Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000
FXUS63 KDTX 310003
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
703 PM EST Mon Jan 30 2023

.AVIATION...

A more favorable period of aviation weather builds into the region
with high pressure tonight and Tuesday. The center of the surface
high does sink to our south which maintains a westerly low level wind
across Lower MI and potential for clouds and flurries from Lake
Michigan, still considerably less volatile compared to recent days.
Lake influence lingers with stratocu streamers reaching into the
terminal corridor but with low predictability on location and
duration. A general VFR scattered forecast is preferred during this
time and adjusted with later observations. More of a diurnal cloud
component then develops by Tuesday afternoon when broken coverage of
VFR below 5000ft becomes favored. The best chance for a benign
pattern of flurries occurs late in the day when combined with
additional lake effect contributions into Tuesday evening.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling 5000 feet or less this evening and Tuesday
  afternoon.

&&

.PREV DISCUSSION...
Issued at 331 PM EST Mon Jan 30 2023

DISCUSSION...

12z DTX indicated low level saturation with an -11 C temp at both
the 850 & 700 MB levels. Continued cooling into DGZ and some 700 MB
FGEN/lift lead to some good flake-size this morning, but the 70 knot
jet core at 700 MB has since passed and moved into Eastern Great
Lakes. Good subsidence and drying taking place through this evening,
as 850 MB dew pt depressions increase to 30-40 C. Still will need
scour out some residual low clouds around the 925 MB level, but with
light northwest winds, expecting at least partial clearing for much
of the CWA. As such, looking at low temperatures in the +5 to -5 F
range tonight across southeast Michigan, in line with Euro Mos
guidance. Coldest temperatures will reside across the north half of
the CWA with the deep snow pack. Farther south, there looks to be
some mid clouds along the southern Michigan border with sheared out
upper level PV lifting through the Ohio valley. These higher clouds,
coupled with urban heat island of Detroit/Wayne county should keep
temps elevated in single numbers. Pronounced surface ridging and
extreme dry air at the 850 MB should prevent snow showers activity
despite that mid level forcing. Although, when it gets this cold, a
shallow low level cloud layer could produce flurries. Flurry chances
certainly will increase during the day on Tuesday as low level winds
back to the west and then west-southwest by Tuesday evening. Hi-res
models do not generate any measurable QPF, but a couple tenths of
snow seems possible with favorable 925-850 MB thermal profiles, and
will carry flurries/isolated light snow showers for late Tuesday/Tuesday
evening in line with local SREF weighted probabilistic guidance. NAM
soundings also showing substantial layer of supersaturation with
respect to ice with the DGZ, especially across middle/northern tier
of the CWA, giving confidence in flurries/very light snow showers.

Sprawling surface high pressure over the Ohio Valley on Wednesday
gives way to arctic front to move through the Central Great Lakes
Thursday afternoon/evening. Return flow around the high allows
temperature to rise into the 20s for Wednesday, with further warming
ahead of the front on Thursday, but potentially coming up just short
of the freezing mark.

The European lead medium range models remain consistent with the
heart of the arctic air moving through New England on Friday, but
southeast Michigan looks to be on the western Fringe of a tight
temperature gradient, with 850 MB temps lowering to at least -20 C
Friday morning over the bulk of southeast Michigan, with -25 C over
Lake Huron. Despite the glancing blow, enough wind expected for
wind chills to bottom out around -15 F Friday-Saturday morning
with mins aob zero and daytime highs stuck in the teens on Friday.

MARINE...

West to west northwest winds have set up across the central Great
Lakes today as we reside as the Great Lakes resides on the east end
of a high pressure system across the central plains. Arctic air is
also moving into the region this afternoon and leading to mixing
heights over the lake above 5,000 feet. Low level flow within this
mixing layer is below 30 knots, so gust potential will top out
around 25 knots through the rest of today. The combination of arctic
air and the elevated winds brings moderate freezing spray conditions
to central and northern Great Lakes tonight. Winds decrease
gradually towards sunrise as the surface high pressure drifts
southeastward through Illinois and eventually into the Ohio Valley
by Wednesday. This will result in a period of lower winds Tuesday
morning and afternoon before winds increase out of the WSW Tuesday
evening as a shortwave moves through the broad upper troughing
across the region. Wind remain elevated through mid-week as the
arctic airmass lingers over the region. There is potential for a
period of gales Thursday afternoon and evening as a reinforcing
blast of arctic air arrives which brings widespread moderate to
freezing spray across Lake Huron.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.

&&

$$

AVIATION.....BT
DISCUSSION...SF
MARINE.......AA


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