Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 221934

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
334 PM EDT Thu Mar 22 2018


Dry, but cool weather conditions continue today with a high pressure
in control. Northerly winds, which will lighten up today compared to
previous days, will help keep high temperatures below normal this
afternoon. The cool north winds off the waters of Lake Huron will
hold the temperatures across the Thumb in the 30s, while the rest of
the area will reach into the low to mid 40s. A vorticity max will
drop down through the Great Lakes tonight with an associated weak
cold front. This front will have little impact other than bringing a
slight increase in clouds to the north and a subtle wind shift to the

High pressure will strengthen through tomorrow with center of the
high located north of Lake Superior. The mid/upper level ridge will
drift slightly to the east towards the western Great Lakes.
Conditions tomorrow will be very similar to what we see today. A
more pronounced northeast flow will again keep temperatures several
degrees cooler across the Thumb. A weak pressure gradient will keep
winds on the lighter side again for Friday with overnight lows
dipping into the 20s.

A short wave and surface low will move out of the plains on Saturday
with the center of the surface low riding along the TN/KY border.
Southeast Michigan will remain dry with the precipitation shield
staying south of the Michigan border. Being caught in the middle of
the Canadian high that will slide east over Quebec and the low to
our south will result in a tightening pressure gradient. The
increasing northeast winds will lead to a brisk wind on Saturday
with temperatures remaining in the low 30s to low 40s during the

Strong high pressure will keep cool, dry easterly flow in place on
Sunday as highs remain in the low 40s. A change in the weather
pattern will then commence early next week as an upper ridge axis
finally shifts eastward across the region on Monday. Increasing
southerly flow on Monday will advect warm, moist air northward
across the region as highs rise into the low 50s. A disturbance
ejecting northeast from longwave troughing over the Western US will
then bring the next chance for widespread precipitation to the
region starting early Tuesday and continuing through early
Wednesday. Precip type with this system looks to remain all rain as
highs/lows rise into the 50s/40s on Tuesday and Wednesday.



Cold north to northwest wind will be just strong enough to keep
waves elevated over southern Lake Huron today and small craft
advisories remain in effect for all nearshore zones south of Port
Austin. A backdoor cold front will then move through the region
tonight. Dry conditions are expected with the front but it will be
able to reinforce cold air and northerly flow tonight through Friday
morning. The resulting higher waves will mainly affect the Port
Austin to Port Sanilac nearshore zones before diminishing later
Friday morning. However, the diminishing trend will be short-lived
as northeast flow is expected to strengthen Friday night due to
building high pressure over northern Ontario and as the next low
pressure system moves into the Ohio valley Saturday. The renewed
northeast wind will likely require small craft advisories for all
Lake Huron and Lower Michigan marine areas into Sunday.


Issued at 223 PM EDT Thu Mar 22 2018


Very dry northwesterly flow will persist over the central Great
Lakes throughout the TAF period. Very little moisture to speak of as
a period of midlevel isentropic downglide occurs late this afternoon
then another period of low-midlevel isentropic downglide late
tonight. Surface winds have overachieved so far today with northwest
ranging 10 to as high as 25 knots. Heavy diurnal component to the
mixed layer, decaying at/around sunset. No strong signal in model
data for lower level boundary layer cloud late tonight. Best support
should miss to the east as a shortwave digs southward over Lake
Huron tonight.


* None.


Lake Huron...Small Craft Advisory until 10 AM EDT Friday for LHZ441-442.

     Small Craft Advisory until 4 PM EDT this afternoon for LHZ443.

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



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