Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 032344

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
744 PM EDT Fri Apr 3 2020


Deep column short wavelength ridge will be in place tonight ensuring
quiet weather. Extremely dry airmass is resulting in high static
stability, particularly in the lowest 7.0 kft agl. Ribbon of low to
midlevel equivalent potential temperatures will slowly compress into
the region between 18-00Z Saturday in response to blocking ridge
over Canadian Maritimes breaking down. Plenty of question on
moisture quality-depth of saturation late Saturday afternoon. Best
potential with steepening low level lapse rates appears over MBS and
did include a prevailing group 20-23Z. Lower confidence across
southern sections of CWA.


* None.


Issued at 332 PM EDT Fri Apr 3 2020


Quiet weather marked by sunny skies has held through the morning and
afternoon as an amplified but narrow ridge resides across the Great
Lakes north into Ontario. Broad scale subsidence along with a narrow
ribbon of very dry air (1000-500MB RH around 35 percent) will ensure
the continuation of clear skies this evening and overnight, which
will have observed highs in the upper 50s to lower 60s (colder
across Tri-Cities into northern Thumb due to marine influence)
quickly fall back into the low to mid 30s with efficient radiational
cooling in place. Upstream today, a sheared PV anomaly will carve
across the Midwest and will dampen the aforementioned ridge
throughout Saturday morning and afternoon. Dampening of the ridge
will also coincide with weak frontogenetic forcing, maximized from
the surface up to h850, as a weak cold front travels across SE MI.
Latest guidance has sped up the passage of the front from prior runs
and is adamant on post-frontal dry air filtering in after 00Z
Sunday, thus only real changes to this forecast package is earlier timing
for precipitation. Lack of instability will limit the potential for
thunderstorms. Otherwise, a quicker frontal passage and building
cloud cover will support highs in the low to mid 50s across SE MI.

Quasi-zonal flow will hold to start the week as surface high
pressure builds across the Great Lakes. This will result in the
return of quiet weather marked by mostly sunny skies. Despite the
extended period of sunshine, northwest low-level flow will hold
temperatures to near-normal values. Several chances to see active
weather exists after Sunday as very weak return flow from the
departing high pressure allows a warm front to gradually edge north
near southern Michigan through Tuesday. Baroclinic zones looks to
set up right along the MI/OH border which will have highest odds to
see precipitation, but overrunning could provide enough forcing to
induce precipitation across the cwa. A low pressure ejecting out of
the northern Rockies late Monday is also projected to influence the
Great Lakes late Tuesday into early Wednesday which will be a second
chance for rain and thunderstorms. At this time, little convergence
is noticed between inter and intra model spread, with possible
cyclone locations existing anywhere across MN/WI or as far east as
MI by 00Z Wednesday. Additionally, northern to southern location
variance exists between the GEFS data and latest ECMWF deterministic
run, which will have implications for temperatures (and thunderstorm
potential) for the midweek period. For example, ECMWF MOS advertises
a high in the upper-50s Wednesday relative to the upper-60s in the
GFS MOS (for KDTW). Overall, temperatures to hold near or above
normal to start the week with several chances for rain showers and
thunderstorm activity.


High pressure will remain in place for the rest of today before
eroding east of the area on Saturday. Maritime conditions remain
favorable overnight given a weak surface gradient and stable low-
levels, limiting gust potential. Light winds veer southeasterly early
Saturday morning before an elongated cold front pushes through the
central Great Lakes Saturday afternoon. The front will produce a few
non-convective showers before sunset. Once the front clears east,
winds become northwesterly overnight, in the 10-15 knot range. High
pressure regains control on Sunday to close out the weekend with
mainly dry and calm conditions carrying into Monday.


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



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