579
FXUS63 KDTX 261142
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
742 AM EDT Wed Mar 26 2025

.KEY MESSAGES...

* Chilly start to the morning with wind chills near 20F.
  Temperatures warm into the mid-40s by this afternoon.

* Gradual warm up expected Thursday through this weekend.
  Temperatures in the 50s on Thursday and 60s by Friday-Saturday.

* A warm front lifts into the region on Friday, kicking off shower
  and thunderstorm chances that persist through the weekend. Heavy
  rainfall is possible this weekend.

&&

.AVIATION...

Moisture trapped below and within a midlevel inversion has resulted
in a persistence of MVFR to VFR stratus this morning across
Southeast Michigan. Continued dry northwest flow with daytime mixing
will help to scatter out the clouds in the first few hours of the
taf period. Subsidence under confluence aloft will support VFR
conditions throughout the remainder of the period.

.DTW THRESHOLD PROBABILITIES...

* Low for ceilings at or below 5000 feet beyond this morning.

&&

.PREV DISCUSSION...
Issued at 425 AM EDT Wed Mar 26 2025

DISCUSSION...

Upper low vacates into New England today, prompting a period of
height rises over SE Michigan through Thursday. The thermal trough
follows suit to warm 850mb temperatures gradually toward 0 C by
Thursday evening. Overall dry and sunny conditions are anticipated
today with highs in the mid-40s. Glancing mid-level impulse slides
over western lower Michigan tonight which will result in a brief
period of cloud cover overnight and possibly some virga on radar.
That said, dry low levels should be sufficient to prevent any liquid
from reaching the ground.

High pressure continues to govern conditions daytime Thursday with
another quiet day expected. A PV anomaly dives toward the Great
Lakes Thursday evening but ultimately shears off to the east with
little fanfare. Main impact from this will be a weakening cold front
that stalls/washes out over central Lower Michigan late Thursday
night.

The strongest warm advection occurs on Friday as mid-Atlantic high
pressure gains influence and lifts a warm front into the area. 850mb
temperatures on Friday comfortably climb above 10 C, but forecast
high temperatures still exhibit large spread due to differences in
warm front timing. Near the Ohio border, there are a handful of
ensemble members forecasting highs in the 70s although the
interquartile range across the cwa is generally between 55-65
degrees. The warm front will also be responsible for an initial
round of precipitation chances to kick off an unsettled weekend
forecast. Moisture transport into the isentropic slope occurs well
upstream over the Plains, generating showers and thunderstorms that
lift into the Ohio Valley early Friday morning and into SE Michigan
later in the day on the nose of the 850mb jet. While we are still a
couple forecast cycles away from CAM output, varying degrees of
MUCAPE are present in the global/regional models which wanes as the
front tracks through. So not out of the question to see elevated
convection on Friday.

By Saturday morning, the warm front settles over northern lower
Michigan with the resulting baroclinic zone becoming the track for
low pressure to ripple along on Saturday. All models show some
meridional fluctuations to the front during this period, with a
sharp thermal gradient featuring temperatures in the 30s north of
the front versus mid 60s-low 70s south. Deterministic and ensemble
guidance alike show substantial spread in the positioning of this
front throughout the day Saturday, with some guidance (i.e. 00z GFS)
bringing the front as far south as the M-59 corridor. Not only will
this impact the temperature forecast, but also the precipitation
forecast. Two features will be at play on Saturday: frontal
convergence as already noted, and a southern stream shortwave that
will merge with the mean flow later in the day. Both features
generate seasonably high moisture content, with PWAT values of
greater than 1 inch which will prime the environment for heavy
rainfall. The details are in the dynamics here, with many plausible
outcomes still in play for Saturday and Saturday night depending on
factors like frontal positioning, track of the southern stream wave,
strength of said wave, etc. Confidence is low in QPF amounts, and as
noted in the previous forecast cannot discount the tails of this
event forecasting rainfall amounts of 2+ inches when all is said and
done.

Unsettled weather continues into Sunday as the baroclinic zone
remains in tact and with a final wave of low pressure
developing/sweeping across the Great Lakes and Ohio Valley. An
opportunity for surface-based convection will exist on Sunday with
potential for more favorable kinematic fields that deserve
monitoring for severe weather potential. That said, there are many
failure points to get through this weekend so expect changes to the
forecast Sunday onward. A higher confidence item is once this low
tracks through, a cool down will be observed across the state.

MARINE...

Gusty northwest wind in the wake of an early morning cold front will
subside through the day as a broad area of high pressure builds in
from the west. This provides lighter winds through tonight before
wind organizes out of the southwest on Thursday in advance of the
next cold front tracking into the northern Great Lakes. This looks
to peak in the 20 to 25 knot range, but there will be a 40% chance
for a brief period of 30 to 35 knot gusts across northern Lake Huron
on Thursday afternoon as the front moves in and shifts wind to the
west/northwest. At this time confidence on occurrence and duration
remains too low, so no Gale Watch will be issued. A warm front
stalls across the region Friday into Sunday bringing a period of
stronger easterly winds and widespread precipitation as several
areas of low pressure track along the front.

&&

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

$$

AVIATION.....CB
DISCUSSION...MV
MARINE.......TF


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