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

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FXUS64 KEWX 241136
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
636 AM CDT Mon Jun 24 2019

.AVIATION... /12Z TAFS/
The first few hours of the TAF periods are in good confidence with an
mvfr deck to linger around over the I-35 terminals through 15Z to 18Z
with the later low cigs hanging around SAT/SSF. DRT has been and
should continue to be vfr through the morning, but a few 2500 ft
clouds could pop up in the next few hours. Vfr cumulus clouds are
expected over most areas in the afternoon. Then in the evening,
conditions become more convection dependent, leading to some timing
issues and some possible mvfr cigs that occur in the proximity of the
convection. A cumulative assessment based on several CAMs models
would suggest that DRT and AUS have a higher chance of seeing a mid
to late evening round of storms with SAT/SSF to see the activity
closer to midnight. Will leave this timing as a general picture with
prevailings suggested at all sites except DRT, where there is a tempo
group.

&&

.PREV DISCUSSION... /ISSUED 615 AM CDT Mon Jun 24 2019/

UPDATE...
Drier and cooler air has moved into portions of Central Texas behind
an outflow boundary and have done a quick update to retrend
temperatures and dew points based on latest observations.

PREV DISCUSSION... /ISSUED 412 AM CDT Mon Jun 24 2019/

SHORT TERM (Today through Tuesday)...
A line of thunderstorms stretches from near Lake Buchanan all the
way to western Mississippi early this morning, pushing towards the
east/southeast. The KGRK radar depicted an outflow boundary roughly
along a Marble Falls to Tanglewood line. This feature was beginning
to outrun the main convection across Central Texas, save for the
westernmost storms located along Highway 281. As this outflow
continues to race ahead of this section of the line, expect an
overall weakening trend to occur. A few strong pre-dawn storms will
still be possible where water-loading of stronger updrafts occur,
creating the potential for isolated strong wind gusts. 1000-500 MB
thickness contours (which can be used to roughly assess steering flow
for these larger systems) indicate this east-southeast motion will
continue through the morning hours and will have to watch for at
least some transient training of storms as a result. A secondary
round of thunderstorms was also observed developing between D/FW and
Abilene within the vicinity of a surface cold front. Expect fairly
similar storm motion to what has been observed earlier this morning
with higher resolution guidance indicating that this activity may
make reach the northern counties by mid-morning.

An overall break in thunderstorms is expected by mid to late morning
but will have to watch how the aforementioned outflow boundary
evolves during the morning hours. Latest RAP guidance indicates that
it may stall near the Interstate 10 corridor, which would be an area
to watch as a potential focus for redevelopment with heating this
afternoon. BUFR soundings from Austin and San Antonio suggest that
convective temperatures will be difficult to reach and only have 20
PoPs in place for most of the region as a result. Soundings from San
Angelo, however, reveal a more supportive environment for
redevelopment this afternoon with convective temperatures in the
88-93 degree F range. As these temperatures are reached during the
afternoon hours, it looks like a secondary round of thunderstorms
develop across West Central Texas. Dry sub-cloud layers and steep 0-3
km lapse rates of around 8-9 C/km will enhance updraft/downdraft
acceleration and raise the risk for these initially discrete
thunderstorms to grow upscale/congeal as their cold pools develop.
Convection Allowing Models (CAMs) remain consistent in indicating
that a secondary thunderstorm complex does develop over West Central
Texas this afternoon and moves towards the Rio Grande tonight. Have
some concerns that this complex may pull a bit farther east than what
the CAMs are showing due to the orientation of the 1000-500 MB
thicknesses tonight and have highest rain chances stretching from the
western Hill Country towards the Rio Grande. The main threat with any
of these storms would be gusty winds as they move into the region
from the north.

Quasizonal flow becomes established in the wake of a trough moving
across the Central Plains today with subtropical ridging amplifying
over both western Texas and New Mexico and the eastern Gulf on
Tuesday. A few streamer showers Tuesday morning across the Coastal
Plains are expected to expand in coverage with a mid-level weakness
in the height field and daytime heating allowing for scattered
showers and thunderstorms to develop across much of the region.

Temperatures are expected to remain near to slightly above normal in
the short term portion of the forecast with highs in the upper 80s
to low 100s and lows generally in the 70s.

LONG TERM (Tuesday Night through Sunday)...
The relative weakness in the mid-level height field lingers along
the Texas coast through mid-week before shifting east into the
northern Gulf. A secondary shortwave trough rounds the West Texas/New
Mexico ridge on Wednesday and Thursday, dropping towards the lower
Texas coast by the beginning of the weekend. Medium range guidance
indicates this inverted trough persists over South Texas through the
end of the forecast period, possibly closing off at the beginning of
next week. The presence of this weakness may enhance shower and
thunderstorm coverage along the sea breeze for the Coastal Plains
counties each afternoon/evening Thursday through Monday. With NAEFS
and GEFS anomalies indicating mid-level heights and near-surface
temperatures are near to slightly below for this time of year, have
kept temperatures in the long term forecast close to climatology with
highs generally in the low to mid 90s and lows in the low to mid
70s.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              91  74  91  74  92 /  40  20  30  30  10
Austin Bergstrom Intl Airport  91  73  91  73  91 /  40  20  30  30  20
New Braunfels Muni Airport     92  74  90  73  91 /  40  20  40  30  10
Burnet Muni Airport            90  71  90  72  90 /  30  20  30  30  10
Del Rio Intl Airport           96  75  92  74  94 /  20  40  20  20  10
Georgetown Muni Airport        91  73  91  73  90 /  30  20  30  30  20
Hondo Muni Airport             94  74  93  73  93 /  30  30  40  30  -
San Marcos Muni Airport        92  73  91  73  91 /  40  20  40  30  10
La Grange - Fayette Regional   91  75  92  75  92 /  50  20  30  30  20
San Antonio Intl Airport       93  74  91  75  92 /  40  20  40  30  -
Stinson Muni Airport           93  75  91  74  93 /  40  20  40  30  -

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Aviation...Oaks
Short-Term/Long-Term...Huffman


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