Area Forecast Discussion
Issued by NWS Nashville, TN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS64 KOHX 241040

Area Forecast Discussion
National Weather Service Nashville TN
540 AM CDT Mon Apr 24 2017




Well it looks like the upper low just wont let go of precip
chances for the area yet. As the upper low travels to the SE this
morning, by mid day, it will take more of an easterly track,
followed by slightly NE later this afternoon. This may bring yet
another lobe of the upper low over the eastern zones, and provide
enough lift for some afternoon showers on the Plateau. This may
also keep cloud cover around a bit longer today, although model
consensus is to start clearing out from west to east during the
late afternoon. It doesnt look like the clearing will help raise
temperatures as much as previously forecasted, so dropped high
temperatures this afternoon a bit to have most of the area see the
mid to upper 60s. Should skies break up a bit earlier, afternoon
sun should raise temps a bit more into the low 70s, but for now
thinking cloud cover will hold and keep the area in the 60s.

Some cloud cover may stick around Monday night into Tuesday
morning, but partly cloudy skies may not be enough to prevent fog
development across the area. Light winds and abundant surface
moisture from the weekend rain should allow for fog overnight into
Tuesday morning. Tuesday and most of the day Wednesday look to be
dry with shortwave ridging overhead, and southwest flow aloft will
be in place later on Tuesday thanks to the approaching Plains
trough. Models continue to slow the progression of this wave so it
looks like daytime Wednesday will remain dry as the trough
approaches. Some precip may make it across the TN River Valley
Wednesday evening, but it appears more likely that showers and
thunderstorms will move across the river after midnight. Chances
will continue during the day Thursday as the cold front moves
through, and precip chances should exit the area Thursday evening.

The GFS and ECMWF still differ on Friday`s solution, with the
ECMWF being wet and the GFS being dry. Kept chance pops in for now
during the day Friday since the ECMWF is quite aggressive with
shortwave activity in southwest flow aloft. Saturday has now begun
to look drier as the next Plains trough digs southward into TX,
giving the region some ridging effects. Took out precip chances
Saturday and Saturday night, but chances return Sunday as the
trough and associated cold front begin to impact the region. Model
timing is not lined up just yet, so pretty much have chance pops
for now until models agree on a solution. Both the GFS and ECMWF
do have the cold front moving through Sunday night into Monday
morning with a squall line signature, however instability is weak
due to lack of diurnal help when fropa occurs. Still plenty of
shear, however, so some strong to severe storms may be possible
Sunday night into the early part of the day Monday, depending on
when the front moves through.

Models do place quite a bit of instability over the region Friday
thanks to the southwest flow aloft and plenty of WAA/moisture
advection. However, with the lack of a stronger shortwave, the
GFS is not kicking off much convection over the mid state. The
ECMWF, as mentioned earlier, does have some shortwave activity
with decent instability and shear, so if ingredients line up a bit
better, some strong to severe storms may be possible on Friday
afternoon/evening as well as Sunday night. Not too concerned just
yet as model agreement is weak, and will need more consistent
solutions between the models to increase confidence in severe
potential Friday and Sunday.



MVFR/IFR cigs to continue today as upper low slowly shifts east
away from our area. Uncertain on if/when low cigs will break this
afternoon but have leaned towards GFS LAMP model on return of VFR
conditions. Fog likely late in the TAF period at all airports with
MVFR/IFR vis or lower. North to northeast winds 5 to 10 knots
today will become light and variable Monday night.





AVIATION........Shamburger is the U.S. government's official web portal to all federal, state and local government web resources and services.