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Area forecast discussion 
National Weather Service Detroit/Pontiac Michigan
715 PM EDT Monday Sep 22 2014



Aviation...

//discussion...

There is a region of strato cumulus based between 4k and 5k feet across
the Saginaw Valley and thumb associated with a shallow layer of
moisture traversing the region. This moisture will move east of the
region this evening. This along with the loss of daytime heating
will cause these clouds to quickly erode by or shortly after 00z.
Otherwise...high pressure will maintain clear skies and light winds
through the night.

//Dtw threshold threats...

* none.

&&

Previous discussion...issued 324 PM EDT Monday Sep 22 2014

Short term...tonight

Deep northwest flow actually translating to some modest
moisture advection through tonight...see 850-700 mb Theta-E/precipitable water
fields...which has been able to produce a swatch of clouds across
the western Great Lakes. However...with the loss of daytime heating
and main push of the moisture remaining north of Southeast
Michigan....planning on going with mostly clear/clear
forecast...with mins falling into the low to middle 40s...in line with
latest guidance. There is a low chance of some shallow fog
developing late tonight...but chose to leave mention out of the
zones.

Long term...

Starting Tuesday and into Wednesday...upper level ridging will
continue to hold bringing tranquil conditions over the area. This
ridge along with surface high pressure will allow for mostly clear
skies during this period. Temperatures remain pretty steady during
the week...but even with full sun the cooler airmass will keep temperatures
right around normal for this time of year. Highs top off in the
lower 70s with lows cooling off to around 50f. Under clear skies
and light winds. The only upcoming concern will be the potential
for radiational fog to develop during the early morning hours.

Anomalous upper ridge will continue to hold over much of the eastern
Continental U.S. For the remainder of the forecast...likely ensuring tranquil
weather continues with above normal temperatures. Only source of
uncertainty may arise with the upper low currently over
ID/WY...though there is good agreement that it will either be
absorbed by the northern stream well north of the Great Lakes or be
unable to penetrate the strong upper ridge.

Marine...

Winds will ease through the remainder of the day as high pressure
builds in over the region. High pressure will hold steady over the
area through the week bringing dry and quiet conditions over the
marine areas.

&&

DTX watches/warnings/advisories...
Michigan...none.
Lake Huron...none.
Lake St Clair...none.
Michigan waters of Lake Erie...none.

&&

$$

Aviation.....SC
short term...sf
long term....ss/dt
marine.......ss



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