Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Morristown Tennessee
342 PM EDT Monday Mar 17 2014
Short term /tonight and Tuesday/...
drizzle and low clouds continue to linger across the southern
Appalachians and Tennessee Valley this afternoon in the wake of a
cold front that moved through the region on Sunday. The
northeasterly flow in place across the region...combined with the
dense cloud cover has helped to keep temperatures in 40s in most
areas today...and well below seasonable averages. Through some
drier air is slowly beginning to filter into to western and middle
Tennessee...models are indicating that this very moist boundary
layer will persist overnight and into the morning on Tuesday. This
will result in the low clouds likely lingering through the middle to
late morning hours on Tuesday. Low stratus decks of a few hundred
feet or less and some patchy fog are expected to develop across the
region by late this evening and linger through daybreak as well.
Thereafter...the aforementioned drier air and some ridging will
help to erode away this cloud cover and winds begin to veer to the
south. This will allow for some clearing to take place by Tuesday
afternoon and highs to reach the upper 50s to lower 60s in most
Long term /Tuesday night through Monday/...
relatively busy pattern continues...although our area will not be
in the direct path of any major weather systems.
This periods starts Tuesday evening with our area between the system
that is lingering over US now...having moved out to sea over the
Atlantic...and another system in the plains that is headed to the
east-northeast. A weak cold front from this system moves through
Wednesday and a shortwave from this system sweeps through the area
around Thursday morning. Then a larger system with a connection to
the Gulf moves into the region Friday night/Saturday morning...with
a cold front sweeping through and strong high pressure building into
the region by Sunday.
With the front on Saturday there may be enough return flow moisture
to boost the instability for thunderstorms. Will insert slight
chance of thunder for late Friday night and into Saturday for the
southern half of the area.
For temperatures...pretty close to guidance with overall...biggest
exception is the colder air by next Sunday. Also with cold high
pressure building in went below guidance on probability of precipitation toward end of
Preliminary point temps/pops...
Chattanooga Airport, Tennessee 42 62 46 67 / 20 10 10 20
Knoxville McGhee Tyson Airport, Tennessee 39 61 43 64 / 10 10 10 20
Oak Ridge, Tennessee 38 60 43 64 / 10 10 10 30
Tri Cities Airport, Tennessee 33 57 36 59 / 10 10 10 30