Scientific Forecaster Discussion
fxus64 kmrx 231930
Area forecast discussion
National Weather Service Morristown Tennessee
330 PM EDT Fri Jun 23 2017
Short term (this afternoon through saturday)...
the circulation around the remnants of Cindy is producing very
favorable hodographs/shear for rotating updrafts. Main limitation
is instability. Mixing has lowered dewpoints some across the
region into the middle 60s to near 70, which is still quite high.
As mid-level dry slot continues to move into the region this
afternoon instability will increase with MLCAPE increasing to
400-800 j/kg. Low Cape and high shear environment will be
conducive to the potential of low topped supercells.
Latest meso-analysis data shows 0-1km shear of 30-35 and 0-6km
shear of 40-50, so very high shear values stp values of 4-5 near
Huntsville with 1-2 across the plateau and southeast Tennessee.
Besides the shear, strong low-level jet of 50-60kts later today
will increase the potential of damaging winds due to Bow radar
Tornado Watch has been issued for the western half of the area
Circulation/low pressure will move east of the area late this
evening/early morning. Next feature of interest will be frontal
boundary that is moving across the Ohio Valley. This boundary will
move across the area Saturday. Airmass along and ahead of the
front will be unstable, so expected scattered/broken showers and
thunderstorms, mainly during the morning Saturday.
Dry air will pull into the region for Saturday afternoon with a
return of sunshine.
Long term...(saturday night through thursday)...
front will be south east of our area along with the precipitation
and moisture from Cindy as well. A surface high pressure and mid
level zonal/weak trough will then set up over our area. The drier
air out of the northwest will help keep the skies mostly sunny the
end of the weekend and into work week. Temperatures will remain
below normal and winds will be light during this time frame. The
next round of weather will hold off until the end of the work week
into next weekend. The surface high will eventually move off the
East Coast and increased moisture will be allowed in from the Gulf
of Mexico. Warmer temperatures will also be brought in and the
combination of warm temperatures and increased moisture will lead
to shower and thunderstorm activity over next weekend. This is
still far enough away that the details are a bit fuzzy at this
time for this next event.
Preliminary point temps/pops...
Chattanooga Airport, Tennessee 72 85 64 84 / 80 60 10 0
Knoxville McGhee Tyson Airport, Tennessee 70 82 62 81 / 90 50 0 0
Oak Ridge, Tennessee 71 84 62 82 / 90 40 0 0
Tri Cities Airport, Tennessee 68 82 59 79 / 80 50 0 10
Tennessee...Wind Advisory until 1 am EDT Saturday for Blount Smoky Mountains-
Cocke Smoky Mountains-Sevier Smoky Mountains.