Scientific Forecaster Discussion
fxus64 kmeg 260536
Area forecast discussion
National Weather Service Memphis Tennessee
1136 PM CST Sat Feb 25 2017
Updated for the 06z aviation discussion.
Previous discussion... /issued 817 PM CST Sat Feb 25 2017/
updated to lower temperatures.
Portions of northwest Tennessee and north Mississippi cooler faster than
forecast this evening. Adjusted current temperatures...along with
lowering a few overnight lows accordingly. All other forecast
parameters are currently on track.
Previous discussion... /issued 333 PM CST Sat Feb 25 2017/
At 230 PM, a clear cool late winter day taking place across the
mid-south this afternoon with temperatures in the 40s. For
tonight, a 1025mb surface high pressure will become centered over
the middle Tennessee. Temperatures are expected to fall into the
low to upper 20s areawide under clear skies and nearly calm winds.
This will be the first hard freeze for most of the forecast area
in over a week. The coolest readings will drop into the lower 20s,
especially along the Tennessee River valley.
As the surface anticyclone shifts east on Sunday, surface winds
will quickly turn around to the south and push temperatures back
into the upper 50s during the day. With low relative humidity
values and winds increasing to around 10 knots, an elevated fire
danger will exist across portions of northeast Mississippi and
west Tennessee. Cloud cover is expected to increase by late
afternoon ahead of an approaching shortwave trof.
By Sunday night, a dry airmass will quickly turn over and rain
chances will ramp up quickly around midnight. Isolated thunder
will be possible as a weak shortwave lifts across the area. By
Monday morning, a warm front near the arklamiss is progged to lift
northward across the mid-south throughout the day. Rain chances
will remain high near the front with scattered thunderstorms
possible during the day.
A broad surface low in the Central Plains is expected to deepen
and traverse to the Great Lakes region on Tuesday afternoon.
Instability will increase substantially during the day as
temperatures rise into the upper 70s and dewpoints climb into the
low to mid 60s. Scattered thunderstorms will be possible much of
the day. By Tuesday night, the main trof will begin to eject from
The Rockies. This wave will begin to overspread eastern Arkansas
late Tuesday night, with the trof acquiring a positive tilt as it
moves into the lower Mississippi Valley through Wednesday
All the usual suspects for a severe weather event will be in
play during this period including: nicely curved hodographs, bulk
shear values near 60 knots, SBCAPE in excess of 1000 j/kg, and
steep low and mid level lapse rates. Right now, the Storm
Prediction Center has put the eastern part of the mid-south in a
slight risk on Tuesday with the western half outlooked for
Wednesday as well. It's a little too early to sort out exact
details, but all guidance is aligned with at least the potential
for a few severe thunderstorms. Will continue to mention severe
thunderstorms in the hazardous weather outlook for Tuesday night
The cold front will push through by late Wednesday, bringing an
end to showers and thunderstorms. A cool night is expected with
lows bottoming out in the 30s by Thursday morning. Benign weather
is expected for Thursday into next weekend. Temperatures will
hover near seasonal values with highs near 60 and lows in the 40s.
VFR conditions will prevail through the period. Light and variable
winds overnight will become southeasterly between 8-11 kts on
Sunday before gradually diminishing Sunday evening. Clouds will
increase later Sunday and lower Sunday evening...approaching MVFR
cigs just beyond the forecast period.