Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 240733
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
333 AM EDT Tue Apr 24 2018

.DISCUSSION...

Weak radar returns are attempting to work their way northward into
lower Michigan early this morning, but are struggling to produce
much in the way of precipitation at the moment with resident dry
airmass. These showers are associated with a large upper low
currently moving through the TN Valley. As this low slowly slides
east towards the Central Appalachians, it will open up and begin to
merge with a northern stream wave as it swings across the upper
Great Lakes through mid-week. The resident dry airmass will
eventually moisten up the mid and lower levels as moisture is
advected into the region under southerly flow. Precipitable Water
values increase to around an inch across much of the area by 12Z
this morning. Height falls along with some mid level forcing will
support increasing rain chances this morning and into tonight. This
event will feature likely PoPs with low QPF as showers are expected
to remain light and scattered in a way that any one location will
also see dry conditions throughout the day.

The mid/upper level shortwave trough will begin digging through the
western Great Lakes tonight into tomorrow morning bringing greater
height falls. However, the deeper moisture will also be pushed out
of Michigan with decreasing Precipitable Water values and surface
dewpoints by 06Z tonight while a surface cold front progresses
south through Michigan as well. The front will help keep some rain
chances in through the overnight hours with rain showers remaining
light.

The evolution of this trough looks like it will close off tomorrow
over the central Great Lakes but keep a somewhat progressive track.
This will likely lead to precipitation coming to an end by tomorrow
morning. Recent Euro solution still wants hold precip into tomorrow
afternoon, but is the outlier. Cold pool assoicated with this trough
will move in by tomorrow afternoon and drop high temperatures into
the lower 50s inland and mid to upper 40s towards the lakeshores of
the Thumb.

Mid/upper ridge and surface high pressure will build across the
region tomorrow night into Thursday. Post frontal dry conditions
will help scatter out clouds and allow for good radiational cooling,
which will result in overnight temperatures tomorrow dropping towards
freezing in the mid to lower 30s for much of southeast Michigan. On
the plus side, sunny skies on Thursday will help high temperatures
rebound back into the upper 50s and low 60s. Another trough digging
through central Canada on Friday will send another cold front through
Michigan on Friday and bring quick passing line of showers before
another post frontal surface high arrives. Fairly calm weather for
the weekend with cooler northwest flow mitigating a strong warm up.
High temperatures look hold in the 50s.

&&

.MARINE...

Scattered to numerous rain showers will spread northward across the
central Great Lakes today and tonight. The moisture is streaming
northward from the Tennessee Valley low pressure system and ahead of
a weak cold front moving into the western Great Lakes. The front
will sweep the rain eastward early Wednesday and be followed by
moderate north wind into Wednesday evening. Light and variable wind
is projected to turn north over all marine areas by sunrise and
quickly increase to gusts around 25 knots Wednesday morning. Small
craft advisories are likely for outer Saginaw Bay and southern Lake
Huron due to both the wind and waves building in excess of 4 feet
through Wednesday afternoon into Wednesday evening. Wind and wave
conditions then diminish overnight through Thursday as high pressure
builds into the region. The next cold front remains on track to
arrive Thursday night into Friday and is also projected to be on the
weak side in terms of both rain and wind potential.

&&

.PREV DISCUSSION...
Issued at 1156 PM EDT Mon Apr 23 2018

AVIATION...

Moisture will gradually increase from the south overnight with
occasional sprinkles overspreading the area as low pressure lifts
through the Tennessee Valley. MVFR conditions will then develop on
Tuesday with the continued increase in moisture. Showers will be
more prevalent as well as this low lifts closer to the area and a
northern stream shortwave adds to the overall upper support. May
even see IFR conditions by afternoon/evening as decent deformation
sets up over the area.

For DTW...Sprinkles will through the area overnight with periods of
light rain expected through Tuesday. MVFR cigs will be possible by
Tuesday morning (possibly dropping to IFR Tuesday afternoon).

DTW THRESHOLD PROBABILITIES...

* High for ceilings aob 5000 ft after 11z Tuesday.

* High for rain as precipitation type.


&&

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

$$

DISCUSSION...AA
MARINE.......BT
AVIATION.....DG


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