Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 290706
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
306 AM EDT WED JUN 29 2016

.DISCUSSION...

High pressure will settle into the western and central Great Lakes
today before shifting south into the Ohio Vally early on Thursday.
Large-scale subsidence associated with the high and shortwave
ridging aloft will bring mostly clear skies today and tonight. After
a chilly start to the morning, dry airmass and sunshine will allow
max temps to rise back into the 70s and even near 80 from Detroit
southward. (5 to 10 degrees warmer than yesterday). Excellent
radiational cooling will lead to a chilly night once again, with low
temperatures falling into the mid/upper 40s to low 50s most areas,
and upper 50s in the Detroit heat island.

Upper shortwave over Manitoba/Saskatchewan will pivot down around
low pressure near Hudson Bay, swinging across Michigan late Thursday
through early Friday. This will push a surface trough and cold front
across the state Thursday night, providing the only chance for
rainfall in the 7-day forecast. Although cooler air aloft looks to
start arriving Thursday afternoon, GFS/NAM model forecast soundings
do not show it will be sufficient enough to erode the cap until 00Z
or later. Moisture also looks to remain fairly meager through about
this time as well, and have kept the forecast dry through 00Z/8PM
Thursday. Sunshine will be prevalent for the first half of the day
before clouds start to work in from west to east. This, better
mixing, and H850 temps rising to 12-14C will result in max temps in
the upper 70s to low 80s.

A solid shot of quick but deep layer forcing looks to accompany the
front overnight as PVA and right entrance region help surface trough
and cold front. Moisture (theta-e axis) looks to pool just ahead of
the frontal boundary, with PW values rising to between 1.0 and 1.5
inches. Instability looks limited however, which should temper the
response from lift and moisture. This does not look like an overall
good chance for meaningful rain as duration of moisture/lift look
confined to at most a 6 hour window, likely shorter per model cross-
sections, and we must first overcome the dry airmass already in
place. Model QPF of more than 0.25 inches looks overdone. Frontal
passage looks to occur across Southeast Michigan during the late
overnight hours through mid-morning on Friday. Chances for showers
and perhaps a thunderstorm will therefore linger into the early part
of Friday for the eastern portion of the forecast area before drier
air and subsidence behind the mid-level trough work into the area.

Surface high pressure will slowly rebuild into the area for the
holiday weekend, yielding higher confidence for dry weather and
allowing max temperatures to warm back into the low/mid 80s by the
Fourth of July. Surface high center will shift east for Tuesday and
Wednesday as upper heights build as an extension of strong upper
ridging over the southeastern U.S.. Latest guidance suggests
temperatures warming back up into the upper 80s to near 90 by
Wednesday.

&&

.MARINE...

High pressure will settle over the Great Lakes today through tonight
and bring favorable marine conditions to Lake Huron through western
Lake Erie. The next cold front is then expected to move into the
region Thursday night and bring a pattern of showers and possibly a
thunderstorm. Northwest winds will ramp up again to moderate speed
through Friday but are not yet projected to reach small craft
advisory criteria. Another round of high pressure will be in place
over marine areas by Saturday.

&&

.PREV DISCUSSION...
Issued at 1205 AM EDT Wed Jun 29 2016

AVIATION...

Mainly clear skies and light winds will hold serve over the
Southeast terminals through today.

For DTW...North/Northwest winds should stay light enough to allow
for southerly flow operations.

//DTW Threshold Probabilities...

* None


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

DISCUSSION...HLO
MARINE.......BT
AVIATION.....Mann


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