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Area forecast discussion
National Weather Service Memphis Tennessee
1133 PM CDT Mon Apr 24 2017


Updated for aviation discussion


Previous discussion... /issued 954 PM CDT Mon Apr 24 2017/


High pressure remains over the mid-south this evening. Clear skies
and light winds have allowed temperatures to already drop into the
upper 50s across much of the area east of the MS river. Expect fog
to begin developing as temperatures drop a little lower. Will
update to add mention of fog. Rest of forecast looks good.


Discussion... /issued 323 PM CDT Mon Apr 24 2017/

Considerable cloud cover has kept temperatures significantly
cooler across northeast Mississippi and near the Tennessee River
in west Tennessee today. Values range from near 60 to the middle

Tomorrow we will begin to see some changes in the weather
pattern. Southerly winds will strengthen across the area bringing
deeper moisture back to the region. Dew points are expected to
surge from the upper 40s to near 60 from Tuesday morning to
Wednesday morning. Skies should remain clear tomorrow as a
shortwave ridge begins to release its grip on the area. Sustained
winds along west of the Mississippi River tomorrow afternoon may
exceed 20 mph with gusts approaching 30 mph. A Wind Advisory may
be needed. Wind speeds should diminish a bit overnight...but
increase to near advisory levels again Wednesday. Another Wind
Advisory may be needed.

A deep trough will dig over the Southern Plains Tuesday and
Tuesday night...showers and thunderstorms...likely a line of them
will move across the midsouth Wednesday night. A deep midlevel
trough will become negatively tilted by midnight helping to
Transfer energy from an 45-55 kt low level jet to the surface. The midsouth
will also be beneath the right entrance region of a 100+ kt upper
level jet helping to maintain vigorous updrafts. We are probably
lucky this system isn't coming through 6-12 hours earlier when
afternoon heating would maximize instability. Nevertheless dew
points in the low to middle 60s should still be sufficient to
enhance thunderstorms. Cape values late Wednesday afternoon are as
high as 2400 j/kg with Li's of -7. By midnight...when storms
should be impacting the region...those values diminish to less
than 1000 cape and -3.5 Li's. Deep-layer shear will be more than
sufficient for supercell thunderstorms and tornadoes. However as
storms conglomerate into a line while approaching the Mississippi
River...tornadoes will become less likely. Straight line winds may
become the largest threat. Large hail also looks likely. The storm
prediction has already included all of the midsouth in a marginal
or slight risk for severe thunderstorms. The slight risk is
primarily along and west of the Mississippi River....marginal
farther east.

We should be between systems Thursday but we will quickly return
to southwest flow Friday and a series of fast moving storm
systems are expected late Friday...Saturday and Sunday. Additional
severe thunderstorms are expected. The storm prediction centers
extended outlooks already include portions of the midsouth in
their 5, 6 an 7 convective outlooks. Stay weather aware this week




Dewpoint depressions are down to 1-3f across eastern sections so
opted to tempo IFR vsbys for fog at kmkl/ktup late tonight otrw
VFR conds will prevail through the period. Light and variable
winds overnight will become southerly and gusty across the Delta
Tuesday morning...diminishing around sunset though likely
remaining above threshold at kmem during the evening.



Meg watches/warnings/advisories...

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