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000
FXUS64 KEWX 210013
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
713 PM CDT Sat Apr 20 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 649 PM CDT Sat Apr 20 2024

A quick update issued to reduce the fog potential and clean up some
of the PoP/WX/Temp/Dew Point trends. San Antonio area continues to
under-perform what the rapid refresh models had in store, but late
evening to around 1 AM should be their best opportunity to get storms
and heavy downpours. A low end severe threat for mainly hail
continues this evening for most areas.

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 143 PM CDT Sat Apr 20 2024

We`ll continue to monitor two main areas for additional shower and
thunderstorm development through the afternoon and evening. The
first area is across the Coastal Plains and portions of the I-35
corridor where southerly warm air advection continues around 850mb.
This has already led to the development of some light streamer
showers over the last few hours, and the potential for thunderstorms
will continue to increase due to both increasing lift and
instability in advance of a 500mb shortwave moving in from the west.
The other area we`ll be monitoring is the ongoing convection across
the Big Country which is expected to continue to develop and push
south/east into the Edwards Plateau and Hill Country in the coming
hours. The upper level shortwave and a reinforcing shot of cooler
air at the surface will both push convection south and east across
the area this evening and overnight, with generally dry conditions
expected by the daytime hours Sunday.

As far as the thunderstorms that are expected over the next 12 hours
or so, both shear and instability parameters continue to support a
marginal severe threat (isolated hail and damaging wind gusts).
Additionally, there is a slightly more concerning heavy
rainfall/flash flood threat with PWATs generally ranging from 1.5-
1.7" across south-central Texas. We are not confident that instances
of flooding will be widespread enough to warrant the issuance of a
Flash Flood Watch, but isolated pockets of 3+" inches could cause
some localized issues. While heavy rainfall will be possible with
any thunderstorm, the HREF Probability Matched Mean continues to
favor eastern portions of our CWA for the greatest rainfall amounts.

As mentioned above, the daytime hours on Sunday are looking dry,
though mostly cloudy skies and a decent northeasterly breeze will
make for a chilly day (at least for this time of year) with highs
across northern and eastern areas only in the 60s. Lows will dip
into the 40s and 50s areawide for Monday morning

&&

.LONG TERM...
(Monday through Saturday)
Issued at 143 PM CDT Sat Apr 20 2024

A mid-level ridging pattern establishes much of next week across
South-Central Texas while within the lower levels of the atmosphere
a light to moderate south-southeasterly onshore flow returns with
surface high pressure sliding to the east. With the southerly flow,
steady moisture recovery will be expected through early week as dew
points climb into the mid to upper 60s by Wednesday afternoon. The
dew points remain high through the rest of the period. An uptick in
cloud cover along with occasional stray opportunities for light mist
or drizzle may evolve mid to late week with the low-level moisture
advection coming off the gulf. A pair of upper level systems pushing
into or across the Four Corners region late week into the weekend
could help to induce slightly better opportunities for shower and/or
convection at the end of the forecast period across northeastern
most counties. Some differences exist in the medium range guidance
on these systems but those details will be ironed out with time in
the days ahead. Afternoon highs will steadily rise through the long
term with values into the mid 80s to mid 90s by Friday and Saturday.
Overnight lows also rise back into the 60s and even the low 70s by
the end of the period as well.

&&

.AVIATION...
(00Z TAFS)
Issued at 649 PM CDT Sat Apr 20 2024

With radar trends not reflective of the rapid refresh runs around San
Antonio, have removed the prevailing VCTS with the anticipation of a
TS event lasting maybe an hour or two. Multiple rounds of TS are
still possible around AUS so we went with prevailing TS after 01Z and
running through around 06Z. Conditions should improve rapidly at DRT
after 01Z, but some elevated shower activity could continue to hold
down the cigs into MVFR through the night. Significant improvements
on the VSBY impacts from convection should reach the I-35 corridor by
around 06Z, but some isolated shower cells could briefly lower VSBYs
below 3 miles through the night. After daybreak a slow lifting of
CIGs should get everyone into VFR cigs by midday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              52  65  49  73 / 100   0   0   0
Austin Bergstrom Intl Airport  51  65  46  72 / 100   0   0   0
New Braunfels Muni Airport     53  66  48  74 /  90   0   0   0
Burnet Muni Airport            50  63  47  72 / 100   0   0   0
Del Rio Intl Airport           60  72  57  76 /  50  10  10   0
Georgetown Muni Airport        50  64  45  70 / 100   0   0   0
Hondo Muni Airport             54  69  49  74 /  70   0   0   0
San Marcos Muni Airport        51  65  46  73 /  90   0   0   0
La Grange - Fayette Regional   54  65  47  72 /  90  10   0   0
San Antonio Intl Airport       54  66  50  73 /  90   0   0   0
Stinson Muni Airport           56  68  52  74 /  80   0   0   0

&&

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

$$

Short-Term...18
Long-Term...Platt
Aviation...18