Orion, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

395
FXUS63 KDTX 071025
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
625 AM EDT Thu Aug 7 2025

.KEY MESSAGES...

- Isolated to scattered thunderstorms today and again Friday. Severe
weather is not anticipated but localized heavy rainfall will be
possible.

- Hot and muggy weather builds in this weekend with heat index well
into the 90s Saturday through Monday.

&&

.AVIATION...

Building heights and increased midlevel subsidence will lead to
warming aloft across Southeast Michigan today. There has been some
signal for isolated/scattered shower activity this afternoon mainly
in the interior Thumb for those areas that have pooled surface based
moisture along increased convergence axis/lake breeze boundary.
Otherwise, confidence is increasing in dry conditions at the Detroit
terminals. VFR conditions outside of any shower activity. South wind
trajectory today and tonight.

For DTW/D21 Convection... At this time, thunderstorm potential is
too low to include in the forecast.

THRESHOLD PROBABILITIES...

* Low for thunderstorms Thursday afternoon.

&&

.PREV DISCUSSION...
Issued at 346 AM EDT Thu Aug 7 2025

DISCUSSION...

Overnight clearing and near saturated conditions in the nocturnal
boundary layer are supporting another round of patchy early morning
fog across the area - this should clear shortly after sunrise.
Meanwhile, a subtle shortwave within weak WNW flow aloft is passing
over the Lower Peninsula at press time. As this wave departs east by
early afternoon, weak subsidence and minimal PV advection will offer
a weakly capped environment devoid of organized forcing through much
of the afternoon. At the surface and mid levels, weak south to
southwest wind will result in increasing boundary layer temperature
and moisture as a theta-e ridge expands in from the Midwest. High
temp in the mid to upper 80s will feel closer to 90 at times as dew
point sits in the mid 60s.

00z model guidance has trended toward a more robust theta-e ridge
resulting in higher instability this afternoon - MLCAPE generally up
to 1500 J/kg. Despite the lack in support for ascent aloft, similar
to yesterday there will be trigger mechanisms available via lake
breeze and surface convergence boundaries. This offers another
window for diurnally driven scattered showers and isolated
thunderstorms mainly between 2pm and 8pm. If storms do initiate, the
environment will support multicell mode given bulk wind shear
reaching 25 to 30 kt. Storm motion will remain relatively slow at
around 10 to 20 mph which will pose a threat for localized heavy
rainfall as PWAT holds steady in the 1.25 to 1.50" range. The
strongest cells will also be capable of wind gusts of up to around
40 mph but generally the relatively moist boundary layer should keep
DCAPE in check today. Highest chances for precip - around 25 to 30% -
are mainly focused across inland areas.

A similar environment will hold in place through Friday, but with
slightly higher likelihood for convection to develop as a remnant
MCV and attendant shortwave pass through, inducing a weaker cap and
stronger forcing for ascent. Hi-res guidance favors a weakening
trend to the MCS as it tracks from S WI/N IL across Lake Michigan
overnight tonight, but there remains the potential for some
semblance of the convection to reach the area late Friday morning.
Regardless of morning convection, the remnant MCV tracking into the
resident moist and unstable environment during the afternoon will be
capable of triggering additional convection overhead. Similar
instability and wind shear parameters compared to today, but with
slightly higher PWATs, point to locally heavy rainfall again being
the primary threat with any convection.

An upper low tracking into the northern Plains will force a ridge to
crest overhead on Saturday and pass just to the east on Sunday,
allowing the core of the Midwest theta-e ridge to take residence
this weekend. Hot and muggy weather is in store with 850mb temp in
the upper teens to near 20 C supportive of highs in the lower 90s.
Steady southerly flow advects in dew points around 70 to hold
daytime heat index in the mid to upper 90s. The background rising
height field should maintain a mostly stable profile and low
probability for convection on Saturday, but by late Sunday chances
for precip increase across the north and west as the ridge begins to
break down. The surface cold front tied to the northern Plains low
will stall just upstream, keeping the heat around into Monday. This
front eventually looks to pass through in the Tuesday to Wednesday
time frame as a lobe of the upper low pivots across the Great Lakes.
This will bring the next chances for thunderstorms as well as
slightly lower temps midweek.

MARINE...

South-southeast flow in place today following the departure of high
pressure. Peak winds expected over the northern half of Lake Huron,
given the fetch, with gusts up around 15-20kts. The rest of the
region sees slightly weaker wind gusts closer to 10-15kts.
Shower/storm chances during the day today are generally confined
towards the nearshore waters with the bulk of activity occuring
overland. Better chances to see scattered thunderstorms over the
open waters of Lake Huron comes late this evening into Friday as a
weak warm front lifts into the upper Great Lakes. Region remains on
the northern edge of a central CONUS ridge Friday through the
weekend which brings continued lighter southerly winds and periodic
scattered storm chances.

&&

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

$$

AVIATION.....CB
DISCUSSION...TF
MARINE.......KDK


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at www.weather.gov/detroit.