Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 151410 AAA

Area Forecast Discussion...UPDATED
National Weather Service Detroit/Pontiac MI
1010 AM EDT Thu Mar 15 2018


As of 1010 AM EDT...Current forecast remains on track with just a
few minor updates based on the latest trends in observations. Mostly
clear skies to start early this morning will give way to increasing
cloud cover as boundary layer stratocu fills in across the region in
response to a surge in low-level moisture from the lake aggregate
plume and a passing weak midlevel shortwave. This wave, coupled with
daytime heating, will be enough to squeeze out some flurries from
time to time, with no accumulation expected. Some more persistent
light snow showers off Lake Huron will be possible over the
northeastern Thumb with a few tenths of accumulation possible, but
the bulk of this activity will remain offshore with a west/northwest
wind component. High temperatures today will top out in the 30s, but
breezy conditions up to 25 mph at times will still make it feel on
the chillier side for March.


Issued at 648 AM EDT Thu Mar 15 2018


Persistent cold air advection through the day under northwest winds
combined with diurnal mixing will sustain a fairly deep mixed layer.
This will support occasional gusts at or just above 20 knots through
the afternoon. Diurnal mixing will act upon low level moisture
funneling into Se Mi from the northern Great Lakes this morning,
leading to an expansive strato cu field through the afternoon. Per
model soundings, bases are likely to fall into the 3500 to 5k ft

For DTW...Cold air advection should support a gusty northwest wind
during the morning. Wind direction is expected to back slightly more
toward the west in the 18-20Z time frame.


* Medium in ceilings at or below 5000 ft this afternoon and evening.

* Low in crosswind thresholds being exceeded this morning and early

Issued at 321 AM EDT Thu Mar 15 2018


A surface trough will continue to slide south through Michigan this
morning along with a trailing cold front. This will result in an
uptick in winds out of the northwest with gusts to around 25 mph
during the day. Also dropping south will be slight increase in low
level moisture that will bring more cloudy conditions. Weak cold air
advection will come with the passing of this front and expect high
temperatures to remain below average in the 30s. Locations to the
north across the Tri-Cities and the Thumb will be in the low 30s
while locations to the south of I-69 will be in the mid to upper
30s. The increased low level moisture brings the possibility to see
light snow showers/flurries across parts of southeast Michigan
today. However, the presence of a surface dry layer and lack of
deeper moisture will make it a struggle to see anything more intense
than flurries reach the surface. Best shot at seeing any appreciable
light snow will be towards the Thumb and Lake Huron shoreline where
the northwest winds will have a little extra moisture boost and
there will be slightly colder low levels.

Troughing over the northeastern CONUS continues to keep cold
northwest flow over southeast Michigan into tonight. Light snow
showers remain possible along the Huron coastline into the early
part of tonight. Given the more WNW flow, expect any heavier snow
showers to remain off the coast. Though, a few glancing showers
could produce some minor accumulations. Much drier air will begin to
 shut off any activity after midnight as a surface high pressure
dropping out of Canada begins to take hold. Clearing skies will
allow overnight temperatures tonight to drop slightly lower into the
teens for most locations.

Surface high pressure and weakening ridge will keep dry conditions
going through Friday. Winds will be on the downward trend through
the overnight time frame tomorrow and be on the lighter side by
Friday afternoon. Remaining cold air will keep high temperatures in
the 30s for one more day. The broad trough over the northeast begins
to loosen its grip a little by the weekend as a weakening low
pressure coming out of the Central Plains slides through IL/IN/OH.
This will provide a subtle push of warm air advection bringing
temperatures up into the 40s for most locations. The exception being
the Thumb where temperatures stay in the upper 30s. Precipitation
chances that will accompany the weakening low pressure look to
remain south of the Michigan border at this time. If low pressure
takes a more northerly track, some of the southern counties may see
an increase in precipitation chances for Saturday. On Sunday, the
Thumb finally gets into the 40s with the rest of southeast Michigan
under mostly sunny skies while a ridge builds across the central

The next low pressure system is forecast to push through the central
plains and into the Ohio Valley early next week. This will bring
increased precipitation chances to the southern portions of the
area. Still some differences in models in regards to the exact track
of this system, so confidence remains low at this time on how
rain/snow chances will play out. The low will also result in low
level northeast flow, which will draw some cooler temperatures
southward and lower high temperatures slightly for early next week.
General daytime highs will be in the lower 40s and upper 30s.

MARINE...A push of colder air under northwest winds will advance
across lake Huron this afternoon and evening. Although over-lake
mixing depths will not be too terribly high, there remains high
probabilities of wind gusts around 30 knots across the open waters
of Lake Huron. A ridge of high pressure will extend across Lower Mi
on Friday. This will result in a steady weakening of the winds as
they back toward the west. A broad region of high pressure will
linger over the region through the weekend, leading to generally
light winds.


Lake Huron...Small Craft Advisory from 8 PM this evening to 4 PM EDT Friday for

     Small Craft Advisory until 4 PM EDT Friday for LHZ421-441-442.

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



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