Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Austin/San Antonio Texas
523 PM CDT Thursday Jul 2 2015
no major changes to the current aviation forecast. Showers across
south central Texas currently will dissipate in the next few hours
leaving the overnight hours precipitation free. Counting on low clouds
once again reforming by early morning with IFR/MVFR most
sites...turning to VFR by the afternoon.
Previous discussion... /issued 252 PM CDT Thursday Jul 2 2015/
Short term (tonight through Friday night)...
scattered showers will stream north from deep south Texas into south
central Texas along a moisture axis that will move north toward west
central Texas this evening. A brief thunderstorm or two will be
possible through 8 PM...but the expansion of the high pressure
ridge from the west and the westward expansion of the 700 hpa level
ridge from the Gulf is pinching away at available moisture and
leading to weaker and more short-lived cells. Stability should
take over after Sundown. Min temperatures tonight are likely to
be a degree or two warmer over those from this morning...since
there was a downdraft modified sea-breeze that cooled temperatures
early Wednesday evening which is not expected this evening.
Nevertheless with model guidance low level wind forecasts showing
a decrease in surface winds over Wednesday...will split between
persistence and the much warmer blended guidances.
A low amplitude shortwave dropping into the Red River valley early
Friday could add to some moisture and instability from convective
debris drifting south. Will account for the possible elevated
instability over southeast counties Friday where a weak sea-breeze
push could trigger convection...but the overall pattern should be
stable for most of south central Texas.
Long term (saturday through thursday)...
northerly flow aloft aided by the southward moving shortwave could
send a few outflows and moisture into central Texas while low level
Gulf moisture remains rich to support convection this weekend.
The nearly flow aloft patterns are often tricky...but the synoptic
scale model agreement on a significant stabilizing influence in
the middle levels should help prevent the escalation of the
convection into organized clusters. Will continue to run slight
chance to low end chance probability of precipitation...but the trends appear down from
earlier projections. Due to the moisture...most areas will see a
general flat trend on warming and drying conditions over the
weekend. The pattern is expected to further stabilize Monday as
the upper ridge axis continues to expand east. The warming
trend...already slowly underway over western counties...will then
expand east to the rest of our area by Monday. The above normal
moisture in the soils and vegetation should keep most areas in the
low to middle 90s through the extended...but the slightly more arid
areas to the west could flirt with triple digits possibly as early
Preliminary point temps/pops...
Austin Camp Mabry 75 91 75 91 76 / - 10 0 20 -
Austin Bergstrom international Airport 73 90 74 91 75 / - 10 0 20 10
New Braunfels Muni Airport 72 90 74 90 75 / 10 10 0 20 10
Burnet Muni Airport 72 90 73 90 74 / 10 10 - 20 -
del Rio International Airport 75 92 75 93 76 / 0 10 0 10 10
Georgetown Muni Airport 74 90 74 91 75 / - 10 0 20 -
Hondo Muni Airport 73 91 74 91 75 / 10 - 0 20 10
San Marcos Muni Airport 73 90 74 90 75 / - 10 0 20 10
La Grange - Fayette regional 74 92 75 90 76 / - 20 - 30 10
San Antonio International Airport 75 90 75 91 76 / 10 10 0 20 10
Stinson Muni Airport 74 91 75 91 76 / 10 10 0 20 10
public service/data collection...30