Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000
FXUS63 KDTX 101856
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
256 PM EDT Mon May 10 2021

.DISCUSSION...

Seasonably cool May conditions again entrenched locally this
afternoon, owing to renewed height falls featured south of a closed
mid level circulation pivoting toward the northern great lakes.
Lower amplitude mid level impulse preceding this main height fall
center now transiting the lower peninsula, offering some mid level
cloud but absent of meaningful low level moisture advection. A brief
light shower or occasional sprinkle still plausible going forward
through the evening, as modest mid level ascent works to capitalize
on the underlying steeper lapse rate environment. Lingering evening
cloud will give way to a period of open sky overnight. Perpetuation
of a modest northwest gradient suggests some limitation to
radiational cooling, but the inbound main upper trough axis will
initiate another period of cold air advection throughout the morning
hours. Magnitude of the existing thermal profile will support lows
in the 30s all locations. Regionally collaborated frost/freeze
headlines highlight the general expectation for where a meaningful
dip below the freezing mark is more likely /northwest of metro
Detroit/.

Low-mid level thermal troughing maintains residence into the Tuesday
period - the reinforcing shot of colder air easing 850 mb
temperatures below -4C. Highs upper 40s to mid 50s. Standard diurnal
boundary layer destabilization will engage a cold, weakly cyclonic
mid level flow to provide a favorable background environment for
possible afternoon shower production. Lean moisture depth may tend
to limit the overall response in terms of coverage and duration,
supporting simply a lower probability mention. The cold
thermodynamic profile would encourage ice within the column should
healthier updrafts materialize, allowing for instances of small
hail/graupel and perhaps a rumble of thunder. High pressure nosing
into the region Tuesday night offers another frosty morning
Wednesday.

No significant weather through the late week period. Low level
anticyclonic flow remains a fixture during this time, as residual
mid level troughing or weak upper level low pressure struggles to
vacate the region. Lack of meaningful moisture quality or tangible
forcing through this window suggests dry conditions with an
incremental warming trend back toward seasonable levels by Thu-Fri.

&&

.MARINE...

High pressure begins to build over the region from the west tonight.
Moderate northwest winds continue through the day Tuesday as the
pressure gradient remains tightened over the central Great Lakes.
Strongest gusts will be across northern and central Lake Huron
reaching 25 knots. The offshore component should keep wave heights
in the Lake Huron nearshore waters at bay through midweek, although
choppy at times especially in portions of outer Saginaw Bay and
around the tip of the Thumb. Winds will trend lighter and more
variable towards Thursday as the core of the high pressure settles
overhead.

&&

.PREV DISCUSSION...
Issued at 200 PM EDT Mon May 10 2021

AVIATION...

A weak wave with associated VFR clouds will be moving across the
Great Lakes this afternoon. The majority of CIGS through the
afternoon will be 6-8 kft with only occasional FEW-SCT at or
slightly below 5 kft. Some light returns on the radar can be seen
this afternoon, but the dry low levels is preventing most of this
from reaching the ground. Will continue to leave any mention of
light rains showers out of the TAFs as it appears unlikely to impact
any terminals. VFR conditions continue into tonight with some
lingering FEW-SCT clouds and the potential for some clears skies for
at least part of the night.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling 5000 feet or less this afternoon and tonight.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Freeze Warning from 2 AM to 8 AM EDT Tuesday for MIZ047>049-053>055-
     060>063-068.

     Frost Advisory from 2 AM to 8 AM EDT Tuesday for MIZ069-070-075-076-
     082-083.

Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

DISCUSSION...MR
MARINE.......KDK
AVIATION.....AA


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