Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
1216 am CDT Tuesday Jul 7 2015
Previous discussion... /issued 900 PM CDT Monday Jul 6 2015/
A persistent but relatively small area of showers and
thunderstorms has been moving slowly east northeastward across
portions of northeast Arkansas and is expected to slowly move into the
portions of the Missouri bootheel this evening. The atmosphere is
very moist through this area. The 00z sounding indicated a
precipitable water value of 1.74 inches. Surface dew points are
in the lower and middle 70s. With the slow movement...locally
heavy rainfall and localized flash flooding is possible. Updated
the hazardous weather outlook to mention this threat. Also...have
already updated the zone forecasts and grids to increase the probability of precipitation
through this area...and adjusted the quantitative precipitation forecast grids for this evening. The
hrrr shows this area of convection gradually weakening over the next
few hours...but after midnight additional convection is expected to
develop mainly along and north of Interstate 40.
Discussion... /issued 340 PM CDT Monday Jul 6 2015/
Warm and humid conditions remain across the middle south this
afternoon with only isolated showers developing during the diurnal
maximum of the afternoon. Most locations should remain dry into
this evening as the middle south remains positioned between weather
A shortwave over the Southern Plains will move east across the
middle south later tonight. A strengthening low level jet associated
with this upper level feature will nose into the area and help to
initiate scattered showers and thunderstorms...mainly after
midnight along and north of Interstate 40. This shortwave will
move east Tuesday morning with any lingering convection across
northwest Tennessee coming to an end.
Another shortwave will move by to our north by Tuesday afternoon
as a cold front drops south to the vicinity of our northern County Warning Area
border. Additional showers and thunderstorms should form Tuesday
afternoon and continue into Tuesday night...mainly across
northern areas. As MLCAPES exceed 2000 j/kg and deep layer shear
ranges between 20-30 kts...there may be a stronger storm or two
develop. At this time...it does not appear that widespread severe
weather will occur. There may be an increasing threat for heavy
rainfall as storms tend to move repeatedly over the same areas.
This will need to be monitored for any potential flash flood
The front will begin to lift back northward on Wednesday as
shortwave ridging develops ahead of another shortwave ejecting
northeastward out of the Southern Plains. This should lower probability of precipitation
areawide and confine chances for storms to our far northern areas.
These storm chances should continue into Wednesday night across
our northwest zones as the shortwave clips these areas.
For Thursday into next weekend....upper level ridging builds
strong over the area with a return to more typical middle July Summer
weather. Seasonably hot and mainly dry conditions can be expected
through this portion of the extended forecast period.
The upper ridge will retrograde westward by the end of the weekend
with a return to northwest flow and a series of disturbances
helping to increase storm chances across the northeastern portions
of the middle south.
Aviation...06z taf cycle
VFR conditions should prevail for most of the forecast period.
Some low clouds may move into the ktup area around sunrise Tuesday
morning. Isolated to scattered thunderstorms will track across
west Tennessee...likely impacting mkl before sunrise. Brief IFR
visible due to heavy rain is possible along with gusty wind.
Prevailing winds will be from the south to southwest 5-15
knots...strongest during daytime hours.