Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000
FXUS63 KDTX 200352
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1152 PM EDT Mon Jun 19 2017

.AVIATION...

Periodic pockets of thicker mid level cloud cover will continue to
stream across the region through the overnight period.  Southwest
winds turn gusty as daytime mixing ensues late morning Tuesday.
Thickening high based diurnal cu for the afternoon period, with a
small window for scattered showers/isolated thunder mid-late
afternoon.

For DTW...Modest west to southwest wind through the overnight
period, with limited potential for cigs to fall below 5000 ft during
this time.  Southwest winds turning gusty Tuesday /25 kts/.
Increasing diurnal cu with cigs near 5000ft Tuesday afternoon.  Late
day showers/isolated thunder possible mid afternoon into
early evening.

//DTW THRESHOLD PROBABILITIES...

* Very low for thunderstorms mid afternoon into early evening.

* Low for cigs aob 5000 ft through Tuesday morning. Medium Tuesday
  afternoon.

&&

.PREV DISCUSSION...
Issued at 358 PM EDT Mon Jun 19 2017

DISCUSSION...

Forcing embedded within energetic northwest flow is capitalizing on
several hundred J/KG MLCAPE and a cold pool aloft characterized by -
20C at 18.5kft and is generating widespread garden variety
thunderstorms. Two primary focii of activity exist at press time.
The first is over the eastern half of the Lower Peninsula and is
associated with forcing along the lead edge of the mid-level trough
axis. The second focus of convection is being driven by an embedded
shortwave immiedately behind the longer wave trough axis. Attendant
PV advection will support showers and a few tstorms continuing for
several hours even after the loss of diurnal heating over the Thumb.

As the next wave, presently over far southeast Manitoba, dives
southeast, heights over the western and central Great Lakes will
rise by early Tuesday, forcing the mid-level cold pool north and
east. This will lead to the confinement of any early-day tstorm
activity to locations mainly in the Saginaw Valley and Thumb regions
on Tuesday. Lapse rates over the remainder of SE Michigan will
remain paltry even as a stronger wave pivots through the area on
Tuesday. Strongest forcing for ascent currently modeled to reside
south of I-69 after 21z. While sufficient for high chc to low-end
likely pops, coverage of t-storms Tues aftn is not expected to be as
widespread as today. With little change in airmass, highs will again
top out in the mid to upper 70s, slightly below the average values
for the date.

Pattern becomes briefly more progressive as Aleutian low energy
releases east and forces a short-lived period of ridging to expand
over the central and northern US. 850mb temps in the teens spreading
into the area from the west will allow highs to top 80 degrees at
least Thursday and Friday while the lead edge of deeper moisture
pushing into Great Lakes as aforementioned Aleutian energy tracks
across southern Canada will bring a chance of showers on Thursday.
Cold fropa Friday will mark a return to dominant longwave troughing
and associated transient chc showers/tstorms associated with frontal
passage.

MARINE...
Broad trough of low pressure over the Great Lakes will maintain a
moderate westerly component flow through Wednesday.  High pressure
will bring a lighter easterly flow Wednesday night before
increasing from the south ahead of a cold front that will
pass through the lakes Thursday night.  Scattered showers with the
trough are possible through Tuesday then showers and thunderstorms
possible Thursday along and ahead of the approaching front.

HYDROLOGY...

Showers and thunderstorms will continue through this afternoon until
a cold front sweeps through the area. Plenty of moisture in the
atmosphere supports heavy downpours through this period as has been
the case the last day or so. Radar estimates over Midland and Bay
Counties are around 2 inches from Saturday`s activity training over
that area. Activity should be more progressive today with the front
but those areas that experience thunderstorms could see additional
rainfall totals exceeding an inch. This will result in localized
ponding of water and possible short duration flooding in favorable
drainage basins.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....MR
DISCUSSION...JVC
MARINE.......DRC
HYDROLOGY....DRC


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