Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Austin/San Antonio Texas
1244 PM CDT Wednesday Jul 23 2014
Aviation... /issued for 18z tafs/
VFR conditions and light winds are expected through the taf
periods. Isolated showers and thunderstorms are possible over
parts of The Hill Country and coastal prairies early this
evening...but aside from a potential wind shift from outflows...
minimal impacts are expected over area taf sites. A complex of
thunderstorms is expected to move SW from the Arkansas-la-tex into
North Texas this evening. Some middle and upper level debris clouds
from the North Texas convection could spread into the area late
tonight into Thursday morning.
Previous discussion... /issued 1000 am CDT Wednesday Jul 23 2014/
a look the 12z drt/lch/crp soundings and NAM/GFS model soundings
for this afternoon all indicate potential for isolated convection
with minimally-capped profiles. However...moist air is sparse...
especially west of I-35. The latest NSSL and Texas tech wrfs show
convection over the coastal plains...mostly after 21z. Enhanced
convergence may also form one or two storms over the higher
terrain of the Edwards Plateau. Any storms have the potential for
outflow winds of 30-40 miles per hour. Overall...the current forecast is on
track so no changes.
Previous discussion... /issued 606 am CDT Wednesday Jul 23 2014/
VFR conditions are expected across area terminals through the
forecast period. Few/scattered deck around 4kft to 5kft is expected to
dominate for much of today. Variable winds this morning to become
easterly from midday to the evening with wind speeds of 5 to 10 knots.
Previous discussion... /issued 354 am CDT Wednesday Jul 23 2014/
Short term (today through thursday)...
the 23/00z upper air data showed the subtropical ridge axis was
centered over central New Mexico. The latest water vapor satellite
loop shows the ridge is expanding northward across the central
rockies early this morning. Short range models agree the ridge will
slowly expand northward through tonight...then flatten as an upper
low translates east across the southern Canadian provinces. With
the ridge remaining the dominant weather feature...expect
continued hot and humid conditions across south central Texas.
Heat indices may again approach 105 degrees for locations
generally south of U.S. Highway 90...so we will continue the
Special Weather Statement addressing this situation. There will be
a low chance for convection near the coastal plains today and
Thursday. We will retain a 20% chance for showers and
thunderstorms generally along and east of a Giddings to Karnes
City line. In addition...the hi-res models along with the sref
output remains consistent in showing low quantitative precipitation forecast across portions of
the southern Edwards Plateau and Hill Country. We will opt to
mention a 20% chance for convection across the mentioned region
for today. Some of the hi-res models also show a complex of
thunderstorms moving out of northeast Texas into portions of
central Texas late Wednesday night or very early Thursday morning.
Confidence is not yet high enough to mention rain chances just
yet...but this bears watching.
Long term (thursday night through tuesday)...
little change in sensible weather is expected through the
remainder of the work week into the upcoming weekend. Medium range
guidance suggests the subtropical ridge axis will continue to
dominate the weather pattern. A weak trough/shear axis may impact
the Upper Texas coast and south Texas Thursday night and Friday.
This feature will likely remain too weak and too far south to
bring any mentionable chance for precipitation to our region...so
we/ll keep the forecast dry for now. By early next week...the
ridge axis will retrograde into The Four-Corners region. This
along with a deepening trough over roughly the eastern half of the
Continental U.S. Will setup northwest flow aloft. The GFS...European model (ecmwf) and dgex
models are all showing a weak cold front across North Texas early
next week. Given decent agreement among the models...we/ll include
a slight chance for showers and thunderstorms across the northern
portion of our County Warning Area...including Burnet...Williamson and Lee
counties. Temperatures through the weekend will change little...
with highs in the middle 90s to near 100 degrees and overnight lows
in the 70s. We did show a slight decrease in temperatures for the
far northern portions of the County Warning Area next Tuesday to account for the
cold front and expected increase in cloud cover.
Preliminary point temps/pops...
Austin Camp Mabry 98 75 100 75 100 / 10 10 10 10 10
Austin Bergstrom international Airport 96 73 98 73 99 / 10 10 10 10 10
New Braunfels Muni Airport 99 73 100 73 99 / 10 10 10 10 10
Burnet Muni Airport 96 73 98 74 98 / 10 10 10 10 10
del Rio International Airport 100 78 101 78 101 / 10 10 10 10 10
Georgetown Muni Airport 96 74 99 75 99 / 10 10 10 10 10
Hondo Muni Airport 98 72 99 73 99 / 10 10 10 10 10
San Marcos Muni Airport 97 73 99 73 99 / 10 10 10 10 10
La Grange - Fayette regional 96 75 96 75 98 / 20 20 20 20 10
San Antonio International Airport 97 76 99 76 98 / 10 10 10 10 10
Stinson Muni Airport 99 75 99 75 98 / 10 10 10 10 10
public service/data collection...33