178
FXUS64 KEWX 111725
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1225 PM CDT Sat May 11 2024

...New AVIATION...

.UPDATE...
Issued at 951 AM CDT Sat May 11 2024

Have adjusted PoPs and temperatures through Sunday given the latest
model trends, despite still a bit uncertainty on the placement and
timing of convection. Main changes was to increase PoPs over the
coastal plains later this afternoon through this evening. Highest
pops look to arrive across vast majority of the region late tonight
into Sunday morning. Most widespread activity, however, may settle
just north of our CWA. Lowered PoPs later in the day on Sunday,
especially from San Antonio and westward. Rose temperatures some
Sunday afternoon with the drier forecast as well.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 215 AM CDT Sat May 11 2024

A closed low is located just west of the Four Corners region this
morning with subtle southwesterly flow over South Central Texas.
This upper low shifts eastward through the day, moving over the
Central Plains on Sunday. This feature and some weak ascent ahead of
it will lead to precipitation chances today through the weekend. For
today, rain chances remain on the low side through the morning,
although a light shower cannot be ruled out in the west. The better
chances come this afternoon and evening and continue through Sunday
supported by the advancing upper level shortwave. Any storms this
afternoon would likely be elevated and there remains a low end
potential for a strong to severe storm in the western half of the
area with hail and damaging wind the main threat. If any storms form
in Mexico and move across the Rio Grande this evening, an isolated
tornado threat would also be possible. Precipitation chances continue
overnight mainly in the 40 to 50 percent range with better chances
shifting to the eastern half of the area for Sunday. A low chance for
strong to severe storms continues this day. Storms this weekend may
also produce heavy rain at times leading to isolated flooding,
especially if falling over locations that have seen rainfall in
previous days.

Highs will range from the upper 70s and low 80s today across the
northeastern half of the area to the mid to upper 80s over the Rio
Grande Plains and along the Rio Grande. Cloud cover will thicken and
lower overnight with lows in the mid 60s to low 70s. Sunday may be a
few degrees warmer than today in some locations, with highs
generally in the 80s to mid 90s.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 215 AM CDT Sat May 11 2024

Ongoing showers and perhaps a few thunderstorms will be possible
Sunday night as an 500mb low over central Kansas passes to our north.
On Monday, a shortwave looks to round the base of the passing 500mb
low, resulting in another round of showers and storms by the
afternoon. Additionally, a weak frontal boundary should slide through
our region Monday afternoon and evening, providing a surface focus
for convection to develop along as it moves south and east. The
latest global guidance from the GFS/ECMWF hints at a threat for some
strong to severe storms Monday afternoon and evening as this front
moves through. Deep layer shear of 40-50 kts, and MLCAPE of 1500-2000
J/kg shouldn`t be hard to come by, by MLCIN may be a bit on the high
side, so a cap may be in place. With a boundary to focus convection
on and a shortwave disturbance to work with, a threat for large hail
and damaging wind may materialize Monday afternoon and evening over
the Hill Country, I-35 Corridor, and the Coastal Plains. SPC places
the I-35 Corridor and points eastward within a level 2 of 5 risk for
severe storms Monday afternoon and evening.

After the front has passed, we may see a brief break from the
humidity on Tuesday as afternoon dewpoints fall into the 60s rather
than 70s like we will experience Monday afternoon/evening ahead of
the frontal boundary. Afternoon highs may be a tad cooler, but the
main difference will be lower humidity. Highs should top out in the
upper 80s to mid 90s from east to west. Shortwave ridging at the
500mb level should result in a dry forecast Tuesday.

On Wednesday, yet another round of showers and thunderstorms looks
like a good bet, particularly out west over the Rio Grande Plains and
Southern Edwards Plateau. A broad 500mb trough over the Four Corners
will eject out over the Southern Plains states, resulting in strong
southerly surface flow and increasing instability and deep layer
shear. Storms look to develop over the western zones and spread
eastward by Wednesday night into early Thursday before clearing the
region. For now, there is no extended period severe outlook from SPC,
but the risk exists at this distance as model guidance has come into
better agreement over the last couple days.

Once storms exit the region Thursday morning, we should see hot and
dry weather return as 500mb ridging attempts to build in from
northern Mexico in the 6-8 day time frame.

&&

.AVIATION...
(18Z TAFS)
Issued at 1217 PM CDT Sat May 11 2024

VFR flight conditions are to prevail into the early evening before
conditions deteriorate. Shower and storm chances will develop later
this evening and should peak overnight into Sunday morning. These
then decline into and through Sunday afternoon as majority of rain
and storm advances north and east. Into the overnight and early
Sunday morning period, have elected to go with prevailing -SHRA and
some PROB30 groups with -TSRA. Uncertainty remains on timing and
placement of activity, and this will continue to be refined during
the period. In addition to the rain shower and convective potential,
MVFR to IFR ceilings will be expected to develop. Some visibility
reductions also will be possible with any showers or storms. Later
Sunday afternoon, expect for the 30 hr TAF sites to improve back
towards VFR levels. The winds will shift from easterly to more
southeasterly with time through the period as well.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              68  83  73  87 /  40  50  20  40
Austin Bergstrom Intl Airport  68  83  72  86 /  40  50  20  40
New Braunfels Muni Airport     70  87  73  89 /  40  30  20  40
Burnet Muni Airport            67  81  70  86 /  40  60  20  20
Del Rio Intl Airport           73  94  73 100 /  40  20  20  10
Georgetown Muni Airport        68  80  72  85 /  40  60  20  30
Hondo Muni Airport             70  88  73  92 /  40  20  20  30
San Marcos Muni Airport        68  84  73  87 /  40  40  20  40
La Grange - Fayette Regional   70  83  74  85 /  40  60  30  50
San Antonio Intl Airport       70  87  74  90 /  40  30  10  40
Stinson Muni Airport           71  88  75  90 /  40  30  10  40

&&

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

$$

Short-Term...Brady
Long-Term...MMM
Aviation...Brady