665
FXUS63 KDTX 151700
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
100 PM EDT Sun Sep 15 2024

.KEY MESSAGES...

- Seasonably warm and dry conditions prevail through mid-week with
patchy morning fog Sunday through Tuesday.

- Spotty light rain becomes possible Wednesday.

&&

.AVIATION...

Large-scale pattern remains locked-in again through the TAF period
based on sprawling surface high pressure centered near Cape Cod.
This provides generally clear skies and light southeasterly winds
AOB 10 knots through the daylight hours. Wildfire smoke continues to
stream in aloft with negligible impact on overall sky fraction.
Persistence forecast warrants continuation of MVFR fog restrictions
Monday morning from PTK south with lower potential for brief
visibility drops to IFR. Based on previous observational trends, IFR
development is more likely for YIP and/or DET.

For DTW/D21 Convection...Thunderstorms are not forecast this week.

 DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 353 AM EDT Sun Sep 15 2024

DISCUSSION...

An outstanding mid September weekend wraps up with another day of
dry weather, warm temperatures, and moderate humidity. Full sun
filtered through high altitude forest fire smoke is the only minor
flaw of note but does little to prevent another round of high
temperatures in the mid 80s across SE Mi.

These conditions are a continuation of remarkably good weather in
the Great Lakes provided by a highly amplified and stable large
scale pattern across North America. The mid level ridge portion of a
mature rex block generally holds from the Great Lakes into the New
England states today through Tuesday while the low pressure portion
consists of inland Francine remnants combined with a mid Atlantic
hybrid tropical circulation. This mid Atlantic system is the
predictability challenge in the forecast for the next several days
and represents potentially our next chance of rain by mid week. The
westward trend in the mid level system track continues with some
notable timing spread among the new 00Z regional and global
deterministic models. NAM/GFS timing is considerably faster/farther
west compared to the ECMWF and Canadian possibly due to upstream
height falls across the central Rockies drawing the system westward
more quickly. The GFS is considerably faster than its ensemble mean
and an incremental POP increase might be best until some timing
clarification materializes in later model cycles. For now, dNBM/dt
reflects the general trend with a reasonable upward nudge to about a
20 POP in SE Mi late Tuesday night through Wednesday.

Extended global models indicate a tendency for northern stream short
wave energy lifting from the central Rockies into central Canada
during the late week. This is shown to build a new 500 mb mid level
ridge over northern Ontario to reinforce the eastern States rex
block. This could result in the closed low component of the block
lingering near the Great Lakes resulting in relatively unsettled
conditions Thursday and Friday.

MARINE...

High pressure continues to dominate conditions across the central
Great Lakes through at least the first half of next week. Southerly
flow develops today and persists into the first part of the work
week, though it will hold on the lighter side (aob 15kts).

&&

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

$$

AVIATION.....KGK
DISCUSSION...BT
MARINE.......KDK


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