710
FXUS64 KEWX 051143
AFDEWX

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

...New AVIATION...

.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...
(12Z TAFS)
Issued at 634 AM CDT Sun May 5 2024

Surface obs show a bit more stability than is baked into the model
solutions for the early periods thanks to a slightly over-achieving
outflow from the overnight convection. VFR skies should start off the
day for a good couple hours as winds remain out of the east and north
over most areas. Less clearing will occur at DRT early on as the
outflows have pushed a lot of the low level moisture and instability
up against the border. Light shower activity around DRT could
escalate into storms early in the day as models have been somewhat
consistent on a secondary shortwave response combined with daytime
heating. The latest HRRR also generates a return flow of convection
into I-35 more from the east, instead of the south and overhead
above SAT as suggested by earlier runs. Thus the AUS return to
instability could happen at roughly the same time as the SAT/SSF
areas. Expected coverage of storms is low, but shower coverage is
probably going to be closer to 50 percent. This is to hint at storm
intensities possibly not being as strong due to the cooling outflow,
but the later day period storms could become stronger as previously
anticipated. Some stable air expected to settle in tonight, so the
hint is out there that we could drop into some LIFR/VLIFR conditions
from fog and low clouds later tonight.

&&

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

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 1 PM CDT this afternoon for Burnet-Lee-Llano-
Williamson.

&&

$$

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