Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 161732

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
132 PM EDT Tue May 16 2017


Subsidence from upper ridging and good mixing within a fairly dry
airmass will limit cloud cover to just some passing high clouds for
the remainder of today, with some mid clouds filling in from FNT
north overnight. Stronger south-southwest flow will develop behind a
warm front this afternoon, with gusts looking to top out in the low
20s. Low-level jet will become positioned overhead tonight,
providing low-level wind shear as a core of 40-45 knots winds slides
in between 1500-2500 feet. Stronger southwest winds within the mixed
layer tomorrow will provide gusts of 30-35 knots.


* None


Issued at 257 AM EDT Tue May 16 2017


Convection translating through the area this morning marks the lead
edge of the warm front poised to lift through the CWA during the
day. In the very near term, waning instability will limit convection
to nothing more than occasional thunder and perhaps isolated pea-
sized hail. South of the warm front, highs ranged from the mid to
upper 80s across much of Illinois yesterday with temps touching 90
degrees in Iowa. Advection of this airmass into Se Michigan will
commence as winds veer behind the passing warm front this morning.
Marine-modified flow north of the front will impede its progress in
the Thumb for some or all of the day, prompting a more conservative
forecast there. Elsewhere, mid 80s (low 80s along the glacial ridge)
seem a sure bet. Could certainly see favored locations in Detroit
Metro and Saginaw Valley reach upper 80s, especially if clearing of
clouds takes place more quickly than forecast.

Southwest flow will take hold of the entire CWA by tonight at the
latest as the warm front pushes north in advance of the deep trough
ejecting into the Great Plains. Character of the resident airmass
will remain largely unchanged into Wednesday, but passage of the
upper ridge axis will support slightly deeper mixing heights. In
addition, strengthening southwest flow will support highs in the mid
or upper 80s to engulf the entire area, including the Thumb.
Dewpoints will remain low, around 60, leading to heat indices at or
slightly below actual temperatures both Tues and Wed.

Increasing clouds on Thurs will suppress temps by a few degrees, but
low 80s still expected areawide. Passage of the mid-level wave over
the Straits will provide a a low chance for late afternoon
convection within the prefrontal trough. Degree of instability will
likely be mitigated by prominent capping, which is expected to limit
any severe threat. Temps will fall into the upper 50s and 60s in the
wake of the cold front for Friday.


Southerly flow will then increase today as a warm front lifts north
through the area. Showers and thunderstorms will likely accompany
the warm front, particularly over Lake Huron. While south-southwest
flow will gust to around 20 knots by late today, the increasingly
warm air will create a stable layer over the cooler waters of the
Great Lakes. The highest gust potential, reaching near 25 knots,
will exist along the immediate shoreline on Wednesday and Thursday
as decent gradient flow leads to gusty conditions over the land. No
headlines are anticipated at this time.


Scattered showers and thunderstorms will cross the area this morning
as a warm front lifts through lower Michigan. The best focus will
remain north of the M-59 corridor where a MCV associated with MCS,
currently located east of MKG, will track. Locally heavy rain will
bring one quarter to one half an inch of rainfall to some locations,
especially over the northern half of the forecast area. Flooding is
not a concern.


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



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