671
FXUS64 KEWX 090118
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
818 PM CDT Wed May 8 2024

...New UPDATE...

.UPDATE...
Issued at 818 PM CDT Wed May 8 2024

The capping inversion proved just too hard to break to allow for deep
convection this afternoon into this evening. A couple of showers near
Lake Buchanan and a shower north of Fredericksburg fizzled out
earlier. A shower over Lampasas County will be of no impact to our
area. With the capping only getting stronger with sunset, no
additional development is expected. As a result, will cancel the
Tornado Watch and remove POPs for our northeastern areas for this
evening. Have re-established trends to the temperatures, dewpoints,
and winds for the remainder of tonight into early morning.

There remains a much better chance of showers and thunderstorms for
Thursday afternoon near the intersection of a dryline and cold front
over the Hill Country. Then, steering flow will take them across
I-35 corridor northeast of San Antonio to the US 77 corridor during
the late afternoon into evening when they will dissipate with loss of
heating. Forecast soundings show strong to extreme instability with
MLCAPE of 3,500+ J/kg and steep mid level lapse rates of 8.5 C/km,
and high 0-6 km shear of 50 KTs. A few strong to severe storms are
expected during the afternoon into early evening. Large, possibly
very large hail (2 to 3 inches) and damaging wind gusts up to 70 mph
are the main threats, however cannot rule out a tornado or two.

&&

.SHORT TERM...
(Tonight through Thursday night)
Issued at 145 PM CDT Wed May 8 2024

Low cloud cover continues across much of the eastern two-thirds of
the area with clearing out west. With the clearing out west Del Rio
is already at 93 degrees at 1 pm. For locations outside of the Rio
Grande Plains, temperatures are in the 80s. Highs later today will
range from the lower to middle 90s with 100-103 degrees temps out
west and this should be near record high values for Del Rio.

A weak boundary was seen on radar earlier today and has become
somewhat stationary in the Hill Country. As temperatures rise into
the 90s later today we could see an isolated storm develop near this
boundary across mainly the northern counties by 5 pm or so. Would
not expect the storms too last too long, and die off somewhat
quickly with the loss of day time heating. There is another
conditional threat of severe weather with this activity as the
environment is favorable for severe storms with large hail being the
main risk. Overall PoPs are low but will mention the threat of
isolated storms with a 10 PoP for the northern counties through 7
pm.

Most of the tonight period will be quiet with warm temperatures once
again. Lows will be back in the upper 60s to upper 70s. There will
also be additional low clouds and patchy fog across much of the
area. Another hot day is expected tomorrow with highs back in the
lower 90s to 105 degrees. Del Rio should fall just below record
values tomorrow. A weak boundary will approach the area by the early
afternoon hours and high-res and global guidance is consistent on
showing development of some scattered strong to severe storms for
areas mainly north of a Fredericksburg to New Braunfels to
Halletsville line. Large hail and damaging winds would be the main
threats with this activity. There is a level 3 out of 5 (enhanced)
risk of severe storms with this activity. Much of this activity will
be over by 9 pm with the remainder of the night period rain free.
Lows will be in the middle 60s to lower 70s.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 145 PM CDT Wed May 8 2024

Post-frontal temperatures cool off from the ongoing well above
average conditions from Friday into this upcoming weekend with
northeasterly to easterly surface winds. A cutoff low across the
Desert Southwest will help to maintain a southwesterly flow aloft
over the region. An occasional ripple of some weak upper level
energy may be embedded within the flow at times. This may help to
spark some convection across the terrain of Mexico that could
attempt to move into our western zones, mainly close to the Rio
Grande, Friday evening and again Saturday evening. Saturday will
have the slightly better odds compared to Friday for activity
advancing past the river. Rain and storm chances become highest
Sunday through Monday, including across interior portions of the
region, as the upper level low gets closer and supplies better
forcing to the region. While temperatures will help to limit
instability compared to recent days, it does remain sufficient and
with enough shear where some strong storms could be possible.
Additionally, locally heavy rain may be possible, especially for
locations that see multiple or training storms. Medium range
guidance does indicate greater uncertainty given differences on
timing and location of the upper level low.

A warmer and more humid southerly flow regime returns by early to
middle of next week. Rain and storm chances will be expected to
lower behind the exiting upper level low but is not completely
eliminated. Low to very low end chances become more conditional
pending the capping inversion with any minor forcing as higher
instability will again pool over the region with the warmer
afternoon temperatures.

&&

.AVIATION...
(00Z TAFS)
Issued at 636 PM CDT Wed May 8 2024

Over most areas, including the I-35 sites, VFR skies early this
evening lower to MVFR CIGs by late this evening, then IFR to LIFR
overnight with reductions to VSBY due to BR/HZ. CIGs rise to MVFR
late Thursday morning and VFR in the afternoon. Light southeasterly
winds back to easterly by Thursday morning, then northeasterly in the
afternoon into evening. Meanwhile, out west, including KDRT, VFR
skies prevail, except a brief MVFR CIG early Thursday morning. Light
easterly winds shift to northwesterly at 7 to 14 KTs on Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              74  92  69  82 /   0  30  10  10
Austin Bergstrom Intl Airport  74  92  68  82 /  10  30  10  10
New Braunfels Muni Airport     74  94  70  84 /   0  20  10  10
Burnet Muni Airport            73  88  66  79 /   0  40  10  10
Del Rio Intl Airport           75 105  72  89 /   0   0  10  30
Georgetown Muni Airport        73  90  66  80 /   0  40  20  10
Hondo Muni Airport             73 100  71  86 /   0   0   0  10
San Marcos Muni Airport        74  93  69  83 /   0  20  10  10
La Grange - Fayette Regional   76  90  71  84 /   0  20  10  10
San Antonio Intl Airport       74  98  71  84 /   0  10  10  10
Stinson Muni Airport           75  99  73  85 /   0  10   0  10

&&

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

$$

Short-Term...04
Long-Term...Brady
Aviation...04