Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 290657
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
257 AM EDT SUN MAY 29 2016
A weak cold front will progress west to east through lower Michigan
late today as a vigorous shortwave lifts from the upper Mississippi
Valley into the northern Great Lakes. A surface trough will precede
this front during the afternoon/early evening hours, providing focus
for scattered convection as moderately unstable conditions develop
within the warm/humid airmass that has overspread the region during
the past few days.
Mid level WSW flow in the 25 to 30 knot range will provide enough
bulk shear to allow for at least minimal convective organization
within the unstable warm sector. Generally expect a few multi-
cellular clusters with overall convective coverage remaining rather
scattered. Timing of the pre-frontal trough actually suggests most
convective initiation will occur over the area during the mid to
late afternoon with this activity then being swept east out of lower
Michigan by 00z or so. During this 4 or 5 hour window, expect a few
storms to at least approach severe limits with isolated large hail
and/or damaging wind gusts. This seems most likely over the Thumb
region where lake breeze convergence will most likely enhance the
updrafts that form along passing trough axis.
Several quiet days will follow as high pressure builds across the
central Great Lakes early in the upcoming week in the wake of this
cold front. While temperatures will still climb into the 80s in most
locations during this time frame, humidity levels will be lower as
the dew point temperatures in the lower/mid 60s of late will be
replaced by readings in the mid/upper 50s. This will also allow for
cooler overnight temperatures in the 50s to around 60.
Warm/humid conditions will briefly build back into the region during
the middle of the week as upper level heights build in advance of
the next shortwave trough as it eject slowly ENE along the US and
Canadian border region. This system will bring an increased chance
of showers and a few thunderstorms from Wednesday into Thursday
before the cold front associated with this upper level trough moves
through the region and brings a cooler/drier weather pattern heading
into next weekend as upper trough becomes established over the
Great Lakes late in this forecast period. Temperatures of 70 to 75
by day and 50 to 55 by night will become common from Friday on into
Areas of fog...potentially dense...will remain possible over Lake
Huron into this afternoon before south winds increasing to 10 to 15
kts ahead of a cold front allows any fog to mix out. The front will
push across the region late this afternoon and evening as low
pressure tracks across Ontario. Showers and thunderstorms will be
possible as the front slides through a warm and humid airmass...with
a few storms becoming strong or possibly even severe during the
afternoon and evening. The biggest threats will be damaging wind
gusts to 50 kts and hail to 1" in diameter. Light westerly flow and
dry weather are expected behind the front for Memorial Day.
Issued at 1152 PM EDT Sat May 28 2016
Persistence of a weakly unstable environment will sustain a low
potential for thunderstorms overnight. With that said, coverage
will remain isolated. In addition, latest model guidance suggests
the ongoing line of thunderstorms entering the Lake Michigan
corridor will diminish considerably prior to reaching the SE
Michigan airspace by mid morning. Otherwise simply lingering
mid/high based cloud cover into the overnight period. Blossoming VFR
diurnal cu field again by midday Sunday. Cold front moving across
the region during the afternoon period will present the greatest
potential for thunderstorm develop during this TAF period.
Introductory mention as a prob30 /20z-24z/ with some uncertainty yet
in possible coverage. Gusty southwest winds briefly emerge for the
afternoon period, with gusts into the 20 knot range.
FOR DTW...Potential for thunderstorms through Sunday morning remains
quite low. The greatest window for thunderstorm development will
occur between 20z-23z Sunday afternoon accompanying a cold frontal
//DTW Threshold Probabilities...
* Low for ceiling at or below 5000 FT Sunday morning...medium
during the afternoon .
* Low for thunderstorms affecting DTW/D21 airspace tonight and
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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