Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
FXUS64 KMRX 240825
Area Forecast Discussion
National Weather Service Morristown TN
325 AM EST Tue Jan 24 2017
.SHORT TERM /Today and Tonight/...
Low pressure system has exited the Southern Appalachians, but wrap
around moisture and a consistent 5-10 mph NW flow has kept low
stratus and some light sprinkles across most of the area overnight.
This activity will begin to wane around daybreak as drier air works
its way into the Tennessee Valley. Given the progged moisture in
the Boundary Layer and the inversion in place, think that clouds
will stick around for most of the moisture. However, by midday into
the afternoon, these clouds will quickly dissipate, resulting in
mostly sunny conditions by the afternoon. Highs will warm into the
low to upper 50s as winds back to the WSW later in the day and
heating is allowed to occur. A dry, and cooler night will then
occur due to the clear and calm conditions as lows drop well into
the 30s in most locations.
.LONG TERM /Wednesday through Monday/...
At the beginning of this
period a progressive pattern is on the move, with a shortwave upper
ridge overhead, but a trough out in the Plains is quickly
approaching. At the surface, the ridge has moved to the east and a
return flow is underway with S-SW low level winds across the area. A
cold front ahead of the upper trough is approaching the Miss River.
The front should sweep through our area around Wednesday evening,
with just showers as the richer instability stays to the south. From
Wednesday night through the weekend, a very unsettled pattern
dominates, with clipper after clipper sweeping across the region.
Lift and deeper moisture are questionable in how plentiful each will
be and how far south each will extend from the main sources to the
north. Finally, around next Monday at the end of this forecast, the
models agree that the pattern will relax somewhat with clippers
passing farther north, and finally by the time the surface ridge
will be settling into the area with very cold air.
For changes to the initialized grids, went generally cooler than
guidance on Max Temps Friday through Monday by 2-3 degrees and
bumped up sky cover during that time period. The only Min Temp that
was adjusted was the last grid, next Monday night, when the surface
high will be overhead, think temps will plummet, so took Mins 3-4
degrees below guidance. Keeping only guidance POPs during the
weekend, GFS is very aggressive with lift/moisture, but might be
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 58 42 64 39 / 10 0 30 30
Knoxville McGhee Tyson Airport, TN 56 41 64 38 / 10 0 20 40
Oak Ridge, TN 56 41 61 38 / 10 0 30 40
Tri Cities Airport, TN 51 35 63 38 / 20 10 20 50
NC...Wind Advisory until 11 AM EST this morning for Cherokee-Clay.
TN...Wind Advisory until 11 AM EST this morning for Blount Smoky
Mountains-Cocke Smoky Mountains-East Polk-Johnson-Sevier
Smoky Mountains-Southeast Carter-Southeast Greene-Southeast