Area Forecast Discussion
Issued by NWS Nashville, TN
FXUS64 KOHX 172315
Area Forecast Discussion
National Weather Service Nashville TN
515 PM CST Tue Jan 17 2017
FOR 00Z AVIATION DISCUSSION.
Rain has moved off to the east with the cold front, which is
slowly working its way out of the area. Models want to keep rain
chances mainly along the Plateau this evening and even into the
early overnight hours as the cold front tries to hang on with the
upper low. As the upper low slides to the southeast from the Great
Lakes, shortwave ridging will move in over the area which will
keep the area mostly dry on Wednesday. However, late Wednesday
into the morning on Thursday, the next strong upper closed low
will begin impacting the area.
Models are in good agreement with the next low, so kept pops on
track with chances moving in from the west 00Z Thursday. By 12Z-
18Z Thursday, the upper low should be over the Plains, and subtle
shortwave activity over the MS River Valley should help precip
spread over the entire mid state, with better chances west of
I-65. During the afternoon, models bring instability up a bit
although shear is a bit on the weak side. Regardless, have
thunderstorm chances in for most of the day Thursday, with the
best chances in the southwest part of the CWA. Carried
thunderstorm mention in through the night Thursday into Friday
morning as the upper trough axis passes over the region.
Lingering showers will last through the morning on Friday, but the
remainder of the afternoon and overnight hours should be dry
across the mid state. Long term models diverge a bit during the
day Saturday, but have a weak shortwave move through the area and
should provide enough lift for some scattered light showers
initially. By the afternoon and evening Saturday, a very strong
closed low will move across TX and will be the next big system for
the remainder of the weekend. An interesting shortwave develops on
the GFS, and is much weaker on the ECMWF, which looks to intensify
the thunderstorm potential over the area. The GFS has much more
instability compared to other models as well, but the consensus
has the track of the upper closed low to stay south of the region.
This should keep severe chances mainly to the south, but if the
shortwave solution pans out, would not rule out the chance for
some strong to severe storms Saturday afternoon and evening. Since
the ECMWF is a bit slower and has a weaker shortwave with the
current runs, will have to see which solution wins out over the
next few days.
Sunday also has the potential for some stronger storms, again with
the GFS solution. Other models like the ECMWF are not on board
just yet. Still have thunderstorms in for Sunday, and likely pops
are in the forecast from Saturday afternoon through early Monday
morning across the area. With the slow churning upper low, and
plenty of moisture, we should see some good rainfall this weekend.
Showers look to hang around on Monday and early Tuesday before
drier air finally moves in with the upper ridge on Wednesday. The
GFS and ECMWF are hinting at colder air moving in with the next
trough next Thursday, so if that trend continues, our run at above
average temps will come to an end late next week.
00Z TAF DISCUSSION.
There`s going to be a mish-mash of aviation categories tonight as
our current frontal system starts to work its way out of the
region. KCSV/KBNA look to get the worst of it with at least MVFR
flight rules and several hours of IFR through the night. KCKV
should see MVFR later this evening. All 3 mid-state terminals
will begin to improve late tomorrow morning.
Winds will be relatively light out of the west this evening before
shifting to the north in the morning.