Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 08/17/23
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
639 PM CDT Wed Aug 16 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Thursday night)
Issued at 201 PM CDT Wed Aug 16 2023
Synopsis/Mesoanalysis: The remains of the early week front are
washing out early this afternoon as winds turn south-southeasterly
over the Rio Grande Plains and southern Edwards Plateau. What`s left
of the boundary remains evident in weak surface convergence, in
addition to a mainly east-west dew point gradient from Hill Country
south into the Victoria Crossroads. Latest surface observations
place the decaying boundary along an approximate Beeville-
Castroville-Junction line. Cumulus have been noted over the last 1-2
hours along & southwest of the surface boundary, with the most
focused development being observed over Brush Country and in
Edwards/Real Counties. Some of said cumulus is likely to deepen into
shower and thundershower activity by late afternoon, drifting
southwest through the first portion of the evening hours. The 594-
596 dam upper anticyclone currently centered over the Four Corners
region is forecast to shift east into the Red River Valley tomorrow,
resulting in increasing high temperatures locally. Heat headlines
for Thursday have been issued in the afternoon update, with all
South-Central Texas counties being included in at least a Heat
Advisory. Critically to extremely dry fuels and very low relative
humidities will continue to support elevated to near-critical fire
weather conditions through the duration of the short term period.
Please refer to the Fire Weather section below for additional
details regarding the fire weather potential.
Rest Of Today & Tonight: Isolated to widely scattered
shower/thunderstorm development remains anticipated along and west
of the decaying surface front. Activity should form by mid-late
afternoon, likely dissipating by mid-evening as the boundary layer
stabilizes. Have carried slight chance PoPs over the majority of the
Rio Grande Plains, as well as western portions of Hill Country and
the southern Edwards Plateau, where proximity to the boundary is
greatest and cu development has been most prominent early this
afternoon. Activity is likely to remain widely scattered in nature,
so widespread beneficial rains continue to appear unlikely. Forecast
soundings from the HRRR, as well as the current ACARS sounding from
San Antonio Intl indicate a deep subcloud layer with large dew point
depressions, so gusty outflow winds will be possible as updrafts
collapse. Heat Advisories remain in effect for most locations
outside of Hill Country through 9 PM, given a combination of 108-110
degree heat indices across the west and air temperatures at/above
103 elsewhere. Continue to practice proper heat safety if spending
prolonged periods of time outdoors in these areas.
Tomorrow: Very hot high temperatures are forecast over the entirety
of South-Central Texas. 105+ degree highs are expected in most
locations outside of Hill Country, where temps should top out in the
102-104 range. This temperature forecast has prompted the issuance
of an Excessive Heat Warning along and east of Interstate 35, as
well as in Llano and Burnet Counties. Heat Advisories have been
issued for our Hill Country zones, as well as our higher criteria
counties in the Rio Grande Plains. All heat products will be in
effect between noon and 9 PM Thursday evening. Drink plenty of
water, wear light-colored & loose-fitting clothing, and take
frequent breaks in shaded/air-conditioned environments if planning
to be outside tomorrow. Check up on family and friends, and never
leave children & pets unattended in vehicles.
&&
.LONG TERM...
(Friday through Wednesday)
Issued at 201 PM CDT Wed Aug 16 2023
The upper level ridge will continue to move toward the northeast
into the central Plains Friday into the weekend. Southerly low level
flow will strengthen Friday, leading to renewed fire weather
concerns. With the upper high centered to our north temperatures will
be slightly less hot starting Saturday, it will continue to remain
hot and mainly dry through the weekend across South Central Texas,
with heat headlines likely.
We continue to watch for the possibility of a tropical wave over the
Gulf of Mexico sliding west, beneath the ridge, and into Texas
sometime during the early to middle portion of next week. Models
continue to show this feature, but a large spread in timing and
location. Chances for showers and thunderstorms spread in from the
southeast starting Monday and continue through the end of the
period.
&&
.AVIATION...
(00Z TAFS)
Issued at 634 PM CDT Wed Aug 16 2023
VFR conditions are forecast at area TAF sites through the current
forecast period. Isolated convection across the Rio Grande plains
will slowly weaken as daytime heating begins to decrease. With
coverage very limited, we will not mention any SHRA or TSRA at DRT
this evening. Otherwise, some limited moisture return may lead to
stratus development along I-35 toward sunrise. For now, confidence is
low in MVFR and will keep coverage at FEW for now. Afternoon cumulus
development should take place again tomorrow afternoon, with
forecast soundings showing moisture levels higher out west along the
Rio Grande.
&&
.FIRE WEATHER...
Issued at 201 PM CDT Wed Aug 16 2023
Low afternoon relative humidities ranging from the upper teens to
mid 20s remain forecast this afternoon. Sustained 20 foot winds are
expected to remain light, although brief/isolated 15-20 MPH gusts
are possible. A Fire Danger Statement thus remains in effect across
all of South-Central Texas until 9 PM this evening. Minimum
humidities are expected to fall into the upper teens over most
locations outside of the Coastal Plains on Thursday afternoon,
although sustained 20 foot winds are once more expected to remain
light through the period of lowest humidity. Winds will likely
increase during the early to mid evening as the sea breeze advances
inland, though recovery will be in-progress. It thus remains
uncertain if Red Flag Warnings will be needed tomorrow afternoon, or
if a Fire Danger Statement will sufficiently address the fire
weather potential. Final decisions regarding Thursday`s fire weather
headlines will be coordinated with neighboring offices tonight.
Residents across all of South Central Texas are urged to continue to
exercise extra care with any outdoor activities that could
inadvertently ignite wildfires.
&&
.CLIMATE...
Issued at 201 PM CDT Wed Aug 16 2023
Record High Temperatures
8/17 8/18 8/19 8/20
Austin Camp Mabry 107 109 107 106
Austin Bergstrom 105 104 106 105
Del Rio 109 107 108 106
San Antonio 104 105 108 107
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 77 108 78 108 / 0 0 0 0
Austin Bergstrom Intl Airport 74 107 75 106 / 0 0 0 0
New Braunfels Muni Airport 75 106 74 107 / 0 0 0 0
Burnet Muni Airport 75 107 77 107 / 0 0 0 0
Del Rio Intl Airport 81 108 80 108 / 20 0 0 0
Georgetown Muni Airport 75 107 78 107 / 0 0 0 0
Hondo Muni Airport 76 106 75 105 / 20 0 0 0
San Marcos Muni Airport 74 107 73 106 / 0 0 0 0
La Grange - Fayette Regional 75 106 75 104 / 0 0 0 0
San Antonio Intl Airport 78 106 77 105 / 0 0 0 0
Stinson Muni Airport 77 107 75 106 / 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from noon to 9 PM CDT Thursday for Atascosa-
Bastrop-Bexar-Burnet-Caldwell-Comal-De Witt-Fayette-Frio-Gonzales-
Guadalupe-Hays-Karnes-Lavaca-Lee-Llano-Medina-Travis-Uvalde-
Williamson-Wilson.
Heat Advisory until 9 PM CDT this evening for Atascosa-Bastrop-
Bexar-Caldwell-Comal-De Witt-Dimmit-Fayette-Frio-Gonzales-Guadalupe-
Hays-Karnes-Kinney-Lavaca-Lee-Maverick-Medina-Travis-Uvalde-Val
Verde-Wilson-Zavala.
Heat Advisory from noon to 9 PM CDT Thursday for Bandera-Blanco-
Dimmit-Edwards-Gillespie-Kendall-Kerr-Kinney-Maverick-Real-Val
Verde-Zavala.
&&
$$
Short-Term...Gale
Long-Term...Platt
Aviation...Gale