271
FXUS64 KEWX 120801
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
301 AM CDT Fri Jul 12 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Today through Saturday)
Issued at 238 AM CDT Fri Jul 12 2024

For the past few days, air mass showers and storms have been forming
over mainly the southern half of South Central TX, as an inverted
mid level trough was positioned from Northern Mexico into Central TX
and an upper level trough axis extended SW-NE across West and NW TX.
Thursday`s convection had positioned most of the convective activity
a bit farther south, with very little activity north of US Hwy 90.
This can be well correlated with where the NAM/GFS PWat initiation
displayed an E-W gradient with a near or greater than 2 inch
threshold over where convection was more active.

For the short term, there will be a slow N/NW lift of the inverted
trough axis, leading to the pockets of near 2 inch or higher PWat
values pushing farther inland into parts of the Hill Country and
Central Texas later today into Saturday. Thus we should see a more
widespread coverage of 20-40 percent PoP values for South Central
Texas with best coverage occurring in the daytime and early evening
hours. This, in addition to higher amounts of fair weather cumulus
and mid level clouds should also make for milder temperatures today
and Saturday.

As with much of the activity seen this week, there should be a few
lucky locations to get a healthy 1 to 2 inch downpour, and other
areas to see gusty winds over 40 mph.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 238 AM CDT Fri Jul 12 2024

A broad upper low is expected to remain over northern Mexico through
the remainder of this weekend. Some weak lift with this feature will
keep some low rain chances in the forecast for the Rio Grande plains
through Sunday. Elsewhere, we will keep the forecast dry, but may
need to keep an eye on the coastal plains for the possibility of some
isolated convection. Temperatures should remain near normal, with
readings a few degrees below normal over the Rio Grande plains given
increased cloud cover and precipitation chances.

As we head into the early and middle portion of next week, the upper
low mentioned above will weaken, with another inverted trough/weak
low expected to develop over southwest Texas. A few of the medium
range models even show a portion of this system may stretch farther
east into portions of northeast Texas. For now, we will keep rain
chances confined mainly to the Rio Grande plains and southern Edwards
Plateau, with a dry forecast elsewhere. Temperatures will manage to
warm to at or just above normal for most of the region. At this
point, it looks like we should stay below any Heat Advisory levels.
Toward the end of the forecast period, most of the medium range
models show a weak cold front may manage to slip southward into the
northern portions of Texas. For now it looks like the front will
mainly stay to our north, but will continue to monitor as some low
rain chances might be needed if the boundary slips a little farther
south.

&&

.AVIATION...
(06Z TAFS)
Issued at 1241 AM CDT Fri Jul 12 2024

VFR skies should predominate the TAF periods over the next 24 to 30
hours, but a flux of higher moisture content from the south could
bring a few more pockets of MVFR ceilings into mainly the San Antonio
area close to daybreak. The low cigs shouldn`t last more than just a
few hours. Increasing PWat values from the south into the Highway 90
corridor could give SSF/SAT an increasing chance of convection as
early as noon. We show the longest period of Prob30 groups here, and
a need to go TEMPO may take shape if we see the radar echoes lighting
up to the south by 11Z. Isolated convection is possible a couple
hours later at DRT/AUS and a smaller time window of Prob30 convection
is offered at those sites. Main reason to include this period is to
account for outflow winds as the core of brief heavy downpours will
be much harder to pin down. By around 02Z most of the convection
should wane, at least around the TAF locations. Non-outflow winds
from the E/SE could pick up to near 10 knots in the mid afternoon at
any of the TAF sites, but most of the night and morning winds should
remain around 8 knots or lower with variable directions at times.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              96  76  95  77 /  20  10  20   0
Austin Bergstrom Intl Airport  94  75  94  76 /  20  10  20   0
New Braunfels Muni Airport     94  76  93  76 /  30  10  20   0
Burnet Muni Airport            95  74  93  75 /  10  10  20   0
Del Rio Intl Airport           95  78  92  78 /  30  10  40  20
Georgetown Muni Airport        94  75  93  76 /  20  10  20   0
Hondo Muni Airport             91  75  90  75 /  30  10  30  10
San Marcos Muni Airport        93  73  93  75 /  20  10  20   0
La Grange - Fayette Regional   92  75  91  74 /  30  10  30   0
San Antonio Intl Airport       93  76  93  77 /  30  10  30  10
Stinson Muni Airport           93  76  93  77 /  30  10  30   0

&&

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

$$

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