Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 171935

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
335 PM EDT Sat Mar 17 2018


The central Great Lakes will be influenced by a high amplitude upper
level ridge and its remnants in the coming days. Evolution of
pattern late this weekend is one for the ridge to break down as
fresh jet energy becomes reintroduced in the southern stream just
south of Arizona. Despite this occurring, model data is convincing
in its solution for a broad area of upper level confluence directly
over Michigan right through early part of next week. Thus, a pattern
of deep column stability and surface ridging is favored.

Tonight...Innocuous surface low pressure center is forecasted to
propagate southeastward within the mean flow, tracking directly from
Lake Superior at 06Z down through the Northern Lake Huron basin by
12Z Sunday. Interesting little feature with virtually no tangible
mass field support, rather the surface low appears to be some
reflection of a midlevel warm advection push along a respectably
strong corridor of midlevel convergence. No precipitation, no clouds
anticipated. Guidance arrived a little high with regards to minimum
temperatures tonight and appears tied to the increasing gradient
flow to the immediately south of the surface low center. Still
prefer the inherited guidance with little to no wind and clear
skies. Good bet for temperatures to nosedive a good amount this
evening, particularly over the snowpack in the Thumb, before
steadying out and rising late for much of the area.

Sunday...Models show surface ridging in control with full sunshine.
Classic early springtime stability. Another day of moderation, 850mb
temperatures a 2-3 degrees C warmer than Saturday, should allow
temperatures away from the larger bodies of water to warm to near 50
degrees. Lack of gradient flow, will then set the stage for an
interesting evening release of the marine layer down through Lower
Michigan. Will see a lake breeze type front move through the area
and knock temperatures back Sunday evening and Sunday night.

Monday...Increasing subsidence following in behind the exiting
synoptic right entrance region to upper level jetstreak will result
in increasing anticyclonic flow trajectories across the central
Great Lakes. Cold air advection Monday with be impressive as 850mb
temperatures at/around 0C will drop into the -3 to -9C range already
by Monday afternoon. Another chilly day with wind chills strugglign
to climb out of the 20s in many areas.

High pressure centered over Ontario and James Bay will keep much of
the extended forecast period quiet for SE Michigan. 850 mb thermal
trough and light NE flow around the high will keep temperatures
below average through next week. Tuesday high temps will reach the
mid 30s across the region with the exception of the Thumb where flow
off the cool Lake Huron will prevent highs from making it above 30
degrees. A gradual modification in this air mass over the course of
the week will bring highs to the low to mid 40s by Friday. Dry
conditions with light winds will characterize the week.

The highest chance for precipitation in the extended looks to be
next Saturday as a center of low pressure tracks to our south over
the Ohio Valley. The potential for snow currently exists as lower
Michigan looks to remain on the cold side of this system; will
monitor trends over the next week to see how the system evolves and
how much cold air and moisture it is able to tap into.



Moderate northwest flow will become fresh to strong out of the
northwest late Sunday night through early next week. The persistent
onshore fetch will build significant wave heights to several feet in
the nearshore zones of Lake Huron and potentially the Michigan
waters of Lake Erie Monday and Tuesday. Small craft advisories may
be needed during this time.


Issued at 1226 PM EDT Sat Mar 17 2018


SKC with winds light northeasterly to variable wind today becoming
calm to variable tonight.


* None.


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



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