462
FXUS63 KDTX 091902
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
302 PM EDT Sun Jun 9 2024

.KEY MESSAGES...

- Late day showers will mainly develop over The Thumb region with
  lighter rates further south and east. A rumble of thunder also
  possible.

- Gusts peak near 30 mph late today before subsiding overnight.

- High pressure brings dry conditions for the first half of the
  week.

- Cool on Monday followed by a warming trend back into the mid to
  upper 80s by latter half of the week.

&&

.DISCUSSION...

Southeast Michigan positioned late this afternoon within the broad
cyclonic expanse of a closed low lifting into southern Quebec. Weak
cold frontal passage underway marking the transition toward deeper
layer northerly flow. Interludes of dcva within a perturbed mid
level environment in combination with cold/moist air advection will
offer a greater coverage of cloud cover going forward through
tonight. Overall moisture quality is limited, but proving sufficient
with a diurnal boost to provide some widely scattered showers. Depth
to this convective activity marginal for thunder, but worthy of a
mention noting an earlier strike over lake Huron. Greater
probability will exist across the thumb going forward into the
evening hours. The northwest gradient and cloud cover will help keep
temps elevated slightly overnight. Readings bottom out in the upper
40s most locales.

Cooler northerly flow entrenched throughout Monday as high amplitude
troughing takes residence just to the east. Lingering early day
cloud vacates as shallow moisture effectively mixes out with daytime
heating. Despite the increasing insolation potential with time,
existing thermal profile will ensure highs arrive a solid 10 degrees
below average. The onshore trajectory will make eclipsing 60 degrees
a struggle for areas right along the lake huron shoreline.
Seasonable mid June environment returns Tuesday as the upper height
field recovers modestly atop surface high pressure. Full insolation
potential into an increasing mean thickness field supports a
standard warming trend with temps back to average.

Initial period of warm air advection emerges Tuesday night into
Wednesday as a low amplitude wave glances across the northern great
lakes. Moisture quality lacks to support highlighting anything
outside of some increase in mid level cloud at this stage, while
bringing an uptick in projected lows and highs as dewpoints inch
upward. A meaningful increase in humidity occurs within the
background of a well above average thermal field Thursday under
strengthening southwest flow. Improving convective potential during
the late week period given the underlying thermodynamics and
energetic lower amplitude upper level westerly flow positioned north
of prevalent southern conus ridging.

&&

.MARINE...

Pockets of afternoon showers vacate over the course of this evening
as low pressure over Quebec finally dislodges eastward. While this
will allow winds to weaken some, lingering gradient likely supports
northerly gusts around 20kts through much of Monday (25kts possible
through Monday morning over central Lake Huron) despite high
pressure beginning to build overhead. Small craft advisories remain
in effect around the Thumb as the wind shift brings higher wave
action into the nearshore waters. Aforementioned high becomes fully
established over the Great Lakes Monday night leading to a period of
dry conditions and light wind through the midweek period.

&&

.PREV DISCUSSION...
Issued at 200 PM EDT Sun Jun 9 2024

AVIATION...

Diurnal cloud response underway as a deep mixed-layer develops this
afternoon. Not only does this support the expansion of high-based
VFR cumulus, but 30+ knot flow within the low-levels will continue
to mix down producing similar peak wind gusts. Winds generally hold
from 260-280 degrees until a weak frontal boundary crosses from
northwest to southeast over the next 3-4 hours. Some showers have
accompanied the FROPA, but most of this activity should remain over
The Thumb and points east of the terminals. Winds behind the front
veer toward 310 degrees while maintaining some gustiness until this
evening, but speeds should decline enough to hold below crosswind
thresholds (for DTW). Clouds linger tonight as low-level cold
advection helps to cool and moisten the column leading to lowering
of cloud bases with time. A period of high-end MVFR ceilings remains
possible after midnight. Low clouds mix out late Monday morning with
weak energy aloft touching off a period of VFR mid and high clouds
during the midday timeframe.

For DTW/D21 Convection...Thunderstorms are not expected through the
TAF period.

 DTW THRESHOLD PROBABILITIES...

* Low in ceilings at or below 5000 feet this afternoon.

* Low in exceeding crosswind threshold.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ422.

     Small Craft Advisory until 4 PM EDT Monday for LHZ421.

     Small Craft Advisory from 2 AM to 10 PM EDT Monday for LHZ441>443.

Lake St Clair...Small Craft Advisory until 10 PM EDT this evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EDT this evening for LEZ444.

&&

$$

DISCUSSION...MR
MARINE.......KDK
AVIATION.....KGK


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