Forecast Discussion

FXUS64 KMEG 171113

Area Forecast Discussion
National Weather Service Memphis TN
613 AM CDT Mon Jun 17 2019


Updated to include 12z aviation discussion.


.PREV DISCUSSION... /issued 353 AM CDT Mon Jun 17 2019/

The upper-level cyclone over the Southern Plains will continue to
track to the east today, crossing the Mid-South this evening. A
cluster of thunderstorms developed in the warm advection regime
downstream of this trough during the evening hours with additional
development expected to our west early this morning. Scattered
convection will develop this morning across the Mid-South,
continuing through the afternoon and evening hours. Instability
doesn`t look quite as impressive as Sunday, but will still be
sufficient to support strong updrafts. Coupled with 0-6km bulk
wind difference around 25 kts and there is a potential for a few
organized multicells this afternoon. Like yesterday, the primary
concern will be damaging wind given the mid-level dry air, steep
low-level lapse rates, and precipitable water near 1.75".

Storm coverage and intensity are expected to diminish bu mid
evening, but we`ll maintain a potential for a few showers and
thunderstorms through the overnight hours. Additional convection
is expected on Tuesday, with the greatest coverage east of the MS
River. We do anticipate a bit of a lull in precipitation chances
Tuesday night into early Wednesday, but rain chances will increase
quickly Wednesday afternoon into the overnight period as the next
trough approaches from the west. Instability will increase
Wednesday afternoon ahead of the trough and deep-layer shear will
be sufficient to support organized convection. Storm coverage is
expected to be scattered, but some strong to severe storms will
be possible. In addition, rainfall amounts of 1-2" will be

This midweek trough is expected to be a more progressive, open
wave, limiting the highest rain chances to Wednesday night and
early Thursday. Rain chances will decrease from west to east on
Thursday afternoon as the trough moves east and shortwave ridging
builds over the region.

The subtropical ridge begins to build over the Southeast on
Friday, nosing poleward into the Great Lakes this weekend.
During this time, a deep trough will dig over the western CONUS,
eventually lifting northeast across the Northern Plains this
weekend. While this ridge will normally spell the end of organized
precipitation, the Mid-South will be on the northwest periphery
of this ridge and any shortwave troughs moving through the flow
aloft may still have an effect. Moisture/instability will be in
place through the weekend, to go along with seasonally warm
temperatures. This may induce diurnal convection, although
subsidence aloft should begin to develop a cap. That said, 20-30%
PoPs are warranted through the weekend given the uncertainty and

Temperatures will generally be in the low/mid 80s through
Thursday, but will return to near 90F by the weekend. Heat
indices are forecast to approach 100F Friday/Saturday. Expect
seasonal overnight lows in the upper 60s to mid 70s.



12z TAFs

VFR conditions will continue through the afternoon hours. A
shortwave trof aloft will create showers and thunderstorms, with
the best chances being this afternoon and evening. Winds will
remain southerly and under 10 knots this afternoon, becoming
lighter after sunset. TSRA should become SHRA by late in the
period as upper trof moves over the region. This could also create
some low clouds, but not enough confidence to include at this