clouds and/or fog development.
This will be most probable at the metro Detroit TAFs where evening
rainfall has contributed to increased boundary layer moisture. A
weak cold front will then move across Se Mi in the 06Z to 09Z time
frame. A gradual wind shift to the west will occur with the passage
of this front. Subtle post frontal dry air advection should erode
any low clouds/fog toward daybreak. DIurnal heating and some remnant
low level moisture will contribute to a scattered to broken diurnal
cu field Tues afternoon.

For DTW/D21 Convection...The risk of lingering convection has ended
across the airspace. No thunderstorms are expected through the TAF
period.

DTW THRESHOLD PROBABILITIES...

* Moderate in ceilings aob 5000 feet tonight. Low on Tuesday.


&&

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

$$

DISCUSSION...AA
MARINE.......SF
AVIATION.....SC


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at www.weather.gov/detroit.