Scientific Forecaster Discussion
fxus64 kmeg 201055
Area forecast discussion
National Weather Service Memphis Tennessee
455 am CST Mon Feb 20 2017
Discussion... /issued 354 am CST Mon Feb 20 2017/
Strengthening southerly flow will prevail over the midsouth
today, in advance of an approaching longwave upper trof over the
Southern Plains. Despite considerable high clouds, high temps more
typical of mid/late April will prevail.
Rain chances will increase considerably west of the MS river this
evening, and over the remainder of the midsouth during the
overnight. North MS will likely receive the most rain on Tuesday,
near the northeast quadrant of a forming closed upper low. This
upper low will remain cut-off Tuesday night, but exit, dropping
into the central Gulf of Mexico by early Wednesday.
Predominately dry conditions will prevail Wednesday and Thursday.
Fast zonal flow aloft will maintain support for southerly low
level onshore flow. Some warm advection drizzle or isolated showers
may occur Thursday near the Tennessee River, under the left exit region
of an upper jet streak.
00z medium range models continued to show a possible rain event on
Friday, but have slightly delayed the timing with a slower and
more neutrally-tilted upper low tracking into the upper MS River
Valley. Best severe threat will likely remain confined to the Ohio
Dry, cooler and less humid conditions to prevail Saturday, before
return flow commences in advance of another upper trof lifting out
of the plains Sunday night. The upper pattern will remain quite
progressive into the first week of March.
12z taf set
VFR conditions will prevail until around 6-7 z when a line of
shras is expected to begin pushing into the mid-south. MVFR
conditions will spread from west to east. Expect conditions to
deteriorate further LIFR and IFR with the heavier showers. Light
winds will increase today to around 10 kts from the southeast.
Kjbr may see speeds over 12 kts as the wind direction switches to
the south during the afternoon hours. Speeds will diminish after
00z. The wind direction may switch around to the northwest at least
briefly behind the line of showers. Also, can't rule out an
isolated thunderstorms and rain developing within the line. However, will leave
mention of thunder out of tafs for now.