Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
FXUS64 KMRX 270724
Area Forecast Discussion
National Weather Service Morristown TN
324 AM EDT SAT AUG 27 2016
.SHORT TERM (Today and Tonight)...
Current water vapor imagery and RAP upper air analysis indicate a
594 dm high located just to northeast of the area. A weak shortwave
trough in the upper level flow moving around the periphery off the
ridge has lead to a few showers and storms continuing at this
early hour across Western Kentucky. There were a few showers
lingering across southern portions of the forecast area late
tonight but those showers have now come to an end. At the surface,
an E-W oriented boundary stretches across the Central Plains
extending eastward into the Mid-Atlantic. Closer to home, low level
winds are weak with dewpoints currently in the upper 60s to mid
70s. With these conditions, expect a few areas of patchy fog this
morning but not expecting anything as bas as yesterday morning.
For today, models indicate that a weak 300mb jet streak will move
across the region around the periphery of the upper level ridge.
Wind speeds in this jet streak are only forecast to be around 35-
45kts but it will provide some weak lift. At the low and mid-levels,
winds will be from the SE around the high located to the NE. These
downsloping winds will hinder any vertical motion. PW values will
range from 1.3-1.8 inches with the lower values across SW VA and
higher values in SE TN. The higher values are near the 90th
percentile for late August. Overall, expect isolated to scattered
afternoon showers and storms with best chances across the higher
elevations. Temperatures in the valley will top out in the mid 90s
with the downsloping winds with max heat indices around 100.
.LONG TERM (Sunday through Friday)...
Little change in the overall weather pattern early in the
period...so made little change in the overall forecast. High
pressure will stay in control through much of the extended. As a
result...will see continued above normal temperatures with highs
across the valley generally ranging from the upper 80s to low 90s.
The strong daytime heating will provide diurnal convection most
afternoons with best chance over higher elevations. An occasional
weak disturbance tracking through the region will aid convective
development. There continues to be a lack on consistency late in
the period but generally do not see a significant change in the
weather pattern and will keep isolated to low chance pops in place
for Thursday and Friday.
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 95 73 92 72 / 30 10 30 20
Knoxville McGhee Tyson Airport, TN 95 72 90 69 / 20 10 30 20
Oak Ridge, TN 95 72 90 69 / 20 10 30 20
Tri Cities Airport, TN 93 69 89 67 / 20 10 30 20