546
FXUS64 KEWX 191131
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
631 AM CDT Wed Jun 19 2024

...New AVIATION...

.SHORT TERM...
(Today through Thursday)
Issued at 257 AM CDT Wed Jun 19 2024

Key Messages:

*Moderate to locally heavy rainfall will begin this morning and
continue into early Thursday.

*Confidence in the highest rainfall totals is seen across the far
southern portions of the area where the Flood Watch remains.

*Rain amounts have trended down overall.

*Isolated tornado threat remains across our southeastern-most
counties on Wednesday into Wednesday night.

Discussion:

All attention turns to Potential Tropical Cyclone One as it makes a
turn west towards northeastern Mexico later today, reaching the
coast late tonight or early Thursday. Early this morning, shower
activity is noted over the Gulf Coast expected to reach the coastal
plains near sunrise and I-35 corridor late morning. The Hill Country
will see rain activity in the afternoon with it reaching our western
reaches along the Rio Grande late afternoon or evening.

Precipitable water values are on the rise this morning with values
exceeding 2 inches over all of South Central Texas later today.
Limited instability is forecast as rainfall moves across the area
with only a few embedded thunderstorms expected. While the
environment will support efficient rain rates, the heaviest rain
totals have trended further south again with the latest model
guidance. WPC has followed this trend with their Excessive Rainfall
Outlook now only including a slight risk (level 2 of 4) for our
southernmost tier of counties and the moderate risk (level 3 of 4)
south of the CWA. Storm totals are now on the order of 0.25 to 1
inch north of I-10 with 1 to 3.5 inches in the southern half of the
CWA. Locally heavier amounts are possible in any location with any
bands of heavier precipitation. Due to the above, the Flood Watch
has been trimmed of the northern tier of counties including
Bexar/the San Antonio metro area.

East to northeasterly wind will increase this morning with gusty
wind remaining through tonight. Winds will gust anywhere from 20-35
mph through the evening and remain below Wind Advisory criteria. The
low tornado risk remains mainly across the coastal plains later
today and tonight with strong 0-1 km shear noted.

Activity will begin to taper off after sunset in the east but
continue over our western areas through Thursday morning. While some
may see a lull in activity overnight, shower and thunderstorm
chances increase again areawide Thursday afternoon with continued
high PWATS still in place. Thunderstorm activity may be scattered
with the potential for storms to produce heavy rain. WPC highlights
the western portions of the area in a slight risk (level 2 of 4) for
excessive rainfall for areas along the Rio Grande this day.

Temperatures during this period of wet weather will be cooler with
highs today topping out in the upper 70s and low 80s for a majority
of the area. In the far west where activity moves into late today,
some highs in the low 90s may still be seen. Slightly warmer for
Thursday but mostly cloudy skies will limit highs to the mid 80s to
low 90s across the area.

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 257 AM CDT Wed Jun 19 2024

The center of the Subtropical Ridge over the southeastern states on
Friday shifts to over Texas this weekend to over the southwestern
states/northern Mexico early next week. Another potential tropical
system indicated in the southwestern Gulf of Mexico on Friday should
move west into Mexico this weekend or early next week, though its
impacts on South Central Texas are uncertain. NHC currently (19/06Z)
has a 30 percent chance of tropical cyclone development. An
unseasonably moist airmass with PWs generally 1.4 to 2.1 inches
remains over South Central Texas through the period. While the Ridge
will provide some subsidence to inhibit convection, heating and the
potential tropical system should be able to overcome this for low
chances of mainly daytime showers and thunderstorms, especially over
our southern areas. Slightly below normal temperatures on Friday
warm to slightly above normal this weekend into next week. With the
increased soil moisture from the rain in the short-term, heat
indices may reach advisory levels on Sunday into next week along and
east of the I-35 corridor.

&&

.AVIATION...
(12Z TAFS)
Issued at 628 AM CDT Wed Jun 19 2024

Mainly MVFR ceilings over the area with some IFR conditions expected
over the coastal plains late morning. RA and SHRA activity
associated with a topical disturbance in the Gulf of Mexico is
moving into the coastal plains at the start of the period, expected
to impact I-35 sites near 16Z. Activity will continue west during the
day reaching the locations along Rio Grande late afternoon or
evening. DRT may see VFR conditions again late this morning into the
afternoon, but overall MVFR/IFR ceilings will be the normal today.
East to northeast wind will strengthen through the morning with gusts
from 20-30 knots forecast through the period. Late tonight into
Thursday morning, widespread IFR ceilings are forecast.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              82  76  90  74 /  70  50  30  10
Austin Bergstrom Intl Airport  81  75  90  73 /  70  50  30  10
New Braunfels Muni Airport     82  75  90  74 /  80  70  50  10
Burnet Muni Airport            82  74  88  73 /  50  50  30  10
Del Rio Intl Airport           93  77  90  77 /  40  80  80  60
Georgetown Muni Airport        81  74  89  72 /  60  40  30  10
Hondo Muni Airport             83  73  87  74 /  70  70  60  20
San Marcos Muni Airport        80  73  88  72 /  80  60  40  10
La Grange - Fayette Regional   80  76  89  74 /  80  40  40   0
San Antonio Intl Airport       82  75  88  75 /  80  70  50  20
Stinson Muni Airport           82  76  89  76 /  80  60  50  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Thursday afternoon for Atascosa-De Witt-Dimmit-
Frio-Gonzales-Karnes-Lavaca-Maverick-Wilson-Zavala.

&&

$$

Short-Term...27
Long-Term...04
Aviation...27