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000 
FXUS63 KDTX 281051
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
651 AM EDT Tue Mar 28 2017


.AVIATION...

Ongoing shallow cold air advection within a moist low level 
environment has led to widespread IFR stratus with some LIFR/VLIFR 
cigs as well. Some subtle low level drying and cold air advection 
along with daytime heating will gradually lift the cloud bases to 
MVFR, likely late this morning or early afternoon. There will be a 
push of drier air from the north later in the day that will erode 
the stratus deck during the evening. 

For DTW...The gradient will support a steady north-northeast wind 
during the entire day. Boundary layer growth due to daytime mixing 
will sustain the wind speeds around 10 knots. Timing of the lifting 
of cloud bases to MVFR carries some degree of uncertainty, but 
should occur sometime between 15Z and 17Z. 

//DTW THRESHOLD PROBABILITIES... 

* High for cigs below 5000 feet this morning through mid evening.

&&

.PREV DISCUSSION...
Issued at 322 AM EDT Tue Mar 28 2017 

DISCUSSION...

Quiet forecast through the midweek period as high pressure aloft and 
at the surface build into the region. The last of whatever light 
showers can develop over the far southern CWA will move off early 
this morning but only a slow improvement in cloud cover will be 
realized. The surface high currently over Manitoba, will track 
across Ontario and Quebec through the week which will place us in 
the southern periphery of the ridge resulting in drier and cooler 
easterly flow. Expect a cooling trend through Thursday in response 
to this sustained easterly flow. Stronger subsidence aloft due to an 
amplifying ridge ahead of the next southern stream trough will dry 
the column out from the top down. Basically we'll end up with a low 
stratus deck around 2-3kft by this afternoon that should scour out 
from north to south allowing some sun by nightfall. 

Will keep with the cool easterly flow in the low levels on Wednesday 
but a drier airmass will result in plenty of sun through the day. 
Could see some cirrus debris ahead of the next system and also a few 
diurnal cu early in the diurnal cycle before scattering out. The 
next system will be over the southern Plains Wednesday, pinching off 
from the northern jet. Southern jet tries to absorb it but some 
energy in the trough remains tied to the northern jet which isn't 
doing the models any favors. Overall they are pretty well in sync but 
the setup could turn one way or the other pretty quick. As for now 
will go with persistence forecasting with the steady model output. 

The low will lift northeast Wednesday night with good warm air 
advection centered around 5-10kft ahead of it into the region. Low 
level easterly flow from the surface high will hold through the day. 
Looks like the initial rain will stay to our west late Wednesday 
night and Thursday morning as the 850mb jet surges northward over 
Wisconsin. This would all be elevated showers on the lead isentropic 
leaf but gets a little complicated by the right entrance region of 
the northern stream jet max over northern lower. Models are trying 
to light up this eastward extension of the elevated front Thursday 
morning from about Flint northward. Dry air in the lowest ~8kft will 
make it tough for this to reach the ground but will be something to 
watch. Better precip chances come Thursday afternoon as the 850mb 
jet slides over lower MI bringing a surge of better theta E into the 
area. This in conjunction with upper level diffluence and isentropic 
ascent looks to produce a broad coverage of showers across the area. 
There does remain a chance of some mix precip at the lead edge if it 
can get going early enough Thursday morning as dry, cool surface 
layer will wet bulb, but overall think best precip chances will come 
after diurnal heating commences. 

Rain will taper off overnight as the system progresses eastward with 
the last of the showers exiting the area Friday morning. Ridging 
will build back into the region Friday for the weekend. This will 
bring quiet weather and a slight warming trend back to the mid 50s.

MARINE...

Northerly winds will increase during the day as strong high pressure 
expands across the northern Great Lakes. Wind gusts may reach 20 
knots across the southern Lake Huron basin and possibly Saginaw Bay 
where northeast winds will funnel into the bay. The high will expand 
into the eastern Great Lakes by Wednesday. Modest northeast winds 
will be sustained as a result. Low pressure is forecast to lift into 
the Ohio Valley on Thursday before pushing into the southern Great 
Lakes on Friday. This system combined with strong high pressure to 
the north will lead to increasing east-northeast winds Thursday into 
Friday, possibly resulting in the development of small craft 
advisory conditions.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....SC
DISCUSSION...DRK
MARINE.......SC

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