Forecast Discussion

FXUS64 KMEG 242015

Area Forecast Discussion
National Weather Service Memphis TN
315 PM CDT Tue May 24 2022


We have seen a few showers across the Midsouth today but lightning
has been very limited, only recently observed in north
Mississippi. Cloud cover has significantly limited warming today
and thus instability has been limited. Early afternoon
temperatures are in the upper 60s to low 80s. We may see another
degree or so of warming before we reach our afternoon highs.
With weak LAPSE rates, little upper level support and only
moderate instability I do not expect to see rapid strengthening or
development this afternoon. However, tonight, as a 40kt LLJ
develops and a longwave trough shifts closer to the Mississippi
river, showers and thunderstorms should flourish. The Storm
Prediction center has included nearly all of the Midsouth with the
exception of northwest Tennessee in a Marginal threat for severe
thunderstorms in their Day 1 product. Hail and damaging wind
would be our highest threat. Storms will likely continue through
the night.

Tomorrow, the trough will shift even closer to the Midsouth
allowing storms to tap into marginally better dynamic energy.
Thermodynamic support will remain limited. An area of enhanced
area of southwest flow from east Texas across the lower
Mississippi River will help to sustain updrafts. Additionally,
numerous outflow boundaries will likely be in place and a warm
front will lift north across the Midsouth ahead of the approaching
longwave trough and attendant surface cold front. The Storm
Prediction Center has included all of the Midsouth in a marginal
risk for severe thunderstorms in their day 2 outlook. Weak to
locally moderate instability and adequate deep-layer shear along
with the interaction of the numerous surface boundaries mentioned
above should promote numerous multicell clusters of thunderstorms
capable of producing isolated damaging winds and perhaps some
large hail.

Heavy rain will also be an increasing concern over the next 2-3
days. WPC has included most of the Midsouth in a marginal to
slight risk for Excessive rainfall in their Day 1 product. For
Day 2 there is a Moderate risk centered over southwest Tennessee
and a marginal to slight risk for the remainder of the Midsouth.
Flooding is not expected immediately, but by tomorrow afternoon or
tomorrow night a flood watch may be needed. Generally 2.5 to 3.5
inches of rain is expected tonight through early Thursday, but
locally accumulations could be much higher.

Thursday, the longwave trough axis should shift into Middle Tennessee
and Alabama bringing an end to the severe threat across most of
the Midsouth. However a cutoff upper level low will continue to
produce showers and maybe a few sub-severe thunderstorms across
the Midsouth. Showers and thunderstorms should be most numerous
across west Tennessee and north Mississippi Thursday.

Temperatures over the next several days look mild. Afternoon highs
should be in the upper 70s to low 80s Wednesday and in the low to
middle 70s Thursday and Friday. Thursday and Friday morning we
will likely see our coolest temperatures with sunrise temperatures
in the mid 50s to low 60s.

Friday into the weekend looks dry with afternoon high
temperatures back into the upper 70s to mid 80s over the weekend.



.AVIATION.../18z TAFs/

MVFR conditions will continue through most of the period as a
system moves through the Mid-South. Showers and thunderstorms will
move into most sites around this evening, and likely persist
through the overnight period. Winds will also remain elevated,
with LLWS possible this evening. These southerly winds will become
gusty by late night/ early morning and persist through the