Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 130458
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1158 PM EST Thu Jan 12 2017
The reinforcing surge of cold air was effective at clearing out the
low clouds over lower Michigan during the evening. Moderate westerly
wind will settle back in speed and back more toward the northwest as
high pressure continues to build into the Great Lakes during the
night. The northwest direction will help confine closer to the
shoreline any stratocu from Lake Michigan which will also be limited
by the dryness of the incoming air mass. This will be monitored but
the forecast will be on the optimistic side for low cloud coverage
underneath thickening high clouds during the morning. VFR will then
continue through afternoon as low level wind continues to diminish
and veer toward northeast into Friday evening.
//DTW Threshold Probabilities...
Issued at 321 PM EST Thu Jan 12 2017
Arctic high pressure will build into the area from tonight into
Friday. While the main center of this high pressure then shifts east
Friday night, extensive surface ridging will remain in place from
the Great Lakes west into the northern plains through the upcoming
weekend. In general, this will mean colder and drier conditions over
the next several days.
Despite the presence of this high pressure near the surface, an
extensive subtropical plume of moisture will be in position over
the southern CONUS during this time frame as southern stream jet
energy lifts out southwestern CONUS upper trough/low and rides into
confluent upper level flow over upper midwest and Great Lakes. With
the northern fringe of this plume residing over the forecast area,
expect partly to mostly cloudy skies over the next few days.
A weak northern stream shortwave will also brush the area on
Saturday. This will bring the only small chance of precipitation in
the 2 to 3 day forecast period as this wave, combined with moisture
from the northern edge of the subtropical jet, leads to extensive
cloudiness with the possibility of a few bands of light snow where
the northern/southern streams interact. As this northern stream
shortwave races east Saturday night, ensuing subsidence will most
likely push the subtropical moisture far enough south to allow for
more sunshine on Sunday.
Generally speaking, expect the high temperatures of 25 to 30 on
Friday to edge up only a few degrees over the weekend. Meanwhile,
cloud cover and a lack of significant snow pack will maintain low
temperatures in the 10 to 20 degree range area-wide.
A broad surface high pressure system will push east from the
Northern Central Plains on Sunday, keeping conditions quiet as
temperatures peak in the lower 30s for a daytime high. The next
chance for precipitation will enter Michigan early Monday and will
continue throughout Tuesday, as low pressure from Texas/Oklahoma
pushes northeast into the Great Lakes region. As the low travels
into the region, it will usher in 850 and 925 mb temperatures that
are above freezing, while surface temperatures lag behind. As a
result, there will be a chance to see a wintry mix/freezing rain for
the onset of the precipitation, before a transition to all rain by
Monday afternoon/evening. Strong WAA will keep temperatures above
normal throughout Tuesday, with highs peaking in the upper 40s to
lower 50s, which will continue to produce an all rain solution. The
chance for rain will diminish significantly by Wednesday as low
pressure pushes off into New England. Current thinking is that the
later half of the week will remain relatively dry, as GFS/ECMWF/GEM
models hold off on QPF, however, long range MOS guidance brings
slight PoPs to Michigan on Thursday and Friday. As a result, keeping
lower end chances for precipitation for the end of the week.
Overall, long range models have started to converge regarding the
timing on Monday`s system, which includes the possibility of seeing
more of a wintry mix before a transition over to all rain.
The pressure gradient increases tonight as high pressure ridging
moves in. Westerly winds will continue overnight and turn slightly
to the northwest on Friday as high pressure ridging moves in. Winds
will increase as the pressure gradient tightens tonight with
westerly winds of 35 knots or greater being likely for northern Lake
Huron. Gale warning will be in effect tonight for the northern Lake
Huron basin between 00Z and 09Z. Surface high pressure then builds
eastward into the region and will allow winds to subside by midday
Friday and continuing through the weekend.
Lake Huron...Gale Warning until 4 AM EST Friday FOR LHZ361-362.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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