922
FXUS64 KEWX 170543
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1243 AM CDT Fri May 17 2024

...New AVIATION...

.UPDATE...
Issued at 807 PM CDT Thu May 16 2024

With the strong cool outflows from the late afternoon squall line, we
were due for a foreast update. Low temps with a early start to
cooling will get a nudge downward. A severe hailstorm over Menard
County is barreling toward Llano County and could present a severe
risk for the next hour. We think the storm should weaken some as the
cool outflow winds should reduce some of the lower level instability.
By the looks of it, there`s probably enough mid level instability to
hold it together long enough to bring at least some small hail into
the CWA. SPC Mesoanalysis depict another county worth of steep mid
level lapse rates downstream from the storm, but a significant drop
off in lapse rates once it reaches Llano County. Thus we are still
carrying low chance PoPs for the Austin metro area, but do not think
the threat for severe weather is anywhere near the levels it was
earlier. Nevertheless, there remains a Marginal Risk over most of the
area with a Slight Risk over West Central Texas extending south into
parts of our Edwards Plateau/Western Hill Country counties.

&&

.SHORT TERM...
(Tonight through Friday night)
Issued at 129 PM CDT Thu May 16 2024

Showers and even a few thunderstorms are beginning to increase in
coverage across the eastern half of the CWA, especially across the
northern Hill Country in advance of a developing MCS. With this MCS,
damaging wind gusts and heavy rainfall will be the primary threats,
though isolated instances of large hail will be possible with any
discrete storms that develop. This activity will continue to increase
in coverage and move east across the Severe Thunderstorm Watch area
into the evening hours. The current watch is in effect through 22Z,
though a local extension in time may be needed if storms look to
linger beyond then. South of the watch area, more isolated convection
is possible through the evening. While this activity could be severe
as well, coverage will likely be limited due to the widespread cloud
cover that has been in place all day.

Confidence in the placement of convection, if any, decreases
substantially overnight, though isolated storms will remain possible
across generally the same areas as this afternoon. Chances for
storms look to increase again around and after sunrise tomorrow
morning as a second subtle upper level disturbance moves out of
northern Mexico, but CAMs keep the majority of this activity south
of our CWA border. Any activity that sneaks north of this border
could be strong to severe, and therefore a level 1/5 risk is in
place across the southern half of our area. As we move into Friday
afternoon, a secondary area to watch will be near Val Verde County
as isolated storms may develop across west Texas/northern Mexico and
push east into the evening. A weak front will have moved south of
this area by tomorrow afternoon, which leads to lower confidence in
convection developing at all, but if it does it will be high based
in nature and carry an isolated hail/wind threat. In the absence of
these storms, conditions will be dry and mostly clear for Friday
evening/night.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 129 PM CDT Thu May 16 2024

Hot, above average, temperatures prevail over South-Central Texas
through this weekend into next week as mid-level ridging across
Mexico strengthens. Additionally, majority of the period will
include light to moderate south-southeasterly winds off the Gulf
with surface high pressure displaced to the east. This yields to
higher humidity levels, especially across our southern and eastern
most zones. The heat indices, especially into early to middle of
next week, will climb into the 103 to 108 degree range for many
areas. A drier heat is expected out west along the Rio Grande but
afternoon high temperatures will easily climb above 100 degrees
across those areas. Rain chances remain minimal through at least
early next week. An approaching shortwave out of the west could
allow for slight rain/storm chances to re-enter the forecast into
the Hill Country next Wednesday and Thursday afternoon.

&&

.AVIATION...
(06Z TAFS)
Issued at 1243 AM CDT Fri May 17 2024

Isolated TSRA will track near SAT over the next hour, and gradually
weaken. Additional SHRA and isolated TSRA development is possible
overnight southeast of SAT. Otherwise, MVFR ceilings overnight for
most locations, but the Rio Grande. Some pockets of IFR ceilings and
IFR to MVFR visibilities in BR are possible around sunrise, mainly
near and north of a T82-BAZ-3T5 line, including AUS. VFR conditions
developing Friday afternoon. Isolated to scattered TSRA activity is
indicated by several CAMs to develop in NW Mexico and along the Rio
Grande Friday afternoon, tracking east near DRT late afternoon and
early evening and potentially into the Hill Country and lesser
confidence near the I-35 corridor. For now we have included a PROB30
TSRA group at just DRT for this.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              87  67  92  71 /  10  10   0   0
Austin Bergstrom Intl Airport  86  66  92  70 /  10  10   0   0
New Braunfels Muni Airport     88  67  94  70 /  10  10   0   0
Burnet Muni Airport            85  64  91  70 /   0  10   0   0
Del Rio Intl Airport           99  71 105  77 /  20  20   0   0
Georgetown Muni Airport        85  66  90  70 /  10  10   0   0
Hondo Muni Airport             94  66  97  70 /  10  20   0   0
San Marcos Muni Airport        87  65  93  69 /  10  10   0   0
La Grange - Fayette Regional   84  68  90  70 /  20  10   0   0
San Antonio Intl Airport       90  68  94  72 /  10  10   0   0
Stinson Muni Airport           91  69  95  72 /  10  10   0   0

&&

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

&&

$$

Short-Term...Gale
Long-Term...Brady
Aviation...76