444
FXUS63 KDTX 040738
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
338 AM EDT Tue Jun 4 2024

.KEY MESSAGES...

- Temperatures warm up today with highs in the middle to upper 80s.

- Showers and some thunderstorms likely Wednesday as a cold front
sweeps across the area. Some of the strongs may be strong to severe.

- Pattern shift for the latter half of the week brings below normal
temperatures through at least the end of the week along with
periodic chances of rain.

&&

.DISCUSSION...

Strong mid to upper level ridging with an anticyclonic trajectory
influence will result in dry weather for today. Forecast soundings
have been consistent in a relatively dry low column resulting in a
well mixed boundary layer. Highs today are forecasted to reach the
middle to upper 80s.

An anomalously strong, for late June, +120 knot upper level jet
streak will nose into Southeast Michigan midday Wednesday. A strong
lobe of planetary vorticity is forecasted to turn strongly to a
negative tilt over the western/central Great Lakes during the
afternoon. The main question for the Wednesday period remains what
sort of destabilization will occur under the specter of cloud cover.
The ECMWF and extended HRRR solutions have suggested some elevated
activity between 12-15Z lifting northeastward through the cwa in
response to a secondary warm front. The building consensus, however,
including the 3km NAM, MPAS solutions, and WRF-ARW runs, has been to
delay the more active convective response to 17-23Z as a 700mb
jetlet lifts into the area. The mass response to the inbound mid to
upper level kinematics should sharpen and dewpoint gradient/cold
front that will approach from the west during the early afternoon.
Survey of forecast soundings suggests MLCAPES of around 1000 J/kg
possible with 0-6km bulk shear of roughly 30 knots after the arrival
of the 700 mb jet. Environmental wind profile shows a largely
unidirectional wind profile in the soundings and the UVV signal
favoring storm motions parallel to the shear vector. Conditional to
surface based instability developing Wednesday afternoon, multicell
storm mode could result in a potential for damaging wind gusts to 60
mph and hail diameter to 1 inch. The latest Swody2 has included
Southeast Michigan in a Marginal designation for severe weather.

A strong closed upper level low pressure system is then forecasted
to take residence over the entirety of the Great Lakes Thursday
through the upcoming weekend. Various trough axes and lobes of
potential vorticity will undoubtedly rotate around the closed
circulation bringing periodic shower chances to the forecast area.
Its difficult to time each of shortwaves and accompanying
convergence axes with much lead time, but cool midlevel temperatures
will likely support precipitation chances during the daytime. The
forecast soundings from this vantage point do not rainouts for any
of the periods with plenty of dry with a good amount of dry air
progged in the lowest 4.0 kft agl and warmish midlevel temperatures
largely yielding static stability between 7.0-12.0 kft agl this
weekend. The guidance has nothing more than slight chance to low
chance this weekend. The temperature forecast will likely remain in
flux as increasing certainty in clouds for any of the daytime
periods will necessitate a lowering of daytime temperatures. The
current forecast is below normal daytime temperatures Friday, near
average this weekend.

&&

.MARINE...

High pressure moves out today ahead of a warm front moving across
the Great Lakes region. Chances for showers are possible, mainly
over the northern part of Lake Huron. Gentle southeasterly winds
stay intact until Wednesday, in which a cold front tied to the same
low pressure moves across the region. Frontal passage veers winds to
the southwest and brings further chances for showers and storms.
Wind speeds at the surface increase slightly to upwards of 15 knots,
but strong low level flow may provide chances for a 25-30 knot gust
to occasionally mix down. Large upper level trough keeps surface low
pressure in place for Thursday and beyond, with chances for showers
through the weekend.

&&

.PREV DISCUSSION...
Issued at 1213 AM EDT Tue Jun 4 2024

AVIATION...

Rain has held north of MBS early tonight with VFR conditions
expected through the bulk of tonight. There will be a period from
about 09Z to around sunrise for fog to develop, mainly across PTK
and metro terminals. The high surface moisture remains in place
supporting the fog potential. However, gradient flow looks to stay
at about 5 knots and good degree of high clouds is filtering into
southeast Michigan downstream of the showers to the north. This will
greatly limit fog development, but MVFR visibility restrictions will
be possible. Any fog will lift shortly after sunrise with VFR
prevailing through remainder of the day. Winds today will be up to
around 10 knots or less and out of the south- southeast. Chances for
rain and possible thunderstorms arrive return late tonight, but will
be more likely beyond this TAF period on Wednesday

For DTW/D21 Convection...Low chance for thunderstorms arrive after
06Z. Greatest chance for thunder will be after 12Z Wednesday.

DTW THRESHOLD PROBABILITIES...

* Low for cigs/vsby falling below 200 ft and/or 1/2 SM near sunrise
  this morning.


&&

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

$$

DISCUSSION...CB
MARINE.......BC
AVIATION.....AA


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.