Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 211914

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
314 PM EDT Sat May 21 2022


Showers will increase late this afternoon as a weak MCV from
morning convection crosses the area. This activity will generally be
rather little and weakening with time as this area lifts into SE
lower Michigan. A more concentrated area of showers/thunderstorms
will evolve over the Ohio Valley region with the northern edge
brushing southern portions of the forecast area from late afternoon
into early evening. Additional showers and possibly a few storms
will then expand across the area overnight as an area of PVA shears
northeast into the area around the base of an upper trough to the
west of the region. This period of showers will likely be the most
appreciable over the coming 24 hours and will linger into part of
Sunday morning before a stubborn cold front finally sweeps east
of the region with the help of this vorticity lobe.

Drier and cooler conditions are expected midday Sunday into Monday
as high pressure builds into the area behind this cold front and
brings a expanding area of subsidence to the central Great Lakes.
Temperatures will settle back into the lower to mid 60s for highs
during the late weekend/early work week period. These generally dry
conditions will likely hold into Tuesday as the high pressure
builds over and then east of the region. Temperatures will moderate
towards 70 degrees though (particularly over southern portions of
the forecast area).

The next chance of rain will come Tuesday night into Wednesday as
low pressure, which organizes over the southern plains early in the
week as shortwave energy digs into the area from the Pacific and
northern Rockies, ejects into the Great Lakes and brings widespread
showers with embedded thunderstorms. Precipitation chances will
begin to increase overnight Tuesday night with the widespread
activity then expected  throughout the day Wednesday. Temperatures
will generally be mild as a warm, moist air mass is drawn northeast
into the area within broad southwesterly flow in advance of the
upper trough that is carved out by digging shortwave energy over the
plains and midwest.

A secondary low pressure looks to track into the region in the wake
of this initial midweek low as the upper trough pivots east and
northeast into the vicinity. This will maintain shower chances
on into Thursday (and possibly Friday). Seasonable temperatures with
high in the mid 60s to lower 70s will persist into Thursday before
cooling slightly on Friday within the core of the upper trough.



Slow moving frontal boundary now positioned just southeast of the MI-
OH border will continue to support showers and thunderstorms this
afternoon through tomorrow morning. Leading edge of precipitation
currently moving into Saginaw Bay will continue to weaken in as it
moves across portions of Lake Huron, although a stray lightning
strike still cannot be ruled out. Further south across Lake St.
Clair/western Lake Erie, thunderstorm development remains possible
through sunset with any storms being capable of frequent lightning
and gusty winds. More widespread rain develops after sunset tonight
and lingers through Sunday morning as better upper level support
moves overhead. Otherwise, light N/NW flow prevails north of the
front with SW flow to the south, becoming more uniformly NW by
Sunday. Drier weather expected heading into the early week period
with light winds and waves as high pressure builds in.



Scattered showers and a few thunderstorms will continue to impact
the area late today through tonight and into early Sunday morning
before a cold front shifts east through the area by midday Sunday.
This rainfall should generally be light with around one quarter of
an inch possible in some locations. Hence, there are no flooding


Issued at 153 PM EDT Sat May 21 2022


A cold front pushed just southeast through Detroit this morning with
temperatures in the upper 70s for Detroit and mid 60s over PTK/FNT.
Likewise, winds are more westerly north of the boundary. A second
cold front resides across northern Lower MI and will drop down
through the area tonight bringing drier air with dewpoints in the
30s down for Sunday. But for this afternoon through tonight we`ll
have some opportunities for reduced CIGS/VSBYs due to a moisture
axis up through the area and a low pressure system that will lift
northeast through the area tonight. Lower chances for convection
this afternoon for DTW/DET/YIP as the outflow from this morning
storms helped push instability southward. Still a chance for the
northern periphery of some storms to clip the area so will keep a
short tempo for now. Better chances for rain this afternoon for MBS
as enhanced moisture streams up into central MI. Convection should
wane but a lightning strike or two cannot be ruled out. Best chance
of widespread rain comes tonight as the low lifts along the front
around 04-12Z. Looks like a period of IFR CIGS may occur until
Sunday morning when drier air moves in.

For DTW...Morning convection helped force the better instability to
the south of the area reducing chances for afternoon storms today.
Will be watching for development to the south to nose up into the
area this afternoon but this is lower confidence. More widespread
showers and likely IFR CIGS will move in tonight with a weak low
pressure system followed by improved conditions Sunday.


* Low in ceilings below 5000 feet this afternoon, high tonight.

* Low in ceilings below 200 feet tonight.

* Low in thunderstorms this afternoon and evening.


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



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