Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 191052
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
652 AM EDT TUE JUL 19 2016
Pocket of instability residing in the midlevels has been adequate
enough to support isolated showers over southeastern Michigan this
morning. Guidance supports this activity to until approximately 13z
before exiting the state. Models fairly robust with amount of
support for cumulus development today. Trended the tafs to vfr bkn
cigs today. Otherwise, surface high pressure will support quiet
weather with winds responding out of the east by evening hours.
Clear skies are expected tonight.
//DTW Threshold Probabilities...
* Medium for ceilings at or below 5000 ft today.
Issued at 254 AM EDT Tue Jul 19 2016
Quiet weather pattern for the next two days in the wake of the
Monday cold frontal passage. Some moisture around 850 to 750 mbs
will move southeast across the forecast area early this morning
bringing partly sunny skies at daybreak. That should leave by 15z
leaving just scattered cumulus to develop today. 00z guidance temps
for today were in line with on going forecast so not much to change.
Clear skies tonight and dry air with dew points in the 50s will
allow temps to fall into the 50s for most locations. 00z guidance
was quite a bit lower than the ongoing forecast and given the dry
air and ground, will allow the forecast temps to be lower tonight.
Should have a quick warm up in the dry air early on Wednesday before
some modest increase in moisture, warming of most of the column, and
heights start to build. No worries about convection on Wednesday as
the main shortwave will crest the ridge an pass to the southwest of
the state. Would expect any convection that develops Tuesday night
and Wednesday to dive southeast along the 850 mb-300 mb thicknesses
which is lined up nicely with the instability gradient. This
convection will be close enough that some dense cirrus will be a
concern. Without it and with the dry conditions could make a run at
90 for most of the forecast area. For now will stick with mid to
From Wednesday night and really through Sunday, forecast gets
uncertain. Some of the certainties are the increasing heights,
continued warming of the column and increases in moisture. Nose of
the 850 mb jet gets close to the forecast area or just upstream
and Lower Michigan is in the area where shortwaves will be
spilling over the ridge. ML CAPES could be in the 1500-3000+ J/kg,
but there is also some capping potential with the warm temps from
850 mbs to 500 mbs. If convection is timed during the daytime
hours, high temps may only get into the mid 80s. However if there
is no daytime convection, temps will make a run well into the 90s.
Most prudent forecast is to keep pops in the 20 to 45 percent
range and temps within a few degrees of 90 and make adjustments as
each day get closer.
Very quiet marine weather is expected through the middle of the week
both in terms of winds and dry weather. Surface high pressure with
low humidity will be in control of the region both today and
Wednesday. Will see the surface high center build into the open
waters of Lake Huron today causing light and variable wind
conditions offshore with light easterly winds along the shoreline.
Light southerly winds are expected Wednesday. Periodic and
occasional thunderstorm chances will begin by late Wednesday or
Thursday and persist throughout the upcoming weekend. Little detail
or information can be provided at this time on specific
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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