607
FXUS63 KDTX 160753
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
353 AM EDT Mon Sep 16 2024

.KEY MESSAGES...

- Seasonably warm and dry conditions prevail through the week.

- High temperatures remain above normal but settle into the upper 70s
  with a cloud increase during mid week.

- Readings return to the lower 80s Friday into next weekend.

&&

.DISCUSSION...

We begin the week with more of the same outstanding mid September
weather across SE Mi as surface high pressure combines with a
blocking ridge aloft to produce clear sky over the region today.
Full sun is also still made hazy by some lingering high altitude
forest fire smoke that has been slow to dissipate within the weak
wind profile. High temperatures in the lower to mid 80s return this
afternoon with readings at the cooler end of the range toward the
Huron and Erie shorelines.

After a repeat performance Tuesday, the forecast highlight is on the
Mid Atlantic tropical system and its evolution during the mid to
late week period. Model trends still cast some uncertainty on
favored solutions due to a fair amount of spread still shown on the
westward extent of the 500 mb circulation and moisture field. The
00Z GFS run made a noticeable shift to a slower/farther south
solution more in line with the ECMWF vs the farther north NAM and
Canadian runs. All of the regional and global deterministic models
are in much better agreement on energetic split 500 mb flow over the
west half of North America and show solid predictability through
little to no variation over the last several model runs. The favored
larger scale downstream influence from the Rockies long wave trough
reinforces the ridge portion of the rex block across Ontario and the
Great Lakes. This in turn holds low pressure farther south and
eventually east, and trends the SE Mi forecast away from measurable
rain during the Wednesday time period.

Late week evolution of the large scale pattern also results
temperatures a few degrees cooler but still above normal into next
weekend. The overall strength of the rex ridge settles from about
588 dm height to about 582 dm by Wednesday into Thursday. The
associated thickness cooling then trims a few degrees off high
temperatures compared to recent days. Guidance hovering in the upper
70s to lower 80s looks reasonable through the period.

&&

.MARINE...

High pressure continues to dominate conditions across the central
Great Lakes through the first half of the week. Light (aob 15kts)
southerly flow holds through today before turning back to more
easterly for the midweek period.

&&

.PREV DISCUSSION...
Issued at 1157 PM EDT Sun Sep 15 2024

AVIATION...

Expansive area of high pressure maintains influence this period.
This ensures dry and stable conditions, precluding lower cloud
development. Shallow ground fog will again be possible at daybreak
Monday due to favorable radiative cooling conditions. Light winds
generally from the southeast persist.

For DTW/D21 Convection... Thunderstorms are not in the forecast for
the foreseeable future.

 DTW THRESHOLD PROBABILITIES...

* None.


&&

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

$$

DISCUSSION...BT
MARINE.......KDK
AVIATION.....MR


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