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afddtx

Area forecast discussion
National Weather Service Detroit/Pontiac Michigan
555 PM EST Fri Nov 22 2019



Aviation...

Ongoing mid level subsidence and its associated drying has been
leading to an erosion of the stratus deck late this afternoon, a
trend that is expected to continue this evening. This will remain
supportive of clearing this evening. The low level flow will back
toward the southwest over Lake Michigan tonight. There are
indications from several hi res model solutions which depict a low
stratus plume from Lake Michigan potentially impacting mbs around or
shortly after daybreak. Otherwise, no significant weather concerns
will impact the area into Saturday.

Dtw threshold probabilities...

* none

&&

Previous discussion...
issued at 303 PM EST Fri Nov 22 2019

Discussion...

A dry weekend looks to be on tap, with temps slightly below normal.

Broad upper level ridging building into the Great Lakes/Ontario this
evening, with low level warm advection/southwest winds/lowering
inversion height finally allowing most of the low clouds to
dissipate/mix out, except over northern lower Michigan extending
south into Tri-Cities region where the influence of Lake Michigan
will persist through the night as 925 mb temps remain sufficiently
cold enough. Going with mins in the 20s due to some uncertainty with
the low clouds. If there was higher confidence in clear skies
through the night, then upper teens look achievable in the normally
colder locations.

Compact upper wave entering southern Saskatchewan will be racing
east and the height fall center will be tracking through the
northern Great Lakes on Saturday. Meanwhile, closed/elongated upper
level low over the Central Plains opens up and tracks through the
southern Ohio Valley. 700 mb Theta-E ridge looks to rotate northward
and reach Southern Lake Erie into Northwest Ohio. It continues to
look like a real close call, but low level dry air is expected to
hold over Southeast Michigan as the next shortwave trough/energy
entering the western Great Lakes/Midwest Saturday evening should
assure the lead system remains progressive and pulls east. Even if
precip did somehow make it past the border, thermal profiles
suggests just rain becoming wet snow flakes.

A more robust shortwave/jet Max will streak through the northern
Great Lakes on Sunday, but the cold low level cyclonic flow looks to
struggle to get much farther south than northern lower Michigan. If
12z Euro is right, could be sneaky mild day with temps making a run
at 50 degrees based on temps of 3.5 c at the 925 mb level. Outgoing
forecast will feature mid 40s for now.

Upper level ridge off the Pacific northwest coast is forecasted to
buckle with upper level energy diving southeast from the Gulf of
Alaska tracking through The Four Corners region early next week and
advancing northeast through the Great Lakes region in the late
Tuesday-Wednesday time frame. Magnitude/timing discrepancies still
exist, with the Euro being one for the stronger/slower solutions,
while GFS is a faster/flatter one. Regardless, it appears Southeast
Michigan will reside on the mild/rain side of the system, with the
amount of wind/cold on the backside for Wednesday still up for
grabs.

Good ensemble model consensus with a strong upper level ridge
building into the Gulf of Mexico Thursday-Friday, with ridge axis
extending north through the Mississippi River valley/western Great
Lakes likely leading to tranquil weather over Southeast Michigan,
although will have to watch for position of the warm front to
possibly generate some light precipitation.

Marine...

Winds will continue to diminish this evening from a weakening
gradient as low pressure moves into eastern Ontario and a high
sliding into the Ohio Valley. A new low pressure system will track
up the Ohio Valley and into the northeast later Saturday. While the
center and tightest pressure gradients remain to the south and east,
there will likely be a brief uptick in winds over the lakes Saturday
afternoon. The central Great Lakes will remain in between a broad
high over the Appalachians and a low moving across northern
Ontario/Lake Superior Sunday and Monday which will keep winds on the
lighter side.

&&

DTX watches/warnings/advisories...
Michigan...none.
Lake Huron...none.
Lake St Clair...none.
Michigan waters of Lake Erie...none.
&&

$$

Aviation.....SC
discussion...sf

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