775 
FXUS64 KMEG 201741
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1241 PM CDT Mon Apr 20 2020

.UPDATE...

See the 18Z aviation discussion below. 

&&

.PREV DISCUSSION... /issued 605 AM CDT Mon Apr 20 2020/ 

DISCUSSION... /issued 434 AM CDT Mon Apr 20 2020/ 

Early morning GOES water vapor imagery showed an upper low moving
into northwest GA. Behind this feature strong midlevel subsidence
prevailed over most of the Midsouth, clearing skies and creating 
prime conditions for radiation fog. A Dense Fog Advisory may be 
needed before daytime heating mixes the lower atmosphere later 
later this morning.

Northwest flow aloft will prevail through Tuesday night, around
the southern periphery of a deep longwave trof centered over
eastern Ontario. The models have been consistent over the last
several runs in depicting a weak shortwave dropping southeast
across the mid-MS River valley and Ozarks this evening. Steep
midlevel lapse rates will accompany weak elevated instability (at
or below 500 J/KG) over northeast AR this evening, suggestive of a
potential for small hail. 

Medium range models remain in good agreement with a southern
branch trof lifting out of the plains Wednesday afternoon.
Compared to yesterday's model output, today's consensus depicts a
more positively-tilted orientation, slightly weaker/more open.
Given the limited return flow period and time of day passage
through the Midsouth, instability will likely be limited to a 
range of 500 - 1000 J/KG. Worth noting, despite the more open 
depiction of the 500mb trof, a surface low of 998mb - 1002 mb is 
progged by the models to track north of and parallel to I-40 
Wednesday night. Regardless of Wednesday night's severe
thunderstorm potential, it'll likely be windy in places.

A follow-on rain event to Thursday will occur as early Friday
afternoon, as open trof embedded in northwest flow drops into the
MS River valley. Sufficient instability may arrive via 40 knot low
level jet extending from the Sabine River valley into the Midsouth.

PWB

&&

.AVIATION...
18Z TAF Set

VFR conds through the period. Light westerly winds this afternoon
under clear skies. A cold front will push through all sites 
tonight through tomorrow morning, but only clouds and low rain
coverage is expected. Carried only a VCSH at MEM and MKL...with 
VCTS possible at JBR. 

Winds will shift to the northwest behind the front by tomorrow
morning. 

AC3

&&

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

$$