Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 272245

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
645 PM EDT Tue Jun 27 2017


The departure of a weak mid level short wave and loss of daytime
heating will bring an end to residual showers and diurnal cloud
cover over the next couple of hours. The loss in daytime mixing will
also allow the westerly winds to weaken and slowly back to the south-
southwest. The south-southwest gradient will increase during the
overnight and through Wed morning as high pressure advances to the
mid Atlantic. The deepening of the mixed layer will allow a slight
increase in these winds mid to late Wed morning. Otherwise, the high
pressure system and dry ambient airmass will sustain tranquil
aviation conditions through Wed morning.




Issued at 309 PM EDT Tue Jun 27 2017

Shortwave dropping through back side of mid level trough is clipping
eastern Michigan this afternoon and evening.  Very cold airmass
aloft as this mornings sounding indicate freezing level around 6kft
combined with strong diurnal heating is yielding capes upwards to
around 1k joules producing scattered showers mainly from the Thumb
and Saginaw Valley on north. Expect this activity to continue into
the evening before dissipating around sunset. some light shower
activity could make it down to the Detroit area briefly during prime
heating. Some thunder is possible as -20c is just a mere 16kft above
the surface. After...skies will clear early tonight as surface high
pressure slides by to the south and mid level heights rise. Wednesday
will start off mostly sunny but clouds will begin increasing from
the west during the afternoon as waa around backside of departing
high begins. Shortwave tracking through the upper midwest will spin
up a weak surface low Wednesday that will track east across the
northern Great Lakes. Showers and Thunderstorms will develop over
Wisconsin and spread east-southeast along a strengthening warm front
that will be lifting north through lower Michigan tomorrow afternoon.
Expect the best chance for showers and thunderstorms to occur late
afternoon/evening across the Saginaw Valley and Thumb. This area will
be sensitive to any heavy rainfall after major flooding over the
weekend. Activity shouldn`t last too long and expecting maybe upwards
half an inch. There should be a break in activity after warm front
passage but showers and thunderstorms will return later Wednesday
night as a cold front moves through lower Michigan down to along the
southern border Thursday morning where it will stall as main
shortwave lifts northeast into Ontario.

Thursday should be rather quiet for most of the forecast area as mid
level ridge slides through but showers and thunderstorms will still
be possible especially across the southern two tiers of counties in
the vicinity of the stationary front. Another stronger shortwave in a
broader deepening trough will advance towards the Great Lakes
Thursday night. In response the stationary front will lift back north
as a warm front bringing a chance for showers and thunderstorms
across the area. Temperatures will be more seasonable the next couple
of days.

EXTENDED FORECAST Friday June 30th through Wednesday, July 5th:
Models showing little change in the forecast from yesterday with wet
weather pattern still expected to resume mid-week and continue into
weekend as several waves of low pressure move through SE MI. Chances
of showers/thunderstorms still look to increase by Friday afternoon
and evening with a few showers lingering about for Saturday. Surface
high pressure is delayed until Sunday on new run, along with the
upper level trough. Upper level troughs could still be a bit of a
fly in the ointment triggering scattered showers Sunday through
Tuesday. At present, the vort maxes disappear for Wednesday as high
pressure gets a slightly better footing over the area; translation,
drier conditions and less clouds Wednesday. Temperatures continue to
hold near the seasonal norm through the period with highs in the
upper 70s to low 80s and overnight lows in the 60s.


Moderate westerly winds will hold throughout the afternoon as
diurnal heating over land brings the slight chance to see isolated
showers over the Saginaw Bay, and along the western coasts of the
Great Lakes. Overnight, winds will shift from westerly to more
southwesterly as nocturnal stability acts to keep winds light. High
pressure moving east across the Ohio Valley will act to keep
conditions dry throughout Wednesday and will usher in warmer air
into the region, bringing more stable conditions over the lakes as
gusts remain sub-15 knots. Thunderstorm chances then move in
Wednesday night into Friday as a series of low pressure systems help
to advect warm, moist air into the region.


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



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