Scientific Forecaster Discussion
fxus64 kewx 202008
Area forecast discussion
National Weather Service Austin/San Antonio Texas
308 PM CDT Fri Sep 20 2019
Short term (tonight through Saturday night)...
isolated to scattered showers and thunderstorms continue this
afternoon for areas near the coastal plains. Deeper moisture along
with the sea breeze will favor rain chances for areas generally along
and east of the I-35/I-37 corridors through early evening. However,
we could see some isolated activity near I-35 and will keep a low
chance in the forecast through early evening. With the loss of
daytime heating, most activity is expected to decrease. For the
overnight hours, the strengthening low-level jet will promote the
development of a few streamer showers over The Hill Country, I-35
corridor and coastal plains. Overnight lows will remain well above
normal, given southerly flow in the low-levels. Most areas will
remain in the in the 70s, with a few readings in the upper 60s over
The Hill Country.
Little change in the overall pattern is anticipated on Saturday. We
could see some isolated to scattered showers and storms, mainly
during the afternoon hours for areas generally along and east of
Highway 281. It will be warm again on Saturday, with highs generally
in the 90s. With humid conditions in place, afternoon heat index
values will rise to around 105 degrees along and east of I-35.
Long term (sunday through friday)...
above normal temperatures will continue for Sunday into early next
week as a subtropical ridge axis anchored over the southeastern U.S.
Will extend westward into the eastern and southern portions of Texas.
An upper level trough axis will pass to our north on Sunday, but will
likely not have an impact on our weather given the strength of the
upper level ridge. Temperatures through the middle of next week will
remain above normal with highs generally in the 90s and lows in the
upper 60s and 70s. We prefer to go with the warmer European model (ecmwf) guidance
numbers with respect to maximum and minimum temperatures. The upper
level ridge axis may weaken or re-center itself over the eastern Gulf
of Mexico as we head into the middle of the upcoming weak. This may
allow for deeper southerly flow in the mid-levels, which may bring a
slight uptick in precipitation chances. However, we prefer to keep
rain chances low at this time in case the subtropical ridge axis
remains stronger than anticipated.
For mid to late week, the medium range models continue to show an
upper low somewhere over the Desert Southwest or northern Mexico. The
models do eventually lift this system into the southern U.S. Plains,
but at this time it is advertised to remain too far north to offer
a great opportunity for rainfall. However, given a slightly more
active flow aloft, we will keep low rain chances in the forecast for
most areas for the mid to late week period. As for temperatures, we
do not see much relief given a warm a humid air mass maintaining it's
grip across the region.
Preliminary point temps/pops...
Austin Camp Mabry 76 98 74 95 74 / 20 20 - 10 -
Austin Bergstrom Intl Airport 75 96 73 94 72 / 20 20 - 20 -
New Braunfels Muni Airport 75 95 73 95 72 / 20 20 10 20 -
Burnet Muni Airport 74 92 72 93 71 / 10 20 - - -
del Rio Intl Airport 77 98 76 97 76 / 10 0 0 0 -
Georgetown Muni Airport 75 94 73 94 71 / 10 20 - 10 -
Hondo Muni Airport 76 98 74 98 72 / 10 20 10 10 -
San Marcos Muni Airport 75 95 72 94 71 / 20 20 - 20 -
La Grange - Fayette regional 75 95 74 94 73 / 10 30 - 30 -
San Antonio Intl Airport 77 95 75 95 74 / 20 20 10 10 -
Stinson Muni Airport 78 97 75 96 75 / 20 20 10 10 -