Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/22/19

Area Forecast Discussion...UPDATED

National Weather Service Memphis TN

 957 PM CDT Tue May 21 2019

.UPDATE...
Midevening convective analysis showed surface-based CAPE of 1000
to 1500 J/kg east of the MS River, where temperatures prevailed in
the lower 80s and upper 60s, respectively. Midevening AMDAR
soundings at MEM showed a pronounced elevated warm layer around
700mb that was capping deep convection over the low level
instability axis.

Short term convection-allowing models have been consistent in
depicting weakening storms and shallow depth showers slowly
progressing east of MS River during the late overnight, fed by a
45kt low level jet above the boundary layer inversion. 00Z NAM
depicted most if not all the scattered showers and storms
dissipating Wednesday afternoon, as the low level boundary washes
out under a strengthening upper ridge.

PWB

&&

.PREV DISCUSSION... /issued 721 PM CDT Tue May 21 2019/

UPDATE...

Updated to include 00Z aviation discussion below.

PREV DISCUSSION... /issued 322 PM CDT Tue May 21 2019/

DISCUSSION...
A potent shortwave trough is lifting slowly to the northeast
across the Plains this afternoon. A warm front extends eastward
from an occlusion over eastern OK into the lower OH Valley with
the attendant surface cyclone still back over the High Plains.
This warm front took a while to pick up any poleward momentum
today but winds have finally shifted from the south area wide and
the warm front is lifting north into MO/KY. Isolated showers have
occurred throughout the day in the warm sector and are expected
to continue through 00z although coverage will remain very
limited. Temperatures generally range from 85-90F today and will
be among one of the cooler days of the forecast period.

The MCS traversing AR this afternoon will be a player across
portions of the Mid-South this evening into the overnight hours.
The environment is fairly unstable across the Mid-South with
MLCAPE near 1500 J/kg while EBWD ranges from 40-60 kts. While
these parameters are conducive organized convection, by the time
the QLCS to our west reaches northeast AR, instability will be
waning, CINH increasing, and storms will be farther removed from
the strongest forcing aloft. Thus, convection is expected to
weaken fairly quickly. There remains a potential for severe
weather, mainly west of the MS River this evening with damaging
winds being the primary hazard. Otherwise, expect a weakening line
of showers and thunderstorms sagging through the Memphis metro
area sometime around midnight.

The outflow boundary laid down by tonight`s convection is expected
to be a focus for additional showers and thunderstorms on
Wednesday. Instability will be sufficient for occasional strong
updrafts but shear will be weaker, resulting in primarily
ordinary cells or multicell clusters. The severe weather threat
will remain limited during this time. Convection may linger into
the early evening hours, but should dissipate around sunset with
dry weather anticipated overnight.

An anomalously strong subtropical ridge will be the main story by
Thursday with hot and generally dry weather continuing through
the weekend. Ensemble guidance continues to suggest 594-595dam
heights at 500mb which near the maximum observed for the period.
While a few diurnal showers/storms will be possible (mainly in
the northern reaches of the CWA removed from the ridge), most of
the area will remain dry. Temperatures will gradually warm through
the weekend with highs climbing into the lower 90s and afternoon
heat indices eventually reaching the mid 90s. Overnight lows will
be in the upper 60s and lower 70s.

A strong trough will dig over the southwest CONUS by early next
week and is progged to move into the Plains by Tuesday. This will
eventually weaken the subtropical ridge with resulting height
falls implying slightly cooler temperatures and a potential for
precipitation. There are still some differences in the 12z global
models` timing of this trough, with rain chances mostly likely
arrive midweek.

Johnson

&&

.AVIATION...
/00Z TAFs/

A weakening line of showers and thunderstorms will push into JBR
within the hour and eventually into MEM over the next several
hours. Thunder coverage is expected to remain low at MEM, but
carried a VCTS to account for isolated activity. Prevailing TSRA
is greatest at JBR in the short term. The line of showers is
expected to stall near MEM overnight, with activity continuing
through early morning.

MVFR CIGs are possible overnight at JBR and MEM as the front
remains in close proximity. The front will push east tomorrow
afternoon with scattered showers possible at MKL through late
morning. Expect winds to remain southwest 8-12 kts with occasional
gusts to 20 kts tomorrow afternoon.

AC3

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

$$