Area Forecast Discussion
Issued by NWS Nashville, TN

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FXUS64 KOHX 272329

Area Forecast Discussion
National Weather Service Nashville TN
629 PM CDT Thu Jul 27 2017



(Tonight-Sat Night)

Will be making some tweaks here and there as press time
approaches, and more than likely will break out a later afternoon
zone grouping. SPC has backed off the potential for strong to svr
tstms for tonight and again on Fri as overall system dynamics
associated with, at least initially thought, to be a stronger
than normal summertime cold frontal passage, do not look like
they will actually occur at this point. So all in all, general
tstms are anticipated tonight and into Fri. Still, can not rule
out a few strong tstms developing, with strong gusty straight-line
winds the main concern. Precip water values will generally be
around 2 inches thru period, and some brief heavy downpours
associated with the stronger tstms could also be possible.
These stronger tstms could leading to localized ponding of water
on roadways and minor flooding of known flood prone locations.
However, do not anticipate at this time any widespread organized
flooding potential. Expecting increasing coverage of shwrs/tstms
beginning in the nw after 28/00Z with bulk of the mdt rainfall
moving into wrn portions of mid state at or just after 28/06Z.
Rainfall coverage will then spread generally sewd into
southeastern portions of mid state as the mid into late morning
hrs progress. An approaching upper level shortwave ahead of sfc
frontal passage will play a focusing role also along with low
level moisture pooling ahead of sfc frontal passage tonight and
into Fri. In agreement with latest WPC Model Diagnostic Discussion
Reasoning, leaning toward a 27/12Z GFS & 27/12Z EURO blend. Will
do best to depict timing/impacts in hrly grids. Thus, current sfc
front located across srn Ohio River Valley as of 27/18Z will push
close to nw portions of mid state by 28/12Z and then push into
southeastern portions of the mid state by 29/00Z. As a result,
will expect locations across wrn portions of mid state to
experience numerous light/mdt shwrs and tstms by 29/06Z with this
potential across most of the mid state thru the morning hrs on
Fri. Enhanced moisture in vcnty of sfc front will keep the chance
of shwrs/tstms going thru the mid afternoon hrs on Fri. Some
lingering light shwrs/tstms may persist into Fri evening also.

However, a significant change to the air mass is expected as the
first part of the weekend progresses, as above mentioned sfc
front will have pushed well south of our region by Sat morning.
Strong high pressure influences centered across wrn portions of
the Great Lakes Region will build into our area. Dry and
seasonably pleasant wx along with ptcldy skies will be in store
Sat into Sat night across our area.

As for temps, seasonably warm lows will continue tonight with
lows mainly in the lower 70s. The end to the heat index readings
in the afternoon hrs ranging from the upper 90s to lower 100s will
come to and end as of Fri afternoon. Highs will generally be in
the mid 80s, upper 70s to lower 80s Cumberland Plateau Region on
Fri. afternoon. As above mentioned sfc high pressure influences to
our north build into the mid state region, temps will actually
drop to a few degrees below seasonably normal values, with lows in
the mid to upper 60s, lower 60s Cumberland Plateau Region on Fri.
night. Highs on Sat will be on average 5 to 7 degrees below
seasonal normal values, great for outdoor summer activities.
Highs on Sat will range in the lower 80s, mid 70s to approaching
80 Cumberland Plateau Region. Lows Sat night will be seasonably
cool, with lows mainly in the lower 60s, and even into the upper
50s Cumberland Plateau Region.


Broad upper level ridging will persist across wrn portions with
broad upper level troughing across ern portions of the
contiguous U.S. thru the long term period. 27/12Z GFS showing
overall more enhanced upper level troughing influences across ern
portions of contiguous U.S. as compared to 27/12Z ECMWF. Sfc
pattern showing apex of broad high pressure influences shifting
from wrn portions of the Great Lakes Region on Sun slowly sewd
into the cntrl Appalachians by Thu. However, these broad high
pressure influences will continue wwd across most of the
contiguous U.S. next work week. Whatever model preference you
prefer here, will continue lean toward blended 27/12Z GFS/EURO
solution, dry conditions with generally moclr skies will be
prevalent Sun thru Tue night. With the potential, especially as
the 27/12Z GFS advertises, of increased upper level troughing
influences, ptcldy skies with diurnal driven typical summertime
iso light/mdt shwrs and tstms will be possible Wed and again on

As for temps, afternoon highs on average will be around 5 degrees
below seasonal normal values by Sun afternoon. Highs will
generally be in the lower 80s, upper 70s to around 80 Cumberland
Plateau Region. However, temps will quickly warm as the first part
of next work week progresses, with temps around seasonal normal
values persisting into mid to later portions of next work week.



Flying conditions will deteriorate over the taf period as a cold
front approaches from the northwest. Some shower and storm
activity could impact CKV, BNA, and MQY before 6z tonight.
Afterwards, scattered showers are still possible for all
terminals. Widespread showers and storms should redevelop tomorrow
ahead of the front. Winds will be SW and eventually veer to the NW
as fropa occurs.





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