Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
FXUS64 KMRX 261849
Area Forecast Discussion
National Weather Service Morristown TN
249 PM EDT TUE JUL 26 2016
.SHORT TERM...(Tonight through Tomorrow)... Ongoing convection this
afternoon will taper off around sunset, and skies will partially
clear overnight. Patchy fog will develop tonight, especially near
rivers and lakes and in areas that see rain this afternoon. For
Wednesday, expect another afternoon of scattered convection as
instability increases with daytime heating. Limited forcing will
minimize the severe threat, with a stationary boundary remaining
stretched across the Ohio Valley and far enough to the north to not
impact our area.
High temperatures will again be slightly above normal on Wednesday,
reaching the lower 90s in the Tennessee Valley, mid to upper 80s
across the Cumberland Plateau, and the mid 70s to lower 80s in the
.LONG TERM...(Wednesday night through Tuesday)...
The closed low pressure system over the MS Delta region today will
continue its northward drift, becoming positioned over West TN
Wednesday night. On Thursday it transitions to an open wave and gets
picked up by a shortwave trough moving into the Ohio Valley. As this
occurs, a steady stream of Gulf moisture will feed into the area,
The NAM is more progressive and a little deeper with the 850-700 mb
trough than the GFS, showing the best rain chances on Thursday. Will
lean the forecast in this direction, increasing pops Thursday and
lowering them slightly on Friday. There will be some potential for
locally heavy rain Wednesday night through Friday as the trough
movement is slow and the deep SW flow may result in training cells.
Increased cloud cover and rain chances will bring temperatures back
to near or slightly below normal both days.
Over the weekend, a broad trough remains over the Ohio and TN Valley
region as a ridge builds over the Plains, but the Atlantic ridge
begins to build back to the west along the Gulf coast. With a
westerly low to midlevel flow, the SW flow of Gulf moisture will be
cut off. This should result in rain chances lowering through the
weekend, with showers becoming more scattered in coverage and
diurnal in timing. Chance pops during the day with slight chance
pops at night will be forecast for Saturday through Tuesday, with
temperatures near to slightly above normal each day.
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 75 91 75 87 / 20 40 60 70
Knoxville McGhee Tyson Airport, TN 73 92 74 86 / 30 30 50 70
Oak Ridge, TN 74 91 74 84 / 30 30 50 70
Tri Cities Airport, TN 71 92 70 86 / 40 40 40 70