611
FXUS64 KEWX 091730
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1230 PM CDT Sun Jun 9 2024

...New AVIATION...

.SHORT TERM...
(Today through Monday)
Issued at 250 AM CDT Sun Jun 9 2024

Upper ridge amplification over the SW CONUS has become locally
weakened over TX over the weekend as the H7-H5 ridge center drifted
east to the coast of Louisiana while an upper low has been funneling
Pacific Moisture into much of Mexico and parts of West TX. To the
north a light NW flow continues to promote high plains convection
with a few clusters drifting as far south as the lower TX Panhandle.
Still the high pressure grasp is tight enough to maintain stability
over Central and South TX for today, but some weakening in stability
could begin as early as 00Z Monday with moisture levels expected to
increase at mid levels from the west and north and low level
moisture improving from a pool of deeper moisture feeding from Deep
South TX. Temperatures may not respond as much to this moisture
influx, and we are not expecting much better cloud cover in the
periods prior to 21Z. However, the late day RH values leveling off
could take a toll on high temps and hold the heat index below
advisory levels at the same time. Needless to say, it will still be
muggy.

At 00Z, the PWat values take a jump towards values that might be
able to take advantage of the slightly above normal heat.
Instability and a weak tropical tap from the west is depicted to
fire off some isolated convection from the Edwards Plateau into
Mexico for this evening. This convection doesn`t progress much as
the steering flow should be light. However, while this is occurring,
northerly mid level flow and a cold front advances south into NW TX
and promotes scattered convection of NW and North Central TX
overnight. We think there will be still low coverage of convection
to impact our forecast area late tonight, but the daytime setup
should be a lot better for diurnal instability for Monday. Outflow
boundaries and competing influences from upper support features will
make this a low confidence forecast for timing and location for rain
chances, but most areas should at least see an uptick, and the extra
clouds, moisture, and outflows should translate to further
moderations to the daytime Max T for Monday.

As with most storm activity that can occur in early to mid June,
there`s always a low end chance a storm could become severe, and a
level 1 of 5 risk for severe weather will cover various parts of our
northern and western counties today through Monday.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 250 AM CDT Sun Jun 9 2024

The latest round of medium range model guidance has trended slower
and a little stronger with regards to an upper system dropping
southward out of the Texas Panhandle late Monday. As this system
slows and continues to drop southeastward into central and east Texas
through Wednesday, some precipitation chances can be expected given
active northwest flow aloft. Northwest flow aloft patterns tend to
favor the Hill Country westward into the southern Edwards Plateau and
the latest models do tend to place the higher rain chances in these
areas through mid-week. Timing of shortwave activity that will help
trigger convection will be tricky. For now, we may need to monitor
the late Tuesday into early Wednesday period as the operational GFS
and NAM show some higher precipitation totals across the region. For
now, we will keep chances capped around 30%, but could need to go
higher pending later model runs.

Temperatures are still expected to slowly trend upward through mid-
week, with highs in the 90s to near 103 degrees along with lows
mainly in the 70s.

The remnants of the above mentioned upper low drop into the
northwestern Gulf of Mexico on Thursday as the mid and upper level
subtropical ridge builds over northern Mexico into the desert
southwest. With this pattern, temperatures will remain steady or
slowly rise through next week along with most areas remaining dry. A
few spots mainly south of I-10/Highway 90 will need to be monitored
for a possible Heat Advisory on Thursday and possibly Friday.

&&

.AVIATION...
(18Z TAFS)
Issued at 1229 PM CDT Sun Jun 9 2024

VFR conditions have returned for all sites, although a cloud deck
just above 3kft lingers near DRT for the next hour or two.
Southeasterly flow may be breezy at times this afternoon and evening
with gusts to around 20 knots, with light winds returning across
South Central Texas overnight. There is a signal for patchy MVFR
ceilings to return mainly to SAT/SSF, but recent trends suggest it
may stay northwest of terminals. Brief MVFR conditions may also be
seen at DRT around sunrise.

Chances for showers or thunderstorms is mainly limited to the
western half of the area overnight into Monday morning as a complex
forms in northwest Texas before moving towards the south/southeast
into the area. Used a PROB30 group at DRT to highlight this
potential. While it is possible SAT/SSF could see some activity,
confidence is too low to add any mention at this time. Better chances
for thunderstorms at I-35 sites may be seen Monday afternoon with
isolated to scattered thunderstorm development as a front moves south
towards South Central Texas.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              75  94  74  94 /  10  20  10  10
Austin Bergstrom Intl Airport  75  94  74  94 /  10  20  10  10
New Braunfels Muni Airport     75  95  74  96 /  10  20  10  10
Burnet Muni Airport            74  91  72  91 /  10  30  10  10
Del Rio Intl Airport           80  99  80 101 /  20  30  20  10
Georgetown Muni Airport        74  91  73  92 /  10  20  10  10
Hondo Muni Airport             76  95  74  97 /  20  20  10  10
San Marcos Muni Airport        74  94  73  94 /  10  20  10  10
La Grange - Fayette Regional   75  93  74  92 /  10  20  10  10
San Antonio Intl Airport       77  95  76  96 /  10  20  10  10
Stinson Muni Airport           78  96  76  98 /  10  20  10  10

&&

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

$$

Short-Term...18
Long-Term...Platt
Aviation...27