Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 182305

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
705 PM EDT Wed Oct 18 2017


Clear sky will persist through the evening as gusty southwest wind
subsides with the loss of surface heating. The boundary layer
decoupling will allow a moderate low level jet to develop through
the night. Model soundings indicate LLWS averaging around 30 kts
which is marginal for inclusion in the forecast. Surface gradient
wind will average 5-15 knots before the upstream cold front arrives
Thursday morning. Satellite imagery indicates an associated band of
mid and high clouds over the western Great Lakes which is expected
to move over SE Michigan overnight. Model guidance does indicate
some lower clouds will be possible, mainly in the MBS area, as the
front moves through the region. Considering the very dry low level
conditions, expect any ceiling to remain VFR during the morning and
early afternoon while the front weakens with time.


* None.


Issued at 308 PM EDT Wed Oct 18 2017


Southwest gradient and full insolation once again supporting warm
temperatures this afternoon. Boundary layer will remain mixed
through tonight as the approaching front attendant to the cyclone
over central Canada approaches from the west and ensures overnight
lows are contained to values no lower than this morning`s obs. Cold
fropa early Thursday morning will occur uneventfully given SE
Michigan`s removal from dynamic forcing and dry antecedent
conditions. Minor suppression of the thermal field will primarily
influence the northern half of the CWA, where highs will be a few
degrees cooler than today in the mid 60s. Near 70 again across the
south. Return flow will quickly get underway Thursday night into
Friday as high pressure becomes reestablished over the Appalachians
in response to pattern amplification driven by an surging NPAC
energy out west. Highs Friday once again near 70 under cloudless

The pattern for Saturday and most of Sunday will remain largely
unchanged from that of the late half of the week, with surface and
upper ridging leading to dry conditions with above normal
temperatures in the low 70s.

The energy that lead to the digging trough in the western CONUS and
amplified ridge for SE Michigan most of this week will begin to
impact us late Sunday into Monday. Ample moisture ahead of the
surface front will lead to a decent chance for showers overnight
Sunday. Cooler air will begin to filter in behind the front; highs
Monday into the mid 60s and a lingering chance of showers.

Following this front on Tuesday into Wednesday, an upper trough will
dig through the Great Lakes and much of the eastern CONUS. This will
lead to the coolest temperatures of the season so far, highs falling
to the upper 40s and lower 50s by Wednesday, with generally
unsettled conditions and a chance for showers through midweek.


Small craft advisories across the Saginaw Bay will persist this
afternoon and likely overnight as southwest winds continue to gust
between 20 - 25 kts, isolated 30 kt, across the bay. Winds and wind
gusts will start to relax throughout Thursday morning as the
pressure gradient weakens, which will hold wind gusts to sub-20
knots through the remainder of the week. Additionally, high pressure
will hold steady through Saturday, bringing relaxed waves over the
bay and shorelines, along with copious amounts of sunshine.




Lake Huron...Small Craft Advisory until 10 AM EDT Thursday for LHZ421-422-441.

Lake St Clair...NONE.

Michigan waters of Lake Erie...NONE.




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