Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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FXUS64 KEWX 071914

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
214 PM CDT Wed Jun 7 2023


(Tonight through Thursday night)
Issued at 213 PM CDT Wed Jun 7 2023

The H5 ridge axis that`s been hanging out to our west did shift
slightly eastward over the past 12-24 hours and is now stretched
across the Big bend and far eastern NM. Thus, weak NW flow aloft
continues over a moist boundary layer. Sfc obs show temps already in
the 80s w/ dew points in the 60s to lower 70. Areas near Austin and
south and west of San Antonio will see highs in the low to mid 90s.

A broad cumulus field developed during the day, with isolated
convection developing late this morning over the Hill Country. These
pulse-type storms have been capable of producing brief 0.5" hail and
winds up to 30-40 mph, as well as a quick 0.5-1.5" of rain. Like
yesterday, this activity will increase slightly in coverage this
afternoon before diminishing quickly in the evening with the loss of
daytime heating. However, our attention will then turn to the west
for the overnight period.

There isn`t much more than a diffuse dryline today and and little in
the way of direct forcing, but daytime heating and venting in the
left exit region of the H3 jet should allow a cluster of storms to
develop across the Trans-Pecos and Big Bend under the weak H5 ridge.
Most guidance indicates a decent chance for this activity to grow
upscale before moving into our far western areas. There is a low end
risk for some large hail and damaging winds in Val Verde County
mainly after 8pm, with storms weakening as they move ESE through the
night. An isolated 2"/hr rain total is possible, with very minor
flash flooding impacts should that occur, but chances are relatively
low that we`ll see too many issues. Storms are likely to end before
reaching the US-281 corridor late tonight.

These storms will help to flatten the ridge axis temporarily
overnight, but it will amplify again on Thursday over approximately
the same location before shifting slightly east late. Even warmer
temperatures are likely to reach the 90s in most locations,
approaching 100 near FTN. CAMs keep us in a similar pattern as the
past few days, but with the upper jet translating slightly further
east we may have some additional upper divergence to assist storm
development on Thursday as remnant outflow boundaries and perhaps an
MCV from convection in the panhandle tonight drift southeastward
into the region. Deep layer shear is marginal but should increase to
near 30 knots in the afternoon, and there is likely to be a solid 2-
3kJ/kg CAPE to work with, except on the off chance tonight`s storms
linger late and make it further east than anticipated. Thus, another
Marginal Risk for severe weather is outlooked for most areas except
along the Rio Grande closer to the ridge axis. The best chances for
any isolated large hail or damaging winds will be from noon to 7pm
along and east of US-281. Again, a quick 1-2" of rain is possible in
some areas, though others will see nothing at all. Look for storm
coverage to again diminish through the evening hours, with overnight
lows in the upper 60s and lower 70s.


(Friday through Wednesday)
Issued at 213 PM CDT Wed Jun 7 2023

Synopsis: Ridging will continue to remain prominent over central
portions of the continent through the long term period. This will
translate to steadily warming surface temperatures, and overall low
chances for appreciable precipitation. Isolated storms can`t be
entirely ruled out on Friday and Saturday evenings over the far
north as shortwave energy ejects into north-central Texas from New
Mexico. Widespread precipitation is not expected. Subtropical high
pressure is forecast to develop over northern Mexico early next
week. With the northern periphery of the feature extending into the
Southern Plains, high temperatures will soar to their warmest
readings of the year thus far.

Friday & Saturday: While mentionable PoPs are present across
northwestern Val Verde County only in this update, the potential for
isolated to scattered showers and thunderstorms will exist
regionally as a broad area of height falls pivots east out of New
Mexico. Most guidance shows scattered convective development across
the Lower Trans Pecos and Edwards Plateau on Friday evening, with
some activity potentially sneaking into portions of Val Verde County
before it pushes northeast and away from our CWA. Most progs keep a
more organized convective complex to our northeast on Saturday,
although multiple consecutive runs of the deterministic GFS suggest
the potential for isolated thunderstorm development along the
Serranias del Burro Mountains during the late afternoon and early
evening hours. Am inclined to treat this solution as an outlier for
the time being, though 10% PoPs with no weather mentions have been
inserted along the Rio Grande to account for this low-end potential.
Will continue to monitor convective trends during this portion of
the period accordingly, as an isolated strong storm could be
possible in any activity that manages to develop given the
combination of ample instability and modest shear that will be in

Remainder Of The Period: Temperatures will climb to their highest
readings of the year so far as a closed area of subtropical high
pressure forms over Mexico and nudges north toward the Southern
Plains. Ensemble situational awareness tables from the NAEFS show
95th+ percentile 850 mb temperatures becoming established by the
Monday-Tuesday timeframe and persisting through the end of the long
term. Preliminary PM forecast soundings depict deep, nearly dry-
adiabatic boundary layers extending up and through 850 mb across the
majority of the region, implying that said warmth should have no
issues mixing down to the surface during each afternoon period
Monday through Wednesday. Expect that many locations outside of Hill
Country will see their first 100 degree highs of the year, if they
haven`t already. While still several days away, now is the time to
begin preparing for potentially very hot conditions next week. Be
sure to drink plenty of water, in addition to wearing light-colored
and loose-fitting clothing if you plan to be outdoors for prolonged
periods of time during this portion of the long term period.


(18Z TAFS)
Issued at 1200 PM CDT Wed Jun 7 2023

Isolated TSRA has begun to develop over the Hill Country early this
afternoon within a broader cumulus field. Storm coverage is expected
to be similar to or slightly less than yesterday, and terminal
impacts are possible but no guarantee this afternoon. For now, will
hold onto VCTS at all I-35 terminals, however may need to amend w/
TEMPO if slow moving storms drift towards the terminals. Light and
variable winds are forecast through tonight, though there should be a
more consistent SSE direction at KDRT. There is a slightly better
chance for storms to impact KDRT between 04-07Z, with a temporary
wind shift to the NW possible as these storms approach. VFR
conditions will prevail through the period at all sites otherwise.


Austin Camp Mabry              71  94  71  98 /  10  30  20   0
Austin Bergstrom Intl Airport  68  93  69  96 /  10  30  20   0
New Braunfels Muni Airport     69  93  69  96 /  10  30  20   0
Burnet Muni Airport            69  91  69  96 /  10  30  10   0
Del Rio Intl Airport           71  97  74 102 /  30   0   0   0
Georgetown Muni Airport        69  93  69  97 /  10  30  10   0
Hondo Muni Airport             69  94  69  97 /  10  20   0   0
San Marcos Muni Airport        68  93  69  96 /  10  30  20   0
La Grange - Fayette Regional   70  91  70  94 /   0  20  20   0
San Antonio Intl Airport       70  93  71  96 /  10  30  20   0
Stinson Muni Airport           71  94  71  97 /  10  30  20   0




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