Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Austin/San Antonio Texas
639 PM CDT Sat Jul 4 2015
persistent pattern of morning IFR/MVFR ceilings...turning VFR in
the early afternoon. Like we have seen the past several mornings
the evening will turn mostly clear until shortly after midnight
when the stratus will form once again...hitting some IFR at
aus/Sat/ssf for a few hours around dawn. Ceilings go up with the
heating of the day and should go VFR most areas around noon or
slightly later. South winds in the morning...backing a bit to
southeast by the afternoon hours. Models are indicating a decent
breeze in the 12-16kt range for the afternoon...could get some
gusts over 20 knots.
Previous discussion... /issued 254 PM CDT Sat Jul 4 2015/
Short term (tonight through Sunday night)...
seeing some isolated shower and storm development east of i35 as
expected today. All convective and moisture parameters favor this
area until 00z. Hi res models advertise another loss of convection
as the evening progresses with a quiet overnight period in store.
For Sunday...similar conditions will exist compared to today in
the low levels. 20-30 knots 850 mb flow due to a subtropical high
over the eastern Gulf will continue to be in place with the best
deep layer moisture in the eastern County Warning Area. In the upper levels the
trough will continue east and result in variable upper level flow
as the ridge builds. The ridging effects will result in a slightly
more stable atmosphere tomorrow afternoon and forecast soundings
on the GFS/NAM both show a healthy cap at 750 mb at 18z. Erosion
of the cap is advertised in the NAM...which has been overdoing
convective potential...and the GFS holds it strong. Thinking
isolated showers and storms are still possible...but think this
will be pretty significantly confined to the coastal plains where
sea breeze convection may be able to lift parcels...but still not
too high on this potential either. Only slight chance probability of precipitation in the
forecast for this area.
Long term (monday through saturday)...
the ridge pattern over the SW Continental U.S. Will undergo some shortwave
deformations and influences Monday night and again Wednesday
night. The amplification of the shortwaves is beefier in the
GFS...which would lead to the potential for any potential mesoscale convective system
generation or linear system to progress farther south...should one
occur Wednesday night. At this time...no synoptic model suggests
this will occur...but its something to keep an eye on...especially
if mesoscale features not captured by the synoptic models is also
at play. As confidence is very low...no adjustment was made to the
pop chances...but thought this may at least be Worth mentioning.
Otherwise a much drier period is in store for the week. The long
range GFS advertises central Texas being directly under the center
of the summertime ridge and should continue to dry out the
atmosphere. So it would appear that very isolated afternoon
convection will be the only precipitation opportunities for the extended.
Preliminary point temps/pops...
Austin Camp Mabry 76 92 76 92 75 / - 10 - - -
Austin Bergstrom international Airport 74 91 76 92 76 / 10 10 - - -
New Braunfels Muni Airport 74 90 75 91 75 / - 10 - - -
Burnet Muni Airport 74 90 75 91 74 / - 10 - - -
del Rio International Airport 76 93 76 95 77 / - - 0 - -
Georgetown Muni Airport 75 90 76 91 75 / - 10 - - -
Hondo Muni Airport 74 90 75 92 75 / - 10 0 - -
San Marcos Muni Airport 75 90 76 92 75 / 10 10 - - -
La Grange - Fayette regional 75 91 77 91 77 / 10 20 - - -
San Antonio International Airport 76 91 76 92 75 / - 10 0 - -
Stinson Muni Airport 76 91 76 92 76 / - 10 0 - -