Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
FXUS64 KEWX 251153
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
653 AM CDT MON JUL 25 2016
Broken borderline IFR-MVFR ceilings are expected to prevail for
the next few hours at SAT/SSF before lifting to VFR conditions for
the rest of the morning and early afternoon. A disturbance over
east Texas that will slide to the west-southwest coupled with some
remnant outflow boundaries will cause scattered showers and
thunderstorms this afternoon and early evening at the I-35 TAF
sites. Hi-res models have bumped up the timing an hour or two, so
have included vicinity thunderstorms for AUS after 20Z and SAT/SSF
after 22Z. Vicinity showers have also been added later this
evening for a few hours just after sunset. Model trends have
expanded coverage a bit further southwest, but left rain chances
out at DRT for now where conditions should remain VFR.
.PREV DISCUSSION... /ISSUED 405 AM CDT MON JUL 25 2016/
SHORT TERM (Today through Tuesday)...
A weak mid level disturbance over Eastern Texas is forecast to
drift to the southwest into South Central Texas today and linger
through Tuesday. Deeper moisture with PWS 2+ inches currently to
our east spreads across our area later today into Tuesday. Solar
heating and the mid level disturbance provide upward forcing for
showers and thunderstorms to develop midday into afternoon as
convective temperatures are reached. Then, outflow boundaries
maintain them into this evening and possibly overnight. Convective
temperatures will be reached earlier in the day on Tuesday with
scattered to numerous showers and thunderstorms by afternoon. PWS
of 2 to 2.4 inches, storm motion vectors of 10 KTS or less, and
some training of cells may allow for locally heavy rains up to 3
inches this afternoon through Tuesday and may cause mainly urban
and small stream type flooding. Weak CAPE is forecast making
gusty winds possible with the stronger storms. However, wind shear
is almost non existent. Prior to convective development today,
temperatures will be similar to yesterday and combined with the
humid airmass, heat indices in the 105 to 108 range are expected
along and east of I-35 as well as across the Rio Grande. Clouds
and earlier development of rain on Tuesday makes for a "cooler"
day with lower heat indices.
LONG TERM (Tuesday Night through Sunday)...
The mid level disturbance lingers into Wednesday while an upper
level trough currently off the west coast of Florida moves to the
west across the Gulf of Mexico. Models are now showing less of a
consensus with this trough. Some keep it east of our area while
others merge it with the mid level disturbance on Wednesday.
Regardless, a moist airmass will be lifted to generate scattered
showers and thunderstorms. Similar to the short-term, locally
heavy rains and gusty winds are possible with the stronger storms.
By Thursday, the disturbance and trough transition into a shear
axis that lingers into this coming weekend. Moisture level
decrease a little with showers and thunderstorms becoming driven
by solar heating. Expect development mainly in the afternoon and
dissipation in the evening. Below normal temperatures mid week
will rise again to above normal late in the week and weekend.
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 100 77 94 75 95 / 40 40 60 30 50
Austin Bergstrom Intl Airport 99 76 93 74 94 / 40 40 60 30 50
New Braunfels Muni Airport 100 76 94 74 94 / 30 40 60 30 50
Burnet Muni Airport 96 75 92 73 93 / 40 40 60 30 40
Del Rio Intl Airport 103 80 97 77 97 / 10 20 50 20 40
Georgetown Muni Airport 96 75 92 74 93 / 40 40 50 30 40
Hondo Muni Airport 100 76 94 74 95 / 20 30 50 20 50
San Marcos Muni Airport 99 76 93 74 93 / 40 40 60 30 50
La Grange - Fayette Regional 97 76 93 75 94 / 50 40 60 30 50
San Antonio Intl Airport 99 77 93 76 94 / 30 40 60 30 50
Stinson Muni Airport 102 78 95 76 96 / 30 30 50 30 50