Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 121917
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
317 PM EDT Tue Mar 12 2024

.KEY MESSAGES...

- Mild conditions continue Wednesday with above average highs mainly
  in the 60s.

- Minor rain chances arrive late Wednesday and Wednesday night with
  better rain chances Thursday into Thursday night when some embedded
  thunderstorms will be possible.

- Colder temperatures late weekend into early next week with highs in
  the 30s to around 40 and scattered snow showers possible.

&&

.DISCUSSION...

A weak frontal boundary will sag south into the region on Wednesday
and stall into Thursday as low pressure encroaches on the area. This
low pressure will then pass the area Thursday night and allow the
front to shift south into Friday. Temperatures will hold in the mid
40s within west-southwest flow in advance of this front tonight, but
settle back to the upper 30s to around 40 over northern portions of
the forecast area where this front will make inroads overnight. As
the front stalls near the I-94 corridor Wednesday, high temperatures
will be warmest along/south of the boundary (in the middle 60s), but
still reach the upper 50s to lower 60s further north before colder
north to northeast flow caps temperatures during the afternoon.

Minor FGEN forcing will develop during the day Wednesday, and with
decent diurnal heating, expect a few showers to pop up over southern
areas during the afternoon. Better forcing ensues Wednesday night
and especially into Thursday as the aforementioned low approaches
the region. Shower chances will gradually expand north through the
area late Wednesday night/early Thursday morning with likely to
categorical rainfall chances from midday Thursday into Thursday
night as the best forcing associated with the low pressure system
(and parent shortwave) materializes over the area.

Moderate mainly elevated instability with decent mid level lapse
rates (~7C/km) will also bring a chance of embedded thunder during
this late Thursday to Thursday night time frame. Far southern areas
along/south of the low level boundary may fall within the warm
sector for a time which may enhance thunderstorm potential somewhat
as best forcing advances into the area Thursday night. Lingering
showers Friday morning will shift south and east with this system
with some clearing late Friday into Friday night.

A fairly tight temperature gradient sets up Thursday and Friday with
the frontal boundary draped west to east across the forecast area.
Expect highs to range from the 40s to around 50 north to mid-upper
50s south Thursday with progressively cooler conditions expected
into Friday as the front shifts to the southeast with time. Mild
conditions in the lower 50s continue into Saturday as a window of
warm air advection becomes established briefly in advance of the
next approaching shortwave.

This next wave is a rather potent northern stream system that will
drop out of central Canada into the Great Lakes during the upcoming
weekend. This will bring much colder conditions from Sunday into
early next week. Rain/snow showers will be possible on Sunday as the
initial cold front shifts into the region. Several pockets of
additional shortwave energy will then funnel southeast into the
area into the Monday/Tuesday time frame and maintain cold conditions
with a chance of snow showers. Some of this snow shower activity
could become rather vigorous as a secondary stronger cold front
surges through the area late Sunday night into Monday and H85 temps
fall into the -10F to -15F range with time and activate the lake
effect snow shower potential. High temperatures by this time will
hold in the 30s to around 40 with lows well down into the 20s by the
end of this forecast package.

&&

.MARINE...

Southwest winds have ushered in very mild air into the Central Great
Lakes this afternoon, and wind gusts have topped out near, but below
25 knots with the increased low level stability due to the colder
water temperatures.

A weak, dry cold front looks to swinging through Tuesday night, with
modest northwest winds following for Wednesday. A series of low
pressure systems then look to be tracking through the southern Great
Lakes/northern Ohio Valley in the Thursday-Friday time frame. Rain
showers are expected across southern Lake Huron and locations south.
A period of moderate east-northeast winds (~25 knots) are also
expected to develop over central Lake Huron as high pressure
translates east through Ontario/Quebec during the same period.

&&

.HYDROLOGY...

Rain showers and embedded thunderstorms will increase from Thursday
into Thursday night as low pressure tracks into the region along a
stalled frontal boundary. Locally heavy downpours can be expected
with total rainfall amounts averaging around half an inch. Flooding
is not expected with this activity.

&&

.PREV DISCUSSION...
Issued at 1253 PM EDT Tue Mar 12 2024

AVIATION...

SE Mi is firmly in the warm sector of low pressure spanning the
Midwest and Plains states today while Gulf coast high pressure is
only just now allowing limited moisture northward into Texas. This
configuration provides a warm and dry SW flow into the Great Lakes
gusting to near 25 kts this afternoon while supporting VFR with
clouds limited to cirrus coverage through tonight. Boundary layer
stabilization post-sunset promotes a strengthening low level jet and
a few hours of LLWS centered around midnight. Occluding systems in
northern Ontario then pull a cold front into central Lower Mi toward
sunrise which then settles near the Ohio border by Wednesday
afternoon. Limited Gulf moisture return is only able to supply mid
level clouds with the frontal passage resulting in broken coverage of
ceiling above 5000 ft throughout the day.

DTW THRESHOLD PROBABILITIES...

* None.


&&

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

$$

DISCUSSION...DG
MARINE.......SF
HYDROLOGY....DG
AVIATION.....BT


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