Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Morristown Tennessee
305 am EDT Friday Jul 11 2014
Short term (today and tonight)...
surface high pressure to the north will provide a low level NE
flow...with a dry northwest flow through the middle and upper levels. Forecast
soundings in the Tennessee Valley look pretty stable today...so most of the
area should stay dry. Some convective development may occur this
afternoon in the higher terrain of SW NC and the smokies...as
depicted by the rap and hrrr. Will include a slight chance pop in
those areas. Anything that develops should dissipate by 00z. Will
have temperatures today a little higher than yesterday...but below
GFS MOS guidance which seems too warm.
Long term (saturday through thursday)...
a Flat Ridge of high pressure will be over the Tennessee Valley
for Saturday and Sunday with a gradual increase in
moisture/instability. Only forcing for convection with be
orographic..so will have probability of precipitation mainly over the higher elevations.
For Monday and Tuesday...an unusually strong upper low will drop
across the Great Lakes region. Strong upper troughing will be over
the Tennessee Valley/southern Appalachians with a cold front passage
for late Monday night/Tuesday. Increasing instability ahead of the
boundary will increase the coverage of storms for Monday/Monday
night and Tuesday. Due to the strength of the front for July and
decent instability...I am concerned for strong to severe storms for
Monday afternoon/evening. Main concern will be damaging winds.
Will call for high chance/likely probability of precipitation for Monday afternoon through
Tuesday. As timing of frontal passage and potential of pre-frontal trough
becomes more clear...categorical probability of precipitation will likely be needed.
An unseasonably cool airmass spills into the area for Wednesday and
Thursday with mainly dry conditions. Generally went a degree or two
cooler than GFS mex highs through the period.
Preliminary point temps/pops...
Chattanooga Airport, Tennessee 90 69 93 70 / 10 10 10 10
Knoxville McGhee Tyson Airport, Tennessee 88 67 91 69 / 10 10 10 10
Oak Ridge, Tennessee 88 66 91 68 / 10 10 10 10
Tri Cities Airport, Tennessee 88 63 88 64 / 10 10 10 10