123
FXUS64 KEWX 170118
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
818 PM CDT Thu May 16 2024

...New UPDATE...

.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...
(00Z TAFS)
Issued at 722 PM CDT Thu May 16 2024

Convective trends are down to being negligible for the night at all
four TAF sites. Some gusty outflows should settle down over the I-35
corridor in the next hour. New instability could show up after the
modified air mixes out late in the TAF period but only isolated
coverage is suggested. A large area of MVFR cigs has built over the
I-35 corridor, but it could mix out to VFR for a few hours before
dropping back to MVFR late this evening and possibly IFR after
midnight. CIG forecasts could be a bit too pessimistic, but will wait
and take a look at the 00Z forecasts before adjusting the latter
periods if necessary.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              64  87  67  92 /  30  10  10   0
Austin Bergstrom Intl Airport  65  86  66  92 /  40  10  10   0
New Braunfels Muni Airport     65  88  67  94 /  30  10  10   0
Burnet Muni Airport            62  85  64  91 /  40   0  10   0
Del Rio Intl Airport           70  99  71 105 /  10  20  20   0
Georgetown Muni Airport        62  85  66  90 /  30  10  10   0
Hondo Muni Airport             65  94  66  97 /  20  10  20   0
San Marcos Muni Airport        64  87  65  93 /  30  10  10   0
La Grange - Fayette Regional   66  84  68  90 /  60  20  10   0
San Antonio Intl Airport       66  90  68  94 /  20  10  10   0
Stinson Muni Airport           67  91  69  95 /  20  10  10   0

&&

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

$$

Short-Term...18
Long-Term...04
Aviation...18