Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 231715

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
115 PM EDT MON MAY 23 2016


High confidence with VFR conditions prevailing through the TAF
period as high pressure remains overhead through tonight. Only issue
for today will be potential for wind shifts this afternoon due to
the lake breeze. The most likely terminals to be impacted by this
will be in the Detroit corridor. (Already arrived at DET per ASOS.)

High pressure will sink southeast tomorrow as a weak area of low
pressure begins to track across the Northern Great Lakes. This will
bring a modest increase in southwest wind and allow for some cu
development late in the TAF period.

FOR DTW...Terminal Doppler radar shows aggregate lake breeze has
released off the lakes and is progressing east towards DTW. Best
idea on timing to reach DTW is between 18-20Z, with current timing
in TAF at 19Z.

//DTW Threshold Probabilities...

* None


Issued at 309 AM EDT Mon May 23 2016


Warm and humid air to build into southeast Michigan for the mid week
period, leading to a good chance of showers and thunderstorms.

For now, dry airmass in place, as 00z dtx sounding indicated a pw
value of 0.24 inches/35 percent of normal. Looking at a slight
increase in moisture amplified upper level ridge axis
moves overhead. The significant change is the low level winds will
shift to the south/southwest this afternoon...albeit light. With full
insolation...expecting highs in the mid to upper 70s as 850 mb
temps rise to 11 to 12 c.

Strengthening low level southwest flow on Tuesday ahead of cold
front will allow temperatures to reach and likely exceed 80
degrees as 850 mb temps reach between 13 to 15 c. An increase in
clouds/convective debris during the afternoon could cause a
disruption to the forecasted highs in the low to mid 80s however.

The moisture plume over the central CONUS extending into south
central Canada will fold over into lower Michigan Tuesday
evening/ upper level jet/wave tracks through Lake
Superior into Ontario. 850 mb dew pts progged to increase to 9 C
as the surface frontal boundary/low level convergence settles over
the area. Modestly unstable airmass (showalter zero to -2 c) will
provide a chance of showers and thunderstorms...but there looks to
be little to no upper level support as flatter upper level ridge
holds. Still, there will be an opportunity for a thunderstorm
complex and subsequent MCV to eject out of the midwest Tuesday
Night-Wednesday...which would support higher pops...especially
during Wednesday as better mid level lapse rates work east and
front begins to return north as a warm front late in the day.
1000-850 mb/mixed layer capes progged to rise to around 1000 j/kg
on wednesday (per GFS)...with 0-6 km bulk shear around 25 knots
suggest limited severe these values are also in line
with the 00z Euro.

Wednesday evening/night appears to be the best shot for rainfall
and thunderstorm 500 mb shortwave trough lifts
through the region and moderate instability (showalter indices of
-2 to -4 C) indicated as 850 mb dew pts push into the 10 to 12 c
range. 700 mb dew pts above zero also indicative of the moist and
deep airmass lifting through as 500 mb low over the northern
plains tracks northeast into Ontario on Thursday...keeping
southeast Michigan in a muddled warm sector with at least moderate
instability building in weakly capped environment.


The week will start out with high pressure sprawled across the Great
Lakes to provide ideal marine conditions. A weak front will then
settle into the straits region Tuesday as high pressure drifts
toward the east. This will result in a general light south wind
turning northeast with an increasing chance of showers and
thunderstorms Tuesday night into Wednesday. Increasingly warm and
humid air will pool along the front as it settles southward
Wednesday night to maintain an active pattern of showers and
thunderstorms over the entire region through the end of the week.
Marine wind will remain light with an easterly component while this
front remains over the region.


A front will settle into the northern Great Lakes Tuesday night and
into southern lower Michigan Wednesday. This will bring an
increasing chance of showers and thunderstorms to the region through
the second half of the week. Warm and humid air will continue to
pool along the front Wednesday night as the boundary takes on more
of warm frontal character. Thunderstorm coverage is expected to
increase during this time and bring potential for significant
rainfall that will likely exceed 1/4 inch and could locally approach
1 inch at times Thursday into Friday.


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



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