356
fxus63 kdtx 050351
afddtx
area forecast discussion
national weather service detroit/pontiac mi
1051 pm est tue feb 4 2025
.key messages...
- seasonably chilly but otherwise pleasant weather tonight through
wednesday.
- a chance of light snow by late afternoon leads into the
highlighted mixed precipitation event that begins late wednesday
evening and continues into thursday morning.
- a brief period of snow occurs ahead of a rapid transition to
longer-duration freezing rain for metro detroit while the transition
is slower north of i-69 with greater snow/sleet totals.
- colder air returns thursday night with gusty westerly winds, in
excess of 30 mph at times.
- another mixed precipitation event is possible this weekend with
potential for accumulating snowfall and additional icing.
&&
.aviation...
high pressure and dry low level air will maintain light winds and
clear skies below 5000 feet through wednesday morning. mid and high
level clouds will however remain prevalent. an upper level frontal
boundary will support a chance of light snow late wed afternoon.
given the dry low levels, ceilings are likely to remain vfr with any
light snow.
for dtw...an influx of moisture and elevated warm air will support
an 70 percent chance of freezing rain and sleet in the 07z to 12z
thursday time frame.
dtw threshold probabilities...
* moderate in freezing rain overnight wednesday into early thursday
morning.
&&
.prev discussion...
issued at 413 pm est tue feb 4 2025
discussion...
cold nw flow leading surface high pressure into the great lakes has
activated lake effect with just enough convective depth for a stray
snow shower in central lower mi and the thumb this afternoon.
daytime instability in a generously supersaturated boundary layer is
responsible for times of flurries and also a few breaks of sunshine
across the rest of se mi. these conditions fade into a seasonably
chilly but otherwise pleasant stretch of weather tonight through
wednesday morning as high pressure settles across lower mi.
temperatures wednesday struggle rising back into the 20s setting the
stage in advance of the mixed precipitation event featured over the
last several forecast cycles. consensus of model guidance maintains
the larger scale conditions favorable for a quick transition through
precipitation types wednesday evening over the bulk of central and
southern lower mi. forecast instability is centered more on qpf
beginning as soon as wednesday afternoon in the leading band of fgen
enhanced isentropic lift shown especially in hi-res models vs less
so in coarser deterministic solutions. entry level pops are
maintained toward the ohio border for some light snow that could
make it through an otherwise formidable dry layer below cloud base.
that leads into the main event later wednesday evening into thursday
morning in which qpf is trending lower for se mi. this is primarily
due to the rapid west to east progression of the already narrow and
broken precipitation axis. assuming deeper convection occurs well
south into the ohio valley, closer to the surface warm front, then
lower precipitation totals are plausible in shallower convection or
isentropically transported moisture through the mid level of the
frontal zone. the parent mid level wave and upper level jet then
drive a surge of dry air into the region that quickly brings an end
to the event in se mi. otherwise there are no changes to overall
expectations of a quick snow to freezing rain transition toward
metro detroit up toward flint and a slower transition and/or more of
a snow/sleet component farther north toward the tri cities and
northern thumb. the event remains worthy of shorter fused advisory
coverage in later updates to allow for time to confirm trends on
lower ice/snow amounts and shorter duration.
the quicker exit timing of wednesday night precipitation is
partially due to the deepening of canadian low pressure centered in
northern ontario by thursday morning. the ohio valley wave occludes
while grazing se mi which allows a temperature rebound above
freezing for a few hours followed by a surge of cold air thursday
night driven in by gusty west wind tied to the ontario system. lake
effect is activated but is once again muted by lower convective
depth and shorter fetch into se mi through friday. more significant
is the reset that polar high pressure brings for a potential repeat
performance of mixed precipitation this weekend. early indications
in extended range models suggest a larger low pressure system on a
similar tn/oh valley track capable of higher precipitation totals
for a longer duration beginning early saturday through saturday
night.
marine...
northwest wind gradually diminishes this evening into tonight as
cold air advection tapers off and high pressure builds directly into
the great lakes. small craft advisories remain in effect for the
lake huron nearshore waters where elevated wave action will persist
through the evening. light winds and waves follow for wednesday. a
low pressure system then tracks through the great lakes late
wednesday night through thursday morning, bringing light snow and a
wintry mix to the area. strong westerly winds follow this system
thursday night within the next surge of arctic air. probabilities
continue to favor gusts to gale force, especially across northern
lake huron where latest forecast data offers a 30% to 40% chance of
strong gales of up to 45 knots. a gale watch has been issued for the
whole lake from thursday afternoon to friday morning. snow
showers/squalls and freezing spray will likely accompany the arctic
air thursday night into friday.
&&
.dtx watches/warnings/advisories...
mi...none.
lake huron...gale watch from thursday afternoon through friday morning for
lhz361>363-421-422-441>443-462>464.
lake st clair...none.
michigan waters of lake erie...none.
&&
$$
aviation.....sc
discussion...bt
marine.......tf
you can obtain your latest national weather service forecasts online
at www.weather.gov/detroit.