National Weather Service United States Department of Commerce


000
FXUS63 KDTX 262014
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
314 PM EST Wed Jan 26 2022

.DISCUSSION...

A mid level ridge and associated sfc high pressure overhead will
quickly advance toward the Mid Atlantic/Northeast tonight as a new
round of height falls overspreads the Upper Midwest/nrn Great Lakes.
These height falls are associated with a trough axis extending south
from a Hudson Bay polar low. The departure of the sfc high to the
east and approach of the associated cold front into the nrn Great
Lakes tonight will result in a strengthening low level south-
southwest gradient with 1-2k ft level winds forecast to increase to
30-40 knots. This and some increase in mid/high clouds during the
night will limit the degree of radiational cooling potential. Given
that the temps fell short of 20 this afternoon and the dry arctic
airmass extends into the Lower MS Valley, min temps tonight should
still drop into the single digits.

Sfc winds actually look to increase prior to daybreak Thurs as the
gradient increases. This will insure sub zero wind chill readings in
the morning. The SSW flow will drive daytime highs Thurs into the
20s. Model soundings suggest 20 to 30 knots in the shallow daytime
mixed layer, which will actually result in a rather blustery day.
There is respectable model agreement in a lead short wave impulse
advancing across srn Mi ahead of the main longer wavelength trough
and associated sfc cold front. System relative ascent along the 284-
288k surfaces will be quite good Thurs morning preceding this wave.
However, there will not be much depth to the moist ascent. With
residual low level dry air, not much other than flurries is expected
with this lead wave. A little better low level moisture is forecast
to accompany the passage of the sfc cold front across Se Mi late
Thurs afternoon/evening, likely aided by subtle moisture flux off
the lakes. This will support a chance for snow showers, with minimal
accumulations expected.

The passage of this front will deliver a reinforcing shot of arctic
air by Friday, supporting another day where temps struggle to break
20. There is reasonable model agreement in building sfc high pressure
across ern Ontario Friday, allowing the colder/more dense air across
Ontario to drive the mid Lake Huron thermal trough and convergent
lake band west toward the Michigan side of the lake. Several hi res
solutions bring this band into Port Huron by 12Z Fri with the latest
NAM/GFS holding the convergence over Port Huron through much of the
day. These situations are often difficult to forecast as a slightly
more northwest component to the sfc wind may very well keep the band
over Sarnia as opposed to Port Huron. While lake modified soundings
suggest inversion bases under 5000 feet, the moisture flux off the
lake is likely to support supersaturation with respect to ice in the
layer for good dendrites. So there seems to be a potential for very
localized accumulation snow. Given the uncertainty at this stage in
the forecast, high chance type pops will be introduced for Port
Huron attm.

Conditions will be cold and dry on Saturday as Se Mi will lie under
the mid level subsidence regime west of the explosive cyclogenesis
forecast to take hold off the coast of New England. A relatively
weak short wave/clipper system will provide a chance for light snow
on Sunday. The medium range model solutions remain suggestive of a
significant long wave pattern chance across NOAM next week which
will result in building heights across the ern US and a chance for
seasonably mild temperatures across the Great Lakes.

&&

.MARINE...

Broad area of high pressure now situated over the Ohio Valley loses
influence over the Great Lakes this afternoon as deep low pressure
moves toward Hudson Bay. Southwesterly flow increases through the
evening as a tightened gradient and respectable low level wind field
expand into the region and support gale force gusts of 35 to 40
knots, with a Gale Warning going into effect for the northern half
of Lake Huron tonight as a result. Arctic airmass combined with
gusty winds and waves will also pose a threat for heavy spreezing
spray, in which a Heavy Freezing Spray Warning is in effect for the
same timeframe. Frontal passage during the latter half of Thursday
will bring the next round of snow chances to the marine waters,
along with diminishing winds and waves to end the work week.

&&

.PREV DISCUSSION...
Issued at 1148 AM EST Wed Jan 26 2022

AVIATION...

Low-level flow will back from WSW to SW this afternoon which will
pull the better Lake Michigan lake moisture inland, aiding in the
production of some SCT boundary layer clouds when coupled with
diurnal heating. Some of the currently established SCT/BKN lake
clouds currently parked over western Michigan will try to advect
northeast towards KFNT/KMBS late this evening, which may bring a
brief period of BKN coverage, although given the dry conditions in
place, this better coverage may break apart before reaching the
terminals. Otherwise, high clouds start to move in overnight in
response to a stronger southwest gradient overnight, drawing in
better moisture from the southern US.

DTW THRESHOLD PROBABILITIES...

* None


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning from 10 PM this evening to 5 AM EST Thursday for
LHZ361.

Heavy Freezing Spray Warning from 10 PM this evening to 4 PM EST
Thursday for LHZ362-363-462.

Gale Warning from 10 PM this evening to 4 PM EST Thursday for
LHZ362-363-462.

Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

DISCUSSION...SC
MARINE.......MV
AVIATION.....AM


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