Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 221931

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
331 PM EDT SUN MAY 22 2016


Omega-block pattern covering the CONUS will slowly slide east over
the next few days, shifting the amplified upper ridge over the Upper
Midwest and Western Great Lakes into Michigan on Monday. At the
surface, this will settle the center of surface high pressure over
Lower Michigan tonight and Monday. Dry air and subsidence through
the column will allow for clear skies, with winds tomorrow dominated
mostly by lake-breeze effects. A slow warming trend will also occur,
after a chilly night tonight. Good radiational cooling conditions are
expected to set up allowing temperatures to fall into the mid/upper
30s to mid 40s. This will bring potential for patchy frost in the
coldest locations, with primary threat along and north of the I-69
corridor. Temperatures will only be favorable for a few hours
overnight, and will keep coverage mention at patchy. Good insolation
and slightly warmer temperatures profiles should bring max temps
back up into the mid 70s tomorrow, with locations near the
lakeshores remaining cooler as winds turn off the lake. Relative
humidity tomorrow will also fall quiet low as dewpoints reach into
the 30s across a wider area than observed today. This will lead to a
very dry day, as minimum humidities fall around 25 percent for most
locations away from the lakes.

Upper energy ejecting out of the western trough will ride through
the Northern Plains and central Canada (including Ontario) Monday
night and Tuesday, flattening the upper ridge over the area. This
will gradually allow the mid-level subsidence inversion to erode and
instability to build, in part as a weak low-level jet transports
warmer air into the region late Monday into Tuesday night. Gulf
moisture will meanwhile slide into the area as the what is left of
the western flank of the upper ridge cascades over Michigan. An
initial surface trough axis and associated cold front will work
across the area Tuesday night as the upper energy rides to our
north. This will provide a focus for showers and thunderstorms. It
appears, per model forecast soundings, that temps may still be too
warm in the mid-levels (600mb and above) Tuesday afternoon and early
evening to support convection, even closest to the front over the
Saginaw Valley. Kept the forecast for Tuesday dry, with increasing
chances for showers/thunder in the late evening and overnight.
Deeper mixing, plenty of sunshine, and warm air advection should
allow temperatures to climb to around 80 on Tuesday.

Wet weather pattern is scheduled to arrive late Tuesday as developing
low pressure over the midwest and plains ushers in a warm/moist
airmass. Instability overnight Tuesday and Wednesday will allow for
showers with a chance of thunderstorms. Thunderstorm probability is
likely by Wednesday night through Thursday morning over most of
Southeast Michigan. Since it is still more than a few days
out...timing may need minor adjusting as the system progresses.
Brief moderate to heavy down pours associated with stronger showers
seems a reasonable expectation. Chance of showers/thunderstorms will
persist through the weekend. Severe thunderstorms are not expected
at this time. Temperatures during this period are progged to
gradually rise into the low warm...wet and muggy on the way.



The upper level pattern over North America is expected to support
favorable marine weather conditions in the central Great Lakes
region throughout much of the upcoming week. Modest northerly flow
in the 15 to 20 knot range today is expected to evolve into
southerly flow by late Monday. Very weak southerly flow will then
persist over southern portions of the Great Lakes until the holiday
weekend. The next potential for a greater coverage of shower
activity begins Wednesday when a chance for thunderstorms will also


Issued at 122 PM EDT Sun May 22 2016


The onset of diurnal heating and growth of boundary layer this
morning has allowed fresh mixing to access residual higher momentum
that existed in the midlevels. As the pbl mixing now matures during
the afternoon...the magnitude of the windgusts should lessen with
time. Otherwise...the combination of modified polar air with
increasing midlevel heights will support stable and cloud free
conditions throughout the forecast period. The exception is the few-
sct 050 cumulus that is now advecting south of the DTW terminal.


FEW-SCT 050 cumulus will push south of the DTW airfield during the
first hour or two of the period. No aviation weather is then
expected through the remainder of the period.

//DTW Threshold Probabilities...



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



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