Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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FXUS64 KEWX 231511

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1011 AM CDT Fri Aug 23 2019

Quick update to lower rain chances through the late morning hours
for the Coastal Plains based on latest radar trends. With additional
heating, still expect another round of scattered showers and
thunderstorms to spread into the Coastal Plains along the sea breeze
this afternoon as an upper disturbance over the northwest Gulf
wobbles towards the Texas coast. Morning radiosonde observations
showed a mid-level trough axis around 500 MB located across West
Central Texas with a secondary area for thunderstorm development
expected this afternoon and evening in the vicinity of this feature.
Based on preliminary inspection of 12Z guidance and the presence of
this mid-level feature, have bumped up rain chances for the western
Hill Country for this afternoon and evening. As was noted in the
early morning forecast discussion appended below, stronger cells this
afternoon and evening will be capable of gusty winds.


.PREV DISCUSSION... /ISSUED 626 AM CDT Fri Aug 23 2019/

MVFR cigs were in place along I-35 this morning. The MVFR cigs will
lift and become VFR 13Z-15Z. VFR conditions will prevail outside
convection through this evening. Overnight expecting to see MVFR cigs
redevelop 07Z-10Z and continue into Saturday morning 13Z-15Z. Light
S/SE winds this morning will become SE 9-13 knots after 16Z. Winds at
SAT/SSF could become gusty in the 00Z-05Z period. All locations will
see stronger winds in or near convection. Currently have only
KSSF/KSAT with VCSH for afternoon convection. Forecast will be
updated as convection develops and timing becomes more certain.

PREV DISCUSSION... /ISSUED 436 AM CDT Fri Aug 23 2019/

SHORT TERM (Today through Saturday)...
Area radar imagery shows some ongoing convection across the lower
Trans-Pecos region early this morning. Some slow eastward movement is
noted and given radar trends, we will add a low chance for showers
and storms through early this morning for the far western portion of
Val Verde county. Elsewhere, some weak convection in the form of
showers is noted across the coastal plains. This activity is drifting
northward and should primarily remain confined to the southern
portions of Lavaca and DeWitt counties.

A weak, upper trough over the northwestern Gulf of Mexico along with
at or above normal moisture levels should result in isolated to
scattered convection today across most of south central Texas. Rain
chances will be favored over the coastal plains and Highway 77
corridor as this area will remain in proximity to higher moisture
levels. We will also need to monitor ongoing activity over west
central Texas this morning as any remnant outflow boundaries will
aid in convective development this afternoon across portions of the
southern Edwards Plateau and western Hill Country. Forecast
soundings from around the region show high-based storms with a fairly
deep inverted-V profile. This along with precipitation loading in
the stronger storms will yield a threat for a few strong wind gusts
this afternoon. We will continue to mention this concern in the
latest Hazardous Weather Outlook.

While we should see most shower and thunderstorm activity decrease
with the loss of daytime heating, we could still see some activity
persist tonight across portions of the Hill Country and southern
Edwards Plateau. In addition, a few showers may also linger tonight
across the coastal plains with the nocturnal low-level jet

On Saturday, the upper trough over the western Gulf of Mexico will
slide eastward a bit as an upstream trough axis moves into western
Texas. We will continue to maintain at or above normal moisture
levels and expect another chance for isolated to scattered convection
across most areas. Highs on Saturday should remain at or just above
climatological normals for late August.

LONG TERM (Saturday Night through Thursday)...
For Sunday, an upper trough axis will move through the region. This
will nudge higher moisture levels to our east and should keep any
rain chances confined to the coastal plains. Temperatures will also
warm on Sunday as the low-level thermal ridge strengthens. Highs in
the mid 90s to near 105 degrees are expected.

For early next week, the medium range models agree in showing upper
level ridging building in from the west and northwest. This pattern
will bring above normal temperatures back to all areas along with dry
weather for most areas. The exception will be along the coastal
plains where an isolated shower or storm may develop during the
afternoon hours. The above normal temperatures along with humid
conditions will also bring increasing heat index values to all areas.

There is some disagreement among the medium range models with respect
to the southward progress of a cold front as we head into the middle
of next week. We will not adjust the forecast too much at this time
and will opt to mention a low chance for showers and storms for all
areas on Thursday. We will also keep temperatures at or above normal
until the models begin to show a little more agreement.


Austin Camp Mabry              99  77  97  78 100 /  20  10  20  10  10
Austin Bergstrom Intl Airport  97  75  96  77  99 /  20  10  20  10  10
New Braunfels Muni Airport     96  75  96  76  98 /  20  10  20  10  10
Burnet Muni Airport            96  74  96  75  98 /  20  10  20  10  10
Del Rio Intl Airport          101  78  98  77 102 /  20  20  20  20  10
Georgetown Muni Airport        98  76  98  77 100 /  20  10  20  10  10
Hondo Muni Airport            100  76  99  76 101 /  20  10  10  10  10
San Marcos Muni Airport        97  75  97  76  99 /  20  10  20  10  10
La Grange - Fayette Regional   97  76  97  77  99 /  30  10  30  10  20
San Antonio Intl Airport       98  77  97  78  99 /  20  10  20  10  10
Stinson Muni Airport           97  77  97  78  98 /  20  10  20  10  10




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