Scientific Forecaster Discussion
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Area forecast discussion...updated
National Weather Service Austin/San Antonio Texas
656 PM CDT Tue Aug 20 2019
please see the 00z aviation forecast discussion below.
a few light showers continue mainly east of I-35 as of early this
evening. This activity will continue to decrease with the loss of
daytime heating and we will not mention any rain showers in the current
forecast. Otherwise, some gusty southeast winds are in store for the
I-35 sites this evening, with winds decreasing after midnight. Low
cloud development is also expected and we will mention prevailing
MVFR cigs at Sat and ssf beginning 07-08z. Low clouds do not appear
quite as favorable for aus tomorrow morning and will only mention scattered
clouds for now. We will need to monitor the 12-14z period at aus as
this time frame may provide the best chance low cloud development.
Improvement is then expected after 14z and Sat and ssf. For drt, we
will keep the forecast VFR through the period as gusty southeast
winds continue for the next several hours, then decrease and back to
a more easterly direction after 03z. We will not mention any low
clouds at drt, but could see some scattered low clouds not too far east of
the terminal after 13z.
Previous discussion... /issued 238 PM CDT Tue Aug 20 2019/
Short term (tonight through Wednesday night)...
partly cloudy skies prevail for most of the area at this time with
temperatures in the middle to upper 90s. Overall, temperatures are
about a degree or two cooler than this time yesterday with some sites
unchanged. Scattered showers and storms will continue across the
coastal plains this afternoon aided by a weak inverted coastal
trough. There is a small chance that some of these could sneak
closer to the i35 corridor by late this afternoon. For tonight,
another dry night with lows in the middle to upper 70s can be
expected for most of the area. For tomorrow, the ridge is expected to
continue to break down which should allow high temperatures to be
another degree or two cooler than today. The inverted trough axis
will be west of the region and the overall coverage of showers and
storms will be less as a result.
Long term (thursday through tuesday)...
expect continued low chances of showers and storms on Thursday and
Friday mainly east of i35 in the afternoons. Highs will continue to
be in the upper 90s to 102 degrees with the warmer temperatures
closer to the Rio Grande. Medium range models then diverge with their
solutions beginning on Saturday which will then have subsequent
impacts on the remainder of the forecast period. The GFS/European model (ecmwf) both
develop a weak low across northern Mexico on Saturday but the GFS is
much stronger and moves it east as it gets picked up in the longwave
trough axis moving across the Central Plains. If the GFS were to
verify, Saturday afternoon and evening could be wet in the west with
the rest of the area seeing decent chances of rain on Sunday.
However, the European model (ecmwf) keeps this system much weaker and does not show it
getting picked up in the eastward moving trough. Therefore its
forecast for the weekend and beyond is much drier than that of the
GFS. Because the development and movement of this low is highly
dependent on several factors, will lean closer to the drier European model (ecmwf) for
now and only forecast 20/30 pops. This system will also have an
impact on the temperature forecast as well. Will continue with low
pops through Tuesday with the possible increased moisture.
Preliminary point temps/pops...
Austin Camp Mabry 78 99 77 99 77 / 0 - 0 10 -
Austin Bergstrom Intl Airport 76 98 76 98 75 / 0 10 0 10 -
New Braunfels Muni Airport 75 97 74 98 74 / - - - 10 -
Burnet Muni Airport 75 97 74 97 74 / 0 - 0 - -
del Rio Intl Airport 78 101 77 101 77 / 0 0 0 - -
Georgetown Muni Airport 77 99 76 99 76 / 0 - 0 - -
Hondo Muni Airport 75 101 74 101 74 / 0 - - - 0
San Marcos Muni Airport 76 99 75 98 75 / 0 - - 10 -
La Grange - Fayette regional 77 99 76 98 77 / 0 10 0 20 -
San Antonio Intl Airport 78 98 77 98 77 / - - - 10 -
Stinson Muni Airport 77 99 77 98 77 / 0 - - - -