Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 231924

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
324 PM EDT MON MAY 23 2016

High pressure that has been in control of our weather this past
weekend is slowly moving east.  Very dry air mass today as evident
by sudden and large dew point drop late this morning as surface
mixing began.  Dew points away from the large bodies of water went
from the mid 30s into the teens in an hour or two.  With full
sunshine and dry air, temperatures today rose into the mid to upper
70s with slightly cooler temps near the water.  Temperatures this
evening will quickly drop around and after sunset as radiational
cooling will be very strong with such dry air. However, warmer and
moisture air will begin to advect in tonight on return flow behind
departing high, so overnight lows will occur early in the night then
level off the remainder.

Sharp upper level ridge over the Midwest will also slide east over
the Great Lakes tonight then flatten out on Tuesday. This will bring
a warmer and moistening airmass along with plenty of sunshine with
mainly some mid and upper level clouds moving in late in the day
approaching cold front.

As the ridge continues to flatten, a weak cold front will drop south
through lower Michigan Tuesday night to about the Saginaw Valley and
Thumb region by Wed morning.  The lower levels will continue to
slowly destabilize ahead of the front as higher dewpoints advect in
on southwesterly flow however, mid and upper level forcing is very
weak and some opposition as area will be in right exit region of
upper jet while lift from convergence along front will remain weak.
Some shower or thunderstorm development is possible along and ahead
of the front with best chances across the northern portions of
forecast area...mainly north of Detroit.

The cold front will stall in this general area Wed and Wed night.
Again forcing is lacking but instability will continue to gradually
increasing so there will remain a slight chance for a shower or
thunderstorm Wed, especially late in the day with peak heating.

Models indicate a weak shortwave kicking out of the Midwest into the
Great Lakes Wed night which will generate better instability and
lift so expecting more shower and storm activity. Wind field up
through 500mb are not very impressive so just expecting garden
variety like activity.

The area will remain on the active side going into the Memorial Day
weekend as rain and thunderstorm chances hang around.  A series of
low pressures will continue to influence precip chances with a low
moving across northern portions of the Great Lakes region Thursday
through Friday before another low coming up from the southern plains
moves towards the area for the weekend.  Warm temperatures will
continue through the end of the month as highs continue to warm up
into the 80s.



Surface high pressure over the region will bring dry quiet weather
and light winds for the remainder of today and tonight. South to
southwest winds will increase Tuesday into Tuesday night as a weak
low pressure system tracks across the Northern Great Lakes. The
passage of this system will allow a cold front to settle over Lake
Huron late Tuesday night and early Wednesday, flipping winds on the
north side of this boundary to the north. This boundary will then
lift back northward Wednesday night as southerly flow increases. The
presence of this front over the region, and an increasingly warm and
humid airmass, will provide a chance for showers and thunderstorms
through the mid-week period.



The arrival of a warm and humid airmass will bring chances for
showers and thunderstorms Tuesday night into the Memorial Day
Weekend. The best coverage of rain is expected to be late Wednesday
into Wednesday night as a warm front lifts into the area. Rainfall
amounts are expected to vary widely by Wednesday and Thursday, with
heaviest amounts in thunderstorms. Thunderstorms will carry
potential for significant rainfall, with amounts that will likely
exceed 0.25 inches, and even approach 1 inch at times.


Issued at 115 PM EDT Mon May 23 2016


High confidence with VFR conditions prevailing through the TAF
period as high pressure remains overhead through tonight. Only issue
for today will be potential for wind shifts this afternoon due to
the lake breeze. The most likely terminals to be impacted by this
will be in the Detroit corridor. (Already arrived at DET per ASOS.)

High pressure will sink southeast tomorrow as a weak area of low
pressure begins to track across the Northern Great Lakes. This will
bring a modest increase in southwest wind and allow for some cu
development late in the TAF period.

FOR DTW...Terminal Doppler radar shows aggregate lake breeze has
released off the lakes and is progressing east towards DTW. Best
idea on timing to reach DTW is between 18-20Z, with current timing
in TAF at 19Z.

//DTW Threshold Probabilities...

* None


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



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