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FXUS63 KDTX 212315

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
715 PM EDT Wed Mar 21 2018


VFR flying conditions will prevail through the TAF period within a 
persistent dry northerly flow. A high coverage of mid level cloud 
will linger tonight, but skies will remain clear across the lowest 
10k ft. Clearing skies then for Thursday under gradually building 
high pressure. Diminishing northerly winds this evening will 
gradually shift to northwest overnight, generally dropping below 10 
knots during this time. Modest northwest winds will remain in place 
for Thursday.  

For DTW...Northeast flow operations favored this evening under 
prevailing northerly winds.  Winds diminishing while slowly shifting 
to northwest overnight.  Winds holding northwesterly /320-330/ near 
10 kts Thursday. 


* None.


Issued at 340 PM EDT Wed Mar 21 2018 


Closed geopotential height anomaly over the Ohio Valley and Mid-
Atlantic has maintained an influence on the wind field over the 
Central Great Lakes today as north northeasterly flow of 20 to 25 
knots has been commonplace. Trailing shortwave and jet energy into 
the rear portions of the upper level low, resulted in a relatively 
strong inverted trough back into portions of western Ohio earlier. 
All forecast information supports this surface trough stripping out 
this evening.

For tonight, low level dry air will become increasingly entrenched 
across the region with sustained northeasterly flow in place. More 
quiet weather. There is probably some question of high and mid cloud 
potential for tonight with modeled RH showing a corridor of some 
saturation advection west to east the latter half of the night. 
However, integrity and transparency of ac/high cloud is very much in 
doubt gauging from upstream cloud this afternoon.   

Sustained northeasterly flow behind the large east coast low 
pressure system will allow for deep column cold air advection over 
southeastern Michigan on Thursday. Not necessarily colder near the 
surface, but degree of cooling in the midlevels will support very 
stable conditions. Differential height rises locally will support 
some increased surface ridging over the state by late Thursday but 
not enough to dissipate the northerly gradient flow. Generally 
preferred MOS with a cooler blend given good amount of insolation. 
Slowly evolving pattern over North America the latter half of the 
week brings a virtual persistence forecast on Friday. Only real 
question is how far the surface high will move eastward. With 
dominant northern Canada surface high staying still, preference is 
for below normal temperatures again on Friday.

Temperatures on the cool side remain through the weekend. Highs in 
the 30s and lower 40s with overnight lows in the 20s. Strong high 
pressure over Canada will continue to dominant the weather pattern 
with northeast to easterly flow at the surface. A low pressure 
system will move out of the plains and into the Ohio Valley on 
Saturday, but current path keep the precip south of the Michigan 
border. So things look to remain dry for the weekend with the high 
pressure in control and a mid/upper level ridge passing over. 

A long wave trough begins to set up across the western US next week 
and will bring the next shot of precipitation to southeast Michigan. 
Precipitation is forecast to arrive Tuesday afternoon. Temperatures 
will also be on the increase to starting Monday and continuing 
through midweek. High temperatures will begin to increase into the 
50s for much of the area by midweek.


Moderate northeast winds will continue through the afternoon hours 
as low pressure departs to the southeast. Gusts 25-30 knots will be 
possible at times, especially across southern Lake Huron. These 
winds will continue to lead to elevated waves and hazardous 
conditions for small craft along the nearshore waters of Lake Huron 
and outer Saginaw Bay into tonight. High pressure will begin to 
build across the region from the upper Midwest tonight allowing for 
the flow to slacken and back more to the north and northwest heading 
into Thursday. Light to moderate northerly flow will continue into 
Friday before veering to the northeast this weekend as low pressure 
passes by to the south.


Lake Huron...Small Craft Advisory until 2 AM EDT Thursday for LHZ421-422-441>443.

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



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