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000
FXUS64 KEWX 121748
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1248 PM CDT Wed Aug 12 2020

.AVIATION...
All airports will be VFR through the afternoon and evening. Winds
during the afternoon will be a bit gusty, up to 25 kts. There was
less cloudiness this morning and models suggest even less Thursday
morning, but we are not convinced there will not be any ceilings. We
have included TEMPO MVFR in Austin and San Antonio for a few hours
after sunrise.

&&

.PREV DISCUSSION... /ISSUED 330 AM CDT Wed Aug 12 2020/

SHORT TERM (Today through Thursday)...
The main concern in the short term portion of the forecast will be
centered on the increasing temperatures. It will be hot again today
as the subtropical ridge axis in the mid and upper levels, along
with a stout low-level thermal ridge remain the dominant weather
feature of interest. Trends over the last couple of days show low-
level moisture has not been able to not mix out quite as efficiently
for areas along and east of I-35. Thus, we have seen afternoon
dewpoints trend upward during the peak heating hours. The latest
model guidance does show some higher dewpoints remaining intact
today. With afternoon temperatures expected to remain persistent or
even increase slightly, we will likely meet Heat Advisory levels for
areas along and east of the I-35/I-37 corridor. We will issue a Heat
Advisory for the above mentioned areas from 1 PM - 7 PM today. It
will be hot again tomorrow and we may very well need another Heat
Advisory for portions of south central Texas. Otherwise, it looks
too stable aloft to support any rain chances across the region and
we will keep the forecast dry through Thursday.

LONG TERM (Thursday Night through Tuesday)...
Subtropical Ridge remains centered over southern Arizona/New Mexico
through Friday, then gradually shifts to the Four Corners and builds
north into the Great Basin this weekend, all the while extending over
Texas. Strong subsidence under the Ridge and below seasonal normal
moisture levels (PWs) make for no rain over most areas. An inverted
trough passing well south of our area across Mexico brings a slight
increase in moisture to near seasonal levels to the Coastal Plains
this weekend. This may allow the seabreeze to generate a few showers
and thunderstorms across Lavaca and possibly nearby counties during
the afternoon hours. Well above normal temperatures continue. A few
spots along and east of I-35 may briefly flirt with advisory levels
with both high temperatures and heat index values.

The portion of the Ridge over Texas weakens as upper level troughing
develops over the eastern states Monday and Tuesday. This may allow
a surface boundary or weak mid level impulses to move across our
area. Will maintain the low chances of showers and thunderstorms as
these features provide the upward forcing needed on slightly deeper
moisture. With the increased cloud cover and rain, high temperatures
may cool 2 or 3 degrees on Monday and even more on Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              78 103  77 104  77 /   0   0   0   0   0
Austin Bergstrom Intl Airport  77 101  77 102  75 /   0   0   0   0   0
New Braunfels Muni Airport     76 100  76 103  75 /   0   0   0   0   0
Burnet Muni Airport            76 100  76 103  75 /   0   0   0   0   0
Del Rio Intl Airport           79 103  79 106  78 /   0   0   0   0   0
Georgetown Muni Airport        78 102  78 102  77 /   0   0   0   0   0
Hondo Muni Airport             76 101  76 105  75 /   0   0   0   0   0
San Marcos Muni Airport        77 101  76 103  75 /   0   0   0   0   0
La Grange - Fayette Regional   78 101  78 102  77 /   0   0   0   0   0
San Antonio Intl Airport       78 101  77 103  76 /   0   0   0   0   0
Stinson Muni Airport           77 101  77 102  76 /   0   0   0   0   0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT this evening for Atascosa-Bastrop-
Bexar-Caldwell-Comal-De Witt-Fayette-Gonzales-Guadalupe-Hays-Karnes-
Lavaca-Lee-Travis-Williamson-Wilson.

&&

$$

Short-Term/Aviation...05
Long-Term...Oaks
Decision Support...KCW