Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
600 am CDT Monday Apr 27 2015
Discussion... /issued 415 am CDT Monday Apr 27 2015/
GOES infrared/WV imagery showed a closed upper low centered near the
Texas/nm border. A linear mesoscale convective system extended from East Texas into the Texas
coastal plain...propagating east/southeast. Klzk radar showed and
east/west band of light showers over southern Arkansas... into west
central MS. Extensive middle and high clouds from the Texas mesoscale convective system were
flowing into the lower MS valley.
Today should see considerable high cloudiness continue over the
midsouth. A few showers may move into the east central Arkansas/northwest
MS Delta this morning...aided by a weak mesoscale convective vortex ejecting eastward out
of the arklatex. Once this feature passes or gets lost under the
upper level shortwave ridge...rain chances near and the southwest
of Memphis should wane toward midday. Given the extensive high
clouds and weak low level cold advection...have undercut model
ensemble MOS temperatures by a degree or two for maximum temperatures today.
Rain chances will increase by late tonight...once the shortwave
ridge passes to the east and increasingly diffluent upper level
spreads into the midsouth. Given the relatively slow movement of
the closed low...rain chances will persist into early Wednesday
morning west of the MS river...and into Wednesday afternoon near
the Tennessee River. Precipitable water values will not be particularly
high north of i40 through the event...mainly under 1 inch...while
up to 1.5 inch precipitable water values are likely Tuesday afternoon over
GFS and European model (ecmwf) are in good agreement in dropping a northern branch
upper low directly south from the Great Lakes on Thursday...
behind the exiting southern branch low. Scattered showers will
likely occur over the Tennessee River valley before the northern branch upper
low departs Thursday evening.
Upper level ridging should bring dry weather and warming temperatures
across the midsouth for the weekend.
12z taf set
VFR conditions expected over the next 24 hours. NE winds will
increase to 10-13 kts with higher gusts this morning. Gusts may
drop off after 00z but expect sustained speeds to remain the same
into the overnight hours.