739 
FXUS64 KMRX 100730
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
330 AM EDT Wed Oct 10 2018

.SHORT TERM...(Today through Thursday)...For this morning,
a 40kt east southeast 850mb jet will pull abundant tropical
moisture into the southern Appalachians. The associated isentropic
and orographhic lift is producing an area of showers over the 
Carolina. Latest high resolution models show an area of showers,
mainly along north of interstate 40 (especially TRI) this morning
ending by early afternoon.

A break in the showers expected most of the afternoon with
downslope winds into the valley will allow temperatures to warm
under partly sunny sky.

For this evening through Thursday morning, a strong frontal
boundary along with abundant tropical moisture pulling north from
Hurricane Michael will help develop a large area of showers
(possibly a storm this evening south). Also, models show
increasing deformation zone between the 700-500mb layer due to
circulation around Michael and short-wave trough.

For Thursday afternoon, models show drier air spreading quickly
back behind the passage of Michael and upper trough. Clouds and
chances of rain will quickly diminish from west to east.

.Long Term...(Thursday Night through Tuesday)...

Fall temperatures will finally arrive late Thursday into Friday 
morning as Michael races to the northeast across the Mid-Atlantic.
A cold front will sweep across the area on Thursday bringing in 
the first taste of Fall temperatures. Lows Friday and Saturday 
mornings will start out in the 40s across most locations. This 
will be a striking difference with lows recently in the 60s and 
70s. Highs on Friday will only be in the 60s. Highs on Saturday 
will rebound some into the 60s and 70s under mostly sunny skies 
with surface high pressure in place. 

The surface ridge will pass to the east on Sunday as a surface low 
tacks across Texas into the Lower Mississippi River Valley. This 
surface low will be the remnants of Tropical Storm Sergio currently 
over the Pacific. Return flow ahead of the surface low as well as 
synoptic lift from a strong upper jet that will develop across the 
Mid-Mississippi River valley into the Great Lakes region will help 
to saturate the atmosphere. PoPs will increase on Monday as the 
front moves in from the west. With just maybe 12-18 hours of return 
flow ahead of the front, it does not look like temperatures or 
dewpoints will increase enough to yield any surface based 
instability and have just mentioned showers for now with the frontal 
passage. Another shot of cold air will move in behind the boundary 
with lows in the 40s across most areas on Tuesday and Wednesday 
mornings.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             82  70  74  48 /  40  80  50   0 
Knoxville McGhee Tyson Airport, TN  84  69  73  46 /  30  90  80   0 
Oak Ridge, TN                       82  69  74  46 /  30  80  60   0 
Tri Cities Airport, TN              78  68  73  45 /  60  80  90  20 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&

$$