Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
FXUS64 KEWX 280536
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1236 AM CDT SUN AUG 28 2016
All terminals are currently VFR and this should continue for the
next several hours. Intermittent MVFR CIGs will develop in the
San Antonio area by around 11Z and have included a TEMPO group
until 14Z. Expect only SCT low clouds at AUS and DRT. Convection
will develop this afternoon in the Austin and San Antonio areas,
but timing and extent are uncertain. So, have included PROB30
groups to account for it between 20Z and 24Z. Any storms should
not lower category.
.PREV DISCUSSION... /ISSUED 253 PM CDT SAT AUG 27 2016/
SHORT TERM (Tonight through Sunday Night)...
Over the course of the afternoon, isolated showers with occasional
lightning activity were developing and slowly moving westward.
Taking a look at the mesoscale environment...it appears RAP is
undergoing the low level instability and lapse rates over the
northern Hill Country and northwest towards Midland. 19Z
observations were showing temperatures already in the 90s just
north of the CWA border which is likely aiding in the added
convective potential over 60s dewpoints. Will have to watch for
some gusty wind potential and gust front generation fueling
development over the next several hours due to DCAPEs over 1000
j/kg as well as mid level dry air. PWATs across the CWA are in
the 1.5-1.8 inch range which is notably low relative to our
average over the last few weeks but the added convective potential
could still result in some brief heavy rainfall. Should see this
activity wane shortly after dark.
Coverage of QPF will increase across the CWA Sunday as the weak
gulf disturbance centers itself south of Galveston Bay. PoPs will
still favor the southeast quarter of the CWA but at least isolated
convection should occur to the Rio Grande Plains.
LONG TERM (Monday through Saturday)...
By Monday, the disturbance slowly rides the Texas coastline
southwest keeping PoP chances elevated across the CWA. PWATs will
have increased to around 2 inches as far west as the Rio Grande
thus increasing the potential for locally heavy rainfall. However,
this latest suite of model runs is overall keeping QPF output
rather low. Still maintain that some isolated spots...most likely
east of I-35...could see a couple inches of rain between now and
next Wednesday. But in general, the rainfall totals should stay
between a half inch to an inch over the next 5 days.
The upper low begins to lose continuity by midweek and with it the
loss of deep layer moisture over the region. The GFS depicts a
rather dry air mass filtering into South Texas by Friday morning
and riding up the Rio Grande Valley and Plains in central Texas by
next Saturday. This should serve to remove rain chances from the
forecast for next weekend. The main upper high begins to build as
well bringing highs back into the mid 90s by the end of the
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 88 73 89 74 88 / 40 30 50 30 40
Austin Bergstrom Intl Airport 88 73 89 73 89 / 40 30 50 30 40
New Braunfels Muni Airport 88 73 89 72 89 / 40 30 50 30 50
Burnet Muni Airport 87 72 88 71 88 / 30 30 40 30 40
Del Rio Intl Airport 93 74 91 73 90 / 20 20 40 30 40
Georgetown Muni Airport 88 73 88 73 88 / 30 30 40 20 40
Hondo Muni Airport 91 73 90 73 90 / 30 20 50 30 50
San Marcos Muni Airport 88 72 88 72 89 / 40 30 50 30 40
La Grange - Fayette Regional 88 74 90 74 90 / 50 30 50 30 50
San Antonio Intl Airport 89 74 89 74 89 / 40 30 50 30 50
Stinson Muni Airport 91 75 90 75 90 / 40 30 50 30 50