681
FXUS63 KDTX 211658
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1158 AM EST Fri Feb 21 2025

.KEY MESSAGES...

- Slow warming trend through the weekend into early next week, with
high temperatures back above freezing on Sunday, and at or above 40
degrees Monday through Wednesday.

- Mostly dry over the weekend, with a better chance of precipitation
Monday-Tuesday, which looks to be mostly in the form of rain.

&&

.AVIATION...

Drier northwest flow will continue to gain traction this afternoon,
affording a gradual decline in coverage of lingering stratocumulus.
Scattered to briefly brokent coverage will persist through the
latter half of the day, before a greater signal of clearing emerges
with loss of daytime heating this evening. This clearing condition
expected to hold tonight given retention of a dry and stable
environment. Prevailing west-northwest wind becoming southwest
tonight.

.DTW THRESHOLD PROBABILITIES...

* Low in ceilings aob 5000 feet this afternoon.

&&

.PREV DISCUSSION...
Issued at 241 AM EST Fri Feb 21 2025

DISCUSSION...

Gradual warm up carrying into early next week, with temps reaching
aoa 40 degrees as the jet stream hangs around the far northern
Conus.

Low clouds in place across Lower Michigan early this morning,
helping to keep temperatures elevated in the lower 20s/around 20 at
the present time. There is even scattered flurries around with the
Lake Superior-Michigan connection as the inversion height/saturation
is embedded in the DGZ. Shortwave ridging building into the Central
Great Lakes will lead to further warming and drying in the mid
levels, with the subsidence inversion lowering to around 3000 feet
late this morning. Still may not be low enough to dissipate the low
clouds as westerly low level flow off Lake Michigan continues.
NAM/RAP/HRRR soundings all hang onto clouds for the most part, and
will err on the pessimistic/mostly cloudy side with temps holding in
upper 20s.

Moisture starved mid-upper level wave over Manitoba will attempt to
slow the warm up, as it tracks through northern Lower Michigan
around midnight, but strengthening low level southwest flow will
modify 850 MB temps to mid negative single numbers by Saturday
afternoon, with 925 MB temps reaching around -7 C, supportive of
high temps around 30 degrees.

Modest height rises and persistent low level southwest winds, albeit
at a diminished speed, for the second half of the weekend should
lead to max temps well into the 30s for Sunday.  Left exit region of
~120 knot jet looks to be spreading in for Sunday evening/night,
potentially triggering a little light snow, mainly north of I-69.
The main upper level wave/shortwave looks to be tracking through
lower Michigan on Monday, supported by UKMET/GFS/Euro, which brings
a chance of rain, as max temp in the low levels comfortably exceeds
3 C.

Yet another fast moving upper level wave tracking through the
Midwest Monday night and arriving by Tuesday morning. NBM grids
suggest it will still be just warm enough for all liquid precip, but
thermal profiles do look to become borderline as the system is
progged to deepen, potentially becoming cold enough for wet snow, as
1000-500 MB thicknesses drop below 540 DAM. 00z Euro maintaining
surfaced dew pts around 32 degrees with 925 MB temps of 1-2 C.
Regardless, qpf progged to be under a quarter of an inch, as euro
ensembles only indicating a 30-40 percent chance of reaching and
exceeding a tenth of an inch.

MARINE...

Northwest wind gradually eases through the morning as a ridge of
high pressure expands into the area from the southwest. Weaker winds
will back from northwest to southwest over the course of the day
then strengthen tonight as a low-level jet advances across the
central Great Lakes. Stability below this jet prevents the full
extent of the 35 to 40 kt core from reaching the surface, but enough
mixing in the near-surface layer should allow for 25 to 30 knot
gusts to develop across Lake Huron on Saturday. A period of 35 kt
gales cannot be ruled out for central portions of the lake in the
afternoon but current guidance suggests less than a 30% probability
for this to occur. The jet passes east by late Saturday evening,
causing winds to subside. Moderate southwest wind persists through
Sunday then shifts more southerly in advance of a clipper system set
to track through the northern Lakes on Monday. An active but milder
pattern is in store for early next week with several additional low
pressure systems likely to affect the area. Low confidence exists
on timing and strength of these systems.

&&

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

$$

AVIATION.....MR
DISCUSSION...SF
MARINE.......TF

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