Expert Forecast Opinion

346
FXUS63 KDTX 241837
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
237 PM EDT Tue Mar 24 2026

.KEY MESSAGES...

- Mainly dry and turning much warmer Wednesday and Thursday.

- Showers are likely Thursday, with a few embedded thunderstorms
possible, but severe weather potential is low.

- Colder air fills in Thursday night and Friday, then a warming trend
ensues over the weekend and into next week.

&&

.DISCUSSION...

A thicker canopy of clouds persists this evening and into the
overnight hours, associated with an axis of troughing that extends
from the Great Lakes into far northern Quebec. Forward progress of
this feature slows due to the persistence of a lower tropospheric
anticyclone. It will eventually dislodge from the upper Ohio Valley,
and then drift toward the Mid-Atlantic overnight. After veering
westerly, weakening flow flips southeasterly late tonight after the
departure of surface high pressure influence. Still chilly tonight
as temperatures drop to around the freezing mark.

A confluent warm advection regime moves in from the southwest on
Wednesday as geopotential heights start to rise. Longer wavelength
ridging aloft begins dislodging from western CONUS, reinforcing a
period of warming temperatures locally through Thursday. An elevated
warm front lifts in Wednesday marked by 925 mb temperatures rising
above 0C across the forecast area. In spite of shallow mixing depths
and more cloud cover than sun, readings should still peak above
normal (mid to upper 50s). Differential temperature advection
continues Wednesday night as 925 mb temperatures cross into the
double digits (Celsius) and the nocturnal temperature curve remains
nearly-flat. A mainly dry forecast is advertised Wednesday and
Wednesday night, but since the CAM window now extends through 12Z,
some disagreements exist.

No prevailing precipitation concerns Wednesday or Wednesday night,
but a period of upper level divergence with a saturated mid-upper
column lends marginal PoPs midday. However, forecast soundings are
very dry (and stable) below 700 mb (9.5 kft AGL), thus favoring just
a bit of virga or sprinkles. A speed max embedded within the apex of
the flattening ridge strengthens over the northern Great Lakes late
Wednesday night triggering convection, while nocturnal instability
over northern Indiana/Ohio leads to the same. As of now, Southeast
Michigan appears buffered from these features, therefore a dry
forecast will be maintained through 12Z Thursday.

An elongated corridor of troughing/baroclinicity gets forced in from
the west on Thursday, complete with low-level ThetaE advection ahead
of it. The preceding warm sector will be quite warm, although
unlikely to break any records (81F in 2007 at DTW). A cold frontal
passage is expected to eventually produce scattered to widespread
showers, including some thunderstorms, as it moves through Thursday.
Questions remain as to the productivity of the pre-frontal warm
sector as medium-range solutions are split on QPF through the midday
southwest-flow regime. Greatest QPF potential exists along the
frontal zone with a strong FGEN response, but limitations exist in
the favorability of the ambient environment. Mid-level lapse rates
are poor, and surface-based instability is far from guaranteed (see
24.12Z NAM and operational GFS). But given a jump in effective shear
(+40 knots) and opportunities for periods of elevated instability
(MUCAPE), a few embedded storms are probable. Severe threat will
remain low, unless SBCAPE trends much higher. This would
predominantly present a wind threat.

The front should clear through by late evening Thursday, concluding
precipitation, and leading to a quick post-frontal cooldown. Flash-
freeze concerns exist north of the M-46 corridor where temperatures
drop further and earlier, but stronger gradient winds should help to
evaporate residual surface water Thursday night further south. Highs
will be about 30F colder Friday compared to Thursday, then a gradual
warm-up begins through the weekend and into next week. A series of
northern shortwaves offer a few chances for light rain showers
Sunday and Monday.

&&

.MARINE...

A weak cold front tied to northern Ontario low pressure glances the
northern portions of Lake Huron late this afternoon-evening offering
a few snow showers. Front vacates latter half of the evening
allowing winds across the central Great Lakes to weaken and turn
light overnight. Midweek period is characterized by low pressure
passing just to our north over Lake Superior/northern Ontario. Aside
for a chance at rain-snow showers over northern Lake Huron,
southerly winds remain modest around or below 20kts. This system
eventually drags a fairly strong cold front through the Great Lakes
latter half of the day Thursday bringing scattered to numerous rain
showers as well as thunderstorm chances Thursday evening over the
southern Great Lakes. A few of these storms could be strong to
severe with wind and hail being the main hazards. Northerly winds
quickly strengthen behind the front late Thursday evening/night with
a few hour period where gusts could approach gales (currently ~25%
chance to reach 34kts).

&&

.HYDROLOGY...

Showers are likely Thursday as a cold front quickly moves through
Lower Michigan. A few embedded thunderstorms are possible, more so
for areas along/south of I-94. Consensus modeled rainfall totals
remain between a quarter and a half inch through Thursday evening.
Flood potential is rather low, but ponding amidst low-lying and poor
drainage areas may develop, especially if any heavier thunderstorm
activity occurs. Localized exceedance of a half inch of rainfall
could occur. Mainly dry conditions are expected from now until
Thursday, and then again over the weekend.

&&

.PREV DISCUSSION...
Issued at 143 PM EDT Tue Mar 24 2026

AVIATION...

A brief period of MVFR BKN clouds developed earlier this afternoon
across the southern metro terminals, but dry air has won out and VFR
skies are expected to prevail. A mix of BKN/OVC mid and high clouds
are expected throughout today into tomorrow. Southwest flow to
around 15 knots this afternoon will decrease this evening and back
towards the south to southeast. The southeast winds tonight bring
low potential for patchy fog across the southern metro terminals
before daybreak tomorrow. Confidence too low to mention at this
time.

DTW THRESHOLD PROBABILITIES...

* None.


&&

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

$$

DISCUSSION...KGK
MARINE.......KDK
HYDROLOGY....KGK
AVIATION.....AA


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