597
FXUS63 KDTX 301644
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1244 PM EDT Tue Apr 30 2024

.KEY MESSAGES...

- Dry and slightly cooler today.

- Well above normal temperatures remain through the week.

- Likely a dry frontal passage on Wednesday with the next chance
  of precipitation arriving early Friday morning.

&&

.AVIATION...

Lower VFR/MVFR stratus/strato-cu north of I-69 will shift out of the
area early this evening with generally clear skies into tonight. To
the south, just a few cu may pop up this afternoon. West winds 10-15
knots will gusts to 20+ knots at times in decent mixing, then weaken
considerably overnight within high pressure bubble. Gusty southwest
winds will develop again Wednesday as the next low pressure system
once again tracks well to the north. VFR conditions will prevail as
increased low level moisture only aids in scattered diurnal cumulus
development by midday.

For DTW/D21 Convection...Thunderstorms are not expected through the
TAF period.

DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 1040 AM EDT Tue Apr 30 2024

UPDATE...

Completed a quick grid edit to update sky trends for the remainder of
the day. Main change was to lower sky fraction earlier across the
southern cwa based on satellite trends. With no current cloud over
southwest Lower Michigan, skies along and south of I 69 are expected
to remain clear. Blanket of stratocumulus will continue to
build/push into the northern Thumb in response to moisture advection
and cooling between 2.5 and 5.0 kft agl.

PREV DISCUSSION...
Issued at 359 AM EDT Tue Apr 30 2024

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.

&&

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

$$

AVIATION.....DG
UPDATE.......CB
DISCUSSION...AA
MARINE.......SF


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