Expert Forecast Opinion

980
FXUS63 KDTX 080915
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
515 AM EDT Tue Oct 8 2024

.KEY MESSAGES...

- Quiet weather through the rest of the work week with temperatures
near normal.

- There is a chance of frost Tuesday night, Wednesday night and
Thursday night particularly away from Lake Huron.

&&

.AVIATION...

Scattered high cloud streams into the region today keeping VFR
conditions prevailing. Limited diurnal cumulus around 5kft is
possible this afternoon however not expecting much more than FEW to
SCT coverage given the modest low level moisture. Weak morning winds
increase by late morning as daytime mixing taps into stronger flow
aloft to support NW gusts up to around 20kts through the afternoon
period. The loss of mixing after sunset beneath high pressure
supports light (5kt or less) wind tonight.

For DTW/D21 Convection... No thunderstorms expected.

DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 311 AM EDT Tue Oct 8 2024

DISCUSSION...

Strong confluence aloft has resulted in deep tropospheric subsidence
region wide with a steady supply of dry air. DTX raob and nwp
initializations suggest strong static stability residing between 7.0
and 20.0 kft agl with a dry mixed layer from the surface to 5.0 kft
agl. Really very little to support cloud or even some surface based
shallow fog at daybreak this morning. An inflection to the upper
level jet axis and composite trough feature will dig through Lower
Michigan this afternoon and evening. Models have been very
consistent in suggesting a lobe of absolute vorticity and some minor
increase in favorable upper level jet dynamics for lift through the
Lake Huron vicinity offshore of the Thumb between 21-03Z. Moisture
depth is expected to be very shallow centered at 800mb. Will likely
be a little virga on radar but given the depth of dry air at the
surface will leave any slight chance PoPs limited to the tip of the
Thumb.

Surface high pressure will then increasingly build over Southeast
Michigan Wednesday and Thursday. The only weather item to speak of
is Frost potential Wednesday and Thursday morning. The upper level
jet axis and kinematic field will remain overhead Tuesday
night/Wednesday morning which should keep enough of a northwest
gradient wind in place to allow for total decoupling. Will continue
to lean on the EC-AIFS for temperatures and favor upper 30s for many
areas Wednesday morning. Do think Thursday morning will be cooler
for many more locations as the heart of the surface high pressure
will expand into Southeast Michigan from the north. The exception
will likely be in the Thumb and near Lake Huron as models show good
potential for due northerly flow. In fact, will need to monitor for
possible rogue lake effect showers in Huron and Sanilac counties at
daybreak Thursday.

Quiet, dry weather is anticipated Thursday and Friday before
geopotential heights lower fairly dramatically for the weekend. The
feature of interest for the much of the weekend will be a relatively
dry cold front that is expected to settle southward through
Southeast Michigan. Timing is suspect, but current indications
suggest Saturday morning before stalling out invof northern IN/OH
for late Saturday. Deep upper level troughing is then possible for
the end of the weekend along with a potential for a duration of deep
frontogenesis. Confidence is very low on timing and location of the
best wave response.

MARINE...

Cool northwesterly flow continues to progress over the warmer lake
waters of Lake Huron which will sustain elevated mixing depths and
over lake instability. The result will be the continuation breezy
conditions across Lake Huron, noted by sustained northwest winds
around 20 knots, gusting around 25 knots. Sporadic gusts upwards to
30 knots cannot be ruled out through tomorrow. The boost in
instability will also support lake effect rain showers and a very
low-end chance for a waterspout over Lake Huron today and tomorrow.

The northwest flow will also result in elevated wave heights across
the Thumb, but current guidance holds the more elevated wave action
just offshore for today. The exception will be tomorrow afternoon
and evening, where slight veering of wind direction acts to build up
wave heights near four feet across portions of the outer Saginaw Bay
through Harbor Beach. A short-duration Small Craft Advisory may be
needed. High pressure builds in early Thursday morning, which will
decrease wind speeds and gust potential.

&&

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

$$

AVIATION.....KDK
DISCUSSION...CB
MARINE.......AM


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