Pontiac, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

490
FXUS63 KDTX 261828
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
228 PM EDT Thu Mar 26 2026

.KEY MESSAGES...

- Showers and thunderstorms develop this afternoon and taper off in
the evening hours. There is a Slight Risk of severe storms along and
south of the I-94 corridor, with all hazards (wind, hail, and
tornadoes) possible.

- Sharply colder air arrives tonight and Friday, followed by a
steady warming trend through the weekend and into early next week.

&&

.AVIATION...

A cold front currently dropping south through the region is draped
from Lansing to Pontiac to Mount Clemens. The front is expected to
drop south into Ohio by roughly 21-22Z. Expecting the bulk of
surface based storms to occur south of the region but elevated
portions of the front will light up over the next few hours through
this evening providing chances of showers and thunderstorms. After
the precipitation, cold air advection will surge which looks to
result in a period of IFR stratus before the drier air can scour it
out late tonight into Friday morning. Winds flip around to the north
in the wake of the front and hold through the end of the forecast.

DTW Convection....Scattered thunderstorms are forecast across the
airspace after 20Z for a few hours. After the first couple hours of
more isolated storms, there could be a more organized line of storms
south of DTW which could impact the Toledo region between 21Z and
00Z.

DTW THRESHOLD PROBABILITIES...

* High for cigs below 5000 ft this afternoon and tonight.

* Moderate in thunderstorms this afternoon and evening.

&&

.PREV DISCUSSION...
Issued at 245 AM EDT Thu Mar 26 2026

DISCUSSION...

Yesterday`s late-day warm advection surge allowed temperatures to
reach into the 60-65 degree range late in the day for areas along and
west of U.S. 23, as the 00Z DTX sounding revealed a 925-mb
temperature of 11C. Although it remains mild this morning
(40s/50s), the air mass remains dry and stable, as surface dew points
are mostly in the 30s. The primary focus of this forecast cycle
remains the potential for severe weather today and the subsequent
cold shot behind the frontal boundary tonight/Friday.

Model Analysis (00Z NAM/HRRR/Regional GEM): The 00Z suite shows high
confidence in the timing of the pre-frontal warm sector expansion.
925 mb temperatures are progged to continue to increase to +12C to
+14C by 18Z over southern areas. The 00Z NAM continues to be the
most aggressive with the northward extent of surface-based
instability, bringing a narrow tongue of 800-1200 J/kg SBCAPE into
the I-94 corridor by 21Z. Caveat: The 00Z NAM is very sensitive to
dew point recovery. If 60F dew points fail to clear the Ohio
border, the severe threat will remain largely elevated, favoring hail
over wind, as elevated MUCAPEs look to exceed 1000 J/kg as well. At
the present time, one needs to look upstream all the way back to
Missouri to find any dew points close to 60F.

The HRRR (00Z) is slightly more tempered with instability due to
concerns over residual cloud debris from morning isentropic lift but
compensates with more robust convective organization along the
actual cold front; however, this occurs mostly south of the state
border. The Regional GEM (00Z) provides a middle-ground solution,
highlighting a potent 850-mb jet of 45-50 knots. This creates a high-
shear/low-CAPE (HSLC) environment where 0-6km bulk shear values
exceed 50 knots. Straight-line hodographs suggest a primary damaging
wind threat, though low-level curvature in close proximity to the
surface low center tracking along or near the Michigan border could
support isolated tornadoes if cells can remain discrete before
transitioning to a linear mode.

SPC Day 1 continues to highlight areas along and south of I-94 in
the Slight Risk. Hazards: Damaging winds (65+ mph), large hail
(2"+), and an isolated strong tornado threat remains, with the most
likely severe window between 3:00 PM and 8:00 PM. Severe chances
quickly taper off north of I-94, but there could be a marginal
severe threat as far north of M-59, but most likely just hail with
steep mid level lapse rates.

A significant surface temperature drop is expected in the evening
hours from north to south, with brisk northerly winds kicking in.
Fortunately, forecast soundings show a deep dry slot immediately
following the front, which should curtail post-frontal precipitation
before a changeover to snow occurs.

On Friday, expect a blustery, raw day. Highs will struggle to reach
40F. Low-level lapse rates will be steep under the cold core, which
could result in "rogue" cellular flurries or graupel showers,
especially in the Thumb region with fetch off Lake Huron. However, it
appears inversion heights will be too low and the mid-level dry slot
will be too much to overcome; consequently, the forecast will remain
dry for now.

The ECMWF ensemble remains in good agreement regarding the magnitude
of the cold air mass, but the heart of the cold air does not arrive
until Friday night when 850-mb temps bottom out around -13C or so,
which is roughly two standard deviations below the climatological
mean for late March. NBM temperatures appear to be too warm for
Friday night, and would expect most locations to dip into the teens.

Surface high pressure slides to the south on Saturday, allowing for
a quick return to southwesterly flow. However, the ECMWF ensemble
members still only indicating highs in the lower 40s coming off the
cold start.

The longwave pattern shifts toward a more zonal to even slightly
ridged configuration by early next week. Global ensemble (GEFS/EPS)
clusters and Canadian GDPS suggest a significant warm-up by Tuesday,
with another potential deep trough developing over the Western US.
This setup often signals a return to active, springlike weather for
the Great Lakes by the middle of next week.

MARINE...

High pressure influence wanes today as a fast moving upper level
wave provides a much stronger wind field aloft, and eventually drags
a low pressure system through the Great Lakes. The system will also
force a strong cold front through the region with thunderstorms
developing along the frontal slope. Locally higher winds/waves are
possible in some storms, and a few could intensify to meet
thresholds for Marine Weather Statements and/or Special Marine
Warnings. All convective hazards are possible in isolated fashion
(i.e. +34 knot gusts, +0.75 inch hail, waterspouts), particularly
during the evening hours for the southern waterways (Lake St. Clair
and western Erie). Post-frontal cooling will be stark, but a
decrease in low-level northerly flow should limit nocturnal mixed-
layer gustiness to below 30 knots. Modest on-shore post-frontal
gradient winds suggest high confidence in Small Craft Advisory level
waves, which remains in effect.

HYDROLOGY...

Showers and scattered thunderstorms are expected to develop Thursday
afternoon ahead of a cold front sweeping through Lower Michigan.
Consensus model guidance QPF totals generally between 0.25 and 0.75
inches through Thursday evening, with the higher totals near the
southern Michigan border.

While the broader river flood potential remains low due to
relatively high infiltration capacity from a recent dry spell and
current river levels sitting at or below normal for late March,
localized issues cannot be ruled out. The primary concern is for
urban areas and small streams south of the M-59 corridor, where high-
intensity rainfall rates within embedded thunderstorms could lead to
localized ponding or rapid rises. Flash flood guidance (FFG) remains
high (6-hour FFG mainly above 2.0 inches), and current rainfall
projections are well below these thresholds. No significant
hydrologic impacts are expected at the main stem river forecast
points at this time.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from 10 PM this evening to 4 PM EDT Friday for
     LHZ421-441>443.

     Small Craft Advisory from 10 PM this evening to 10 AM EDT Friday
     for LHZ422.

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

$$

AVIATION.....DRK
DISCUSSION...SF
MARINE.......KGK
HYDROLOGY....SF


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