Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Memphis Tennessee
341 PM CDT Friday Aug 29 2014

Discussion...water vapor satellite/upper air profilers/WSR-88D
VAD wind profiles places a longwave trough extending from the
northern plains/upper Midwest and stretching south into the
central/Southern Plains this afternoon. A subtle lead shortwave
trough located across the lower Mississippi Valley is resulting in
isolated to scattered showers and thunderstorms across the middle
south late this afternoon...especially along and west of the
Mississippi River. Temperatures as of 3 PM CDT are predominantly
in the 90s where rain hasn/T occurred yet and lower to middle 80s
near Memphis and Blytheville where isolated convective activity
has already occurred. Precipitation chances throughout the
forecast is the primary forecast challenge in this afternoon/S
forecast.

Short term...(tonight through sunday)...showers and thunderstorms
associated with a lead shortwave trough moving across the lower
Mississippi Valley will support at least isolated/scattered rain
chances especially along and west of the Mississippi River this
evening. This activity is anticipated to diminish in coverage with
the loss of daytime heating by this evening. Additional showers
and thunderstorms may develop later tonight into the overnight
hours as the upper level trough moves into the lower Mississippi
Valley and weakens. Shower/thunderstorm chances seem decent for
Saturday and Saturday night. Thus...have kept likely probability of precipitation going
for this timeframe from this morning/S forecast. Precipitable
water values are anticipated to be above 2 inches which would
support a potential for heavy rainfall. However...given the recent
very dry conditions across the middle south will not issue a Flash
Flood Watch at this time and instead mention localized heavy
rainfall potential in the hazardous outlook. Highs this weekend
will be slightly cooler in the 80s due to convective activity with
lows in the 70s.

Long term...(monday through friday)...latest 12z GFS/European model (ecmwf) long
term models indicate the upper level ridge will gradually build
back in across the lower Mississippi Valley through the week.
Unfortunately...the long term models still have some
discontinuity for middle week as the GFS keeps the upper level ridge
in place and the European model (ecmwf) hints at a weakening ridge. Have trended
the long term forecast towards the GFS solution...and think any
convective activity will be mainly diurnally driven during the
afternoon and early evening hours each day. Afternoon highs will
be in the lower to middle 90s with lows in the 70s.

Cjc
&&

Aviation...
18z tafs

VFR to prevail areawide through early evening. Rain showers/thunderstorms and rain chances
will increase after 03z...slowly edging east with the approach
of the upper trough from the Southern Plains. 18z tafs were based
primarily on the 12z NAM model...with best thunderstorms and rain chances associated
with an approaching warm front after 06z.

Pwb



&&

Meg watches/warnings/advisories...
Arkansas...none.
MO...none.
MS...none.
Tennessee...none.
&&

$$

National Weather Service Glossary of Abbreviations