Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 161921
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
221 PM EST Thu Feb 16 2017
Upper heights will build steadily through Friday as mean upper
trough over the northeast CONUS shifts east as deep low pressure
system lifts into the Canadian maritime. The progression of the
upper trough will allow upper ridging to translate eastward over the
area during the next 24-36 hours. This will allow for moderating
conditions on Friday after another cool start early Friday morning.
Expect lows to range generally in the 20s with perhaps a few teens
mixed in from the Saginaw Valley into the Thumb. Southeast flow will
then veer to south on Friday as a warm front lifts north into the
area coincident with the building upper ridge. This will lead to
some north to south disparity in temperatures with locations near
the Michigan and Ohio state line reaching 50 degrees while lower 40s
hold sway over the northern forecast area. Would not be too surprised
to see a 50 degree reading at Detroit as well.
While the upper ridge flattens into a more zonal flow pattern into
Saturday as separate northern and southern stream waves brush by
area in split flow pattern, very mild conditions will prevail. ECM
MOS continues to lead the way on Saturday with temperatures into the
lower 60s metro Detroit south, GFS MOS middle 50s and 12z NAM MOS
right at 60. All temperatures taper back 5 to 10 degrees north and
northeast into the Thumb. Do not plan on any changes at this time
with MaxT grid pretty close to MET MOS guidance ranging from 60
south to 50 far northern forecast area.
With the northern and southern streams split, do not expect any
precipitation as the aforementioned shortwave traverse both north and
south of the central Great Lakes.
A ridge of high pressure sliding over the area will bring very light
winds tonight. Modest southerly flow will then develop Friday and
continue through Saturday as broad low pressure lifts through the
Northern Plains and Central Canada, turning west in the evening. The
strongest winds will be located over Lake Huron, with gusts reaching
just over 20 knots Friday from the south, and 20 to 25 knots on
Saturday from the west.
Issued at 1242 PM EST Thu Feb 16 2017
Band of lower clouds stretched over and just west of terminals at
1700Z will slide eastward over the next few hours, while drier air
entrainment into the area will also cause these clouds to thin and
dissipate. Expect VFR conditions by 20Z. High pressure over the area
will then provide lighter winds and allow for only high clouds into
the evening. Broad troughing extending into the Northern Plains from
low pressure over Canada will lift an elevated warm front through
the area this evening and early tonight. An area of mid-level clouds
will pass across Lower Michigan tonight as this occurs, with little
impact to the terminals.
For DTW...Clouds near 3500 feet will move east while also thinning
over the next few hours. Expect VFR conditions to develop in the 19-
20Z window. Winds will trend lighter and turn more westerly through
the afternoon, then become light and variable in the evening.
//DTW THRESHOLD PROBABILITIES...
* Medium for ceilings below 5000 feet through 19Z today.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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