Area Forecast Discussion
Issued by NWS Memphis, TN
FXUS64 KMEG 270001
Area Forecast Discussion
National Weather Service Memphis TN
701 PM CDT THU MAY 26 2016
Update to increase pops this evening across areas along and north
if Interstate 40 this evening.
A mesoscale convective system (MCS) continues to advance southward
across west Tennessee this evening with strong wind gusts and
small hail...with winds occasionally reaching severe limits as it
progresses into an unstable airmass represented by mlcapes on the
order of 2000 j/kg. Further west across northeast Arkansas and the
Missouri Bootheel...numerous less organized convection with pulse
severe at times with mainly near severe wind gusts and heavy
rainfall will continue this evening. All convective coverage and
intensity will wane later this evening.
Another shortwave will approach from the Arklatex after midnight
with increasing chances for showers and storms mainly along and
west of the Mississippi River.
Updates to increase pops this evening have been sent.
.PREV DISCUSSION... /issued 310 PM CDT THU MAY 26 2016/
DISCUSSION...Water Vapor satellite/WSR-88D Vad Wind Profile
trends this afternoon indicate the development of a Mesoscale
Convective System across southeast Missouri along last nights
convective activity across southwest/east central Missouri.
Another MCS is located across eastern Texas. At the surface, a
warm front is located over portions of the central Plains and into
western Missouri with a cold front over the Texas/Oklahoma
panhandle and a dryline extending south into west Texas. Further
east, a ridge of high pressure is centered over the southeast
United States. Deep low level moisture is being advected up into
the lower Mississippi Valley in between these two features with
surface dewpoints in the lower 70s. As of 2 pm CDT, temperatures
across the Mid-South are in the 80s to around 90 degrees.
Strong/Severe thunderstorm potential remains the predominant
challenge in this afternoon`s forecast issuance.
Short term model/convective trends suggest shower and thunderstorm
coverage should increase across the forecast area into this
evening as a convective outflow boundary from activity over
western Kentucky moves south. At this time, think the best
coverage will occur north of I-40 and along and west of the
Mississippi River. Surface based CAPE values approaching 3000
J/kg, steep 700-500 mb layer mid-level lapse rates, and overall
weak shear suggest pulse type thunderstorms with perhaps some
quasi-organization. Damaging winds will be the primary severe
thunderstorm threat with perhaps a secondary threat of large hail.
Localized flash flooding from heavy rainfall is also possible.
Models indicate additional shortwaves embedded within southwest
flow aloft will move across the Lower Mississippi Valley into the
weekend. This is expected to result in the development of
additional isolated/scattered showers and thunderstorms with the
best coverage over north/northeast Arkansas and the Missouri
Bootheel with overall coverage diminishing somewhat towards the
end of the weekend. Long term models indicate showers and
thunderstorm chances will continue into next week as an upper
level ridge will remain over the southeast United States and
another front approaches from the Middle Mississippi Valley and
00z TAF Set
Reductions in cigs/vsbys will continue in convection this evening
at all sites except KTUP. Strong wind gusts will also be likely
with the strongest storms. Convection should diminish in coverage
and intensity later this evening with a return to VFR conditions.
Late tonight another shortwave will approach and bring additional
chances for convection...especially to KJBR and maybe as far east
as KMEM. In addition...lowering mvfr cigs are expected as stratus
redevelops before sunrise.
MVFR cigs should mix out by mid morning with a return to VFR
conditions. There will likely be additional thunderstorms again by
Friday afternoon during peak heating.