516
FXUS64 KEWX 051815
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
115 PM CDT Sun May 5 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE FOR SEVERE THUNDERSTORM WATCH 186
... Issued at 112 PM CDT Sun May 5 2024

We have issued a Severe Thunderstorm Watch for the area along and
south of Hwy90/I-10. Storm strength has increased over the past hour
or two and the environment is ripe for this to continue into the
early evening. Large hail and damaging wind gusts are the most likely
threats with tornadoes also possible.

&&

.SHORT TERM...
(Today through Monday)
Issued at 433 AM CDT Sun May 5 2024

Current radar data shows a line of convection in place from the
western Hill Country into portions of the I-35 corridor near Austin.
Concerns for severe storms will be on the decrease through the early
morning hours as convective inhibition slowly builds. Severe
Thunderstorm Watch #185 was allowed to expire at 2 AM CDT. While the
threat for severe storms has temporarily eased, we are seeing some
healthy rainfall rates embedded within this line with instantaneous
amounts on the order of 4-5" per hour. Luckily, this line of
convection is steadily moving eastward and will continue to do so
through the pre-dawn hours. We are also noting some new convective
development over the lower Trans Pecos region as the leading edge of
a frontal boundary interacts with an outflow boundary from earlier
convection.

Recent runs of the HRRR model generally capture what is unfolding on
radar and the weakening of this line is expected to continue through
this morning. With precipitation still ongoing across areas covered
by the Flood Watch, Burnet, Lee, Llano and Williamson counties, the
Watch will remain in effect until 1 PM CDT. We could still see some 1
to 2 inch amounts with a few spots up to 3 inches. Any moderate to
heavy rain falling over these areas will result in quick runoff and
continue to pose a flood threat. For the late morning and afternoon
hours, hi-res models generally agree in showing renewed convective
development along an outflow boundary. Any breaks in the cloud cover
will help destabilize the atmosphere and with adequate shear, a few
strong to severe thunderstorms are possible, especially along and
south of a Rocksprings to San Marcos line. Large hail and damaging
winds will be the main severe weather concerns. Rain chances should
begin to decrease fairly quickly with the loss of daytime heating.
Wet ground tonight along with southerly flow in the low-levels will
likely lead to fog development late tonight into Monday morning.
Highs on Monday will range from the lower 80s in the Hill Country to
the mid and upper 90s along the Rio Grande. We will keep a low chance
for some afternoon convection across the Hill Country, but overall
confidence is low at this time.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 433 AM CDT Sun May 5 2024

A broad area of mid and upper level low pressure remains intact
across the central and high plains states through the middle of the
week. Farther south into the southern plains states, west-
southwesterly flow will persist as the low-level thermal ridge slowly
strengthens. Four our region, this will bring about a warming trend
for Tuesday through Thursday, with highs in the 90s for most areas.
The exception will be out west along the Rio Grande where some highs
on Wednesday and Thursday will warm into the 100 to 105 degree range.
These higher temperatures will likely be reached as the dryline is
able to mix eastward aided by 700mb westerly winds in the 20-30kt
range. As we head into the latter part of the upcoming week, the
upper air pattern begins to change as the medium range models show a
Rex block pattern taking shape over the western CONUS with a broad
trough farther east into the Great Lakes and upper Midwest. This
should allow a cold front to drop southward through the plains states
and eventually into south central Texas on Friday. Some notable
cooling will accompany the front as highs on Friday and Saturday ease
back into the upper 70s for areas generally along and north of I-10.
Elsewhere, highs will be mostly in the 80s, except near 90 along the
Rio Grande on Friday. We will keep a low chance for showers and
thunderstorms in the forecast for most areas on Friday and Saturday.

&&

.AVIATION...
(18Z TAFS)
Issued at 1231 PM CDT Sun May 5 2024

Slow moving showers and thunderstorms have formed across South
Central Texas, first impacting SAT/SSF for the start of the period
with thunderstorms possible at AUS around 19-23Z. Ceilings will
range from MVFR to VFR through the afternoon at all sites. Storm
activity should diminish early this evening with low MVFR/IFR
ceilings expected to return across the entire area tonight into
Monday morning. Fog may also be possible with wet grounds and light
wind, but ceilings my limit any dense fog formation. VFR conditions
return Monday afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              71  86  72  91 /  20  10  10   0
Austin Bergstrom Intl Airport  69  86  72  91 /  20  10  10   0
New Braunfels Muni Airport     71  88  72  93 /  20  10   0   0
Burnet Muni Airport            69  84  70  90 /  20  20  10   0
Del Rio Intl Airport           74  99  74 100 /  10  10   0   0
Georgetown Muni Airport        68  85  71  89 /  20  20  10   0
Hondo Muni Airport             70  88  70  94 /  20  20   0   0
San Marcos Muni Airport        69  87  71  92 /  20  10  10   0
La Grange - Fayette Regional   72  86  74  90 /  20  10   0   0
San Antonio Intl Airport       71  87  72  92 /  20  10   0   0
Stinson Muni Airport           72  88  73  94 /  20  10   0   0

&&

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

$$

Short-Term...Platt
Long-Term...18
Aviation...27
Meso Update...05