Scientific Forecaster Discussion
fxus64 kmeg 181719
Area forecast discussion
National Weather Service Memphis Tennessee
1219 PM CDT sun Aug 18 2019
Update... /issued 1130 am CDT sun Aug 18 2019/
Updated for heat advisory in the west.
Observation trends suggest that heat indices are on track to reach
105 degrees this afternoon along and west of the Mississippi
River...despite the increasing cu field and the threat for an
isolated shower or storm. Heat indices will drop to below criteria
by 8 PM this evening. Therefore a heat advisory has been issued.
Previous discussion... /issued 359 am CDT sun Aug 18 2019/
Currently...weak zonal flow aloft prevails across the region with
surface high pressure stationed over the Atlantic Seaboard. Light
southerly flow is slowly notching up the humidity levels. Temps
range from the upper 60s to mid 70s with clear skies and some
Today through Tuesday night...hot and humid today. Will be
watching the mesoscale convective system over southeast Kansas to see how it evolves. The cams
show a variety of solutions ranging from completely falling apart
to holding together and reaching the Delta late this afternoon.
Will continue 20-30 pops across the western parts of the mid-
south this afternoon. Highs will reach the lower to mid 90s again
and dewpoints will climb a bit. Heat index values will be
knocking on the door of advisory criteria across parts of the
Delta this afternoon. Right now it looks like most areas will
stay below 105f so will hold off on the advisory for now. Any
convection that makes it to the mid-south will die off quickly
this evening with a quiet night expected along with mild temps.
Upper level high pressure building across the Southern Plains will
nose into the mid-south Monday and Tuesday. Hot and humid
conditions will continue with heat index values likely climbing
above 105 degrees across parts of the mid-south...especially the
Delta Region. Heat advisories will probably be needed. Rain
chances will be limited with mainly diurnally driven
afternoon/evening thunderstorms. Nighttime periods will be mostly
rain-free and warm with patchy fog.
Wednesday through Saturday...the upper ridge should continue to be
the main influence on Wednesday with hot and humid conditions
along with possible heat advisories. A mid level trough pushing
through the Great Lakes will send a cold front south toward the
region by the end of the week. GFS/European model (ecmwf) is some disagreement with
how far south the front will move. GFS brings the front into
northern areas by Friday morning while the European model (ecmwf) takes another
day. Either way the combination of the approaching surface front
and weakening upper ridge will translate into increased rain
chances toward the end of the week and slightly cooler
18z taf set
Showers are starting to pop up across the Delta at this time.
Expect the convection to spread northward possibly affecting kmem
after 22z. The convection will eventually diminish around 01-02z.
Meanwhile, around 01-02z, a couple of the cam models are showing
convection, that will develop across Missouri near old outflow
boundaries this afternoon, will move into NE Arkansas. The
convection could be as far east as west Tennessee. At this time,
will continue with thunderstorms in the vicinity wording at kjbr through 06z to account for
this possibility. Thunderstorms in the vicinity may need to be added at kmkl if indeed
convection occurs farther east. Overall, VFR conditions will occur
unless a site is impacted by a thunderstorm. Light and variable
winds will occur through the period.
Arkansas...heat advisory until 8 PM CDT this evening for Clay-Craighead-
MO...heat advisory until 8 PM CDT this evening for Dunklin-Pemiscot.
MS...heat advisory until 8 PM CDT this evening for Coahoma-DeSoto-
Tennessee...heat advisory until 8 PM CDT this evening for Dyer-Lake-