Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 231141
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
741 AM EDT Thu Mar 23 2017
Dry arctic air mass will retreat to the east coast today as surface
high pressure centers over the Mid Atlantic. Strong warm air
advection is forecasted to wash across the southeastern Michigan
late tonight in response to low pressure organizing over the central
and southern Great Plains. From this vantage point, the forcing for
any longer duration rain event remains low. The reasons include:
strongly anticylonic flow over southeastern Michigan complete with
localized AVA rolling through area in addition to the longwave ridge
axis holding over the central Great Lakes. Therefore, just a
moderate confidence level in any larger coverage of rain showers
with a shorter duration of 3 hours or less. Uncertainty continues
with regards to amount of low level moistening particularly for
Detroit terminals. With the burgeoning warm sector maintained the
low level wind shear group.
For DTW...High cloud will thicken today but dry air keep conditions
VFR with cigs greater than 7000 ft agl. Low confidence exists in
degree of lower troposphere saturation. Continued a low base MVFR
cig after 08Z but it is certainly plausible for prevailing to remain
well above that.
//DTW THRESHOLD PROBABILITIES...
* Medium in cigs falling below 5000 ft after 04z Thursday night.
Issued at 337 AM EDT Thu Mar 23 2017
Large arctic high pressure is centered just east of the state this
morning keeping the coldest and driest air also just to the east.
This is resulting in lows this morning mostly upper teen and low 20s
as opposed to colder as advertised earlier. As this high continues
to slide eastward return flow will bring waa today. The day will
start with plenty sunshine before mid and high level clouds thicken
throughout the day ahead of approaching warm front. Highs today will
do about ten degrees higher then yesterday making it to the low to
mid 40s. Lows tonight will be reached early on in the mid 30s before
slowly rising as warm front lifts quickly through. Not much forcing
with this front other then moderate isentropic lift in the 850-600mb
level resulting in a band of showers that should last for a couple of
hours. Instability is near nil so do not expect any thunder. By
sunrise Friday the warm front should be positioned across the Saginaw
Valley and Thumb where it may lift a bit more north before stalling.
This will allow for very mild air to infiltrate the rest of the
forecast area with highs reaching the 60s most locations with upper
60s near the Ohio border. Dry air in the mid levels should cap off
moist low level resulting in mostly cloudy day and dry for the most
part with lack of any forcing. Exception will be continued shower
across the north closer to stalled front. If any significant breaks
can be made in the clouds 70 could easily be reached across the
Closed low system centered over Oklahoma will gradually weaken as it
drifts towards lower Michigan over the weekend. This will continue
moist mild flow into the state. Another large arctic high will move
across eastern Canada forcing the stalled front across central lower
Michigan to slowly move back southward where it will stay throughout
the weekend providing focus for continued shower activity. The whole
muddled mess should exit the area for Monday. This will be quickly
follow by another wave exiting the Plains which will bring another
chance for showers Monday night and early Tuesday.
Large area of high pressure will build southeastward into the Mid
Atlantic today. As the surface high pushes southeastward, winds will
switch to the southeast and steadily increase. In response, a warm
front will become increasingly organized over the region. The warm
air streaming over the cold Lakes is expected to promote stable low
level profiles, limiting wind speeds over Lake Huron to 25 to 30
knots. Winds will diminish on Friday as warm front stalls over Lake
Huron, and then sinks south as a cold front Friday night into
Saturday, resulting in increasing easterly flow as high pressure
builds over Ontario, leading to long duration easterly flow over the
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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