Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
1249 am CDT Thursday Sep 18 2014
Updated for the 06z aviation discussion.
Previous discussion... /issued 948 PM CDT Wednesday Sep 17 2014/
Decreased probability of precipitation overnight due to current conditions. Still
confident in the hrrr solution of showers in the morning.
Increased cloud cover throughout the day tomorrow to reflect the
increased moisture associated with the disturbance approaching the
Previous discussion... /issued 321 PM CDT Wednesday Sep 17 2014/
Northwest flow aloft will prevail over the midsouth through early
Friday. In the short term... an mesoscale convective system over northern Arkansas will drift southeast
this evening. Upstream rear propagation tendencies this evening
may result in additional showers and thunderstorms eventually
moving into eastern Arkansas and perhaps west Tennessee and northwest MS
Short term models vary a bit with upstream convective initiation
early on Thursday. GOES water vapor imagery showed a weak shortwave
moving into the western nebr Panhandle that could help enhance
convection over the Ozark Plateau and perhaps portions of the
midsouth on Thursday.
By Friday... an upper level height ridge will move into the lower
MS River Valley from the Southern Plains. Residual moisture from
Tropical Depression Odile will override the top of the ridge...
eventually consolidating into the base of a northern branch
longwave trough dropping into to the Ohio Valley. This moisture will
make a brief appearance in the midsouth on Sunday... followed by
dry northwest flow aloft. 12z European model (ecmwf) and GFS were in good agreement
for the Sunday through Tuesday periods.
Upper heights will build again toward the middle part of next
week...as the eastern Continental U.S. Longwave trough lifts out to Canadian
Maritimes. A weak slow moving trough over the Southern Plains will
keep rain chances well to the west...while drier low levels and
upper ridging limit midweek rain chances for the midsouth.
06z taf set
Models indicating redevelopment of rain showers/thunderstorms and rain showers across SW MO
overnight. Thus far one cell has developed but if more does develop
the activity could push into kjbr around 7-8z...possibly getting to
kmem around 9-10z. Will continue mention of thunderstorms in the vicinity wording. Ceilings will
gradually lower to MVFR tonight. Some patchy fog could develop at
kmkl as well. Should return to VFR during the morning hours.
Generally light and variable winds expected through the period.