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

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FXUS64 KEWX 091122
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
622 AM CDT Sun May 9 2021

.AVIATION...
MVFR ceilings have held up all night and will continue into later
this morning. An approaching cold front will cause some showers and
thunderstorms in the Austin Area and for now have covered with VCTS
as there is little certainty that these storms will impact the
terminal. MVFR ceilings return tonight with easterly winds.

&&

.PREV DISCUSSION... /ISSUED 303 AM CDT Sun May 9 2021/

SHORT TERM (Today through Monday)...
Warm temperatures today with highs in the 90s and up to 103 along
the Rio Grande Plains. The dryline tomorrow will march from west
eastward while an approaching cold front marches south. Chances for
showers and thunderstorms will more likely be along the leading edge
of the front. Moderate CAPE of up to 2500 J/kg exists with a capping
inversion present. Timing is near enough to max heating that will
help destabilize ahead of the front forcing. The more likely area to
see strong to severe storms will be in the northeastern counties, or
to be more specific, a line from Llano to Fayette. As of this AFD
writing, SPC has this area highlighted as a marginal risk. Timing of
the front and accompanying storms will be late afternoon to early
evening.

Sunday night, after plenty of moist air was pumped into the area, a
warm and humid night with overnight lows in the 70s can be expected.
By Monday, a stalled cold front near the region and it`s associated
dryline extending southward could provide a focus area for more
strong to severe storms, though there still seems to be a lack of
significant forcing. With increasing moisture and instability, area
to watch is the western half of the CWA. Currently highlighted for
Slight risk by SPC for large hail, there still remains some
uncertainty.

LONG TERM (Monday Night through Saturday)...
Cold front drifts south out of our area into Southern Texas Monday
night. Moisture convergence and forcing along the front and moist
upslope flow on the Serranias del Burro will generate showers and
thunderstorms. Forecast soundings show MUCAPE of 2,000 to 4,000 J/kg,
effective bulk shear of 40 to 50 KTs, steep mid level lapse rates of
7 to 8.5 C/km, and long, generally straight hodographs indicating a
potential of strong to severe storms. Large, possibly very large hail
is the main threat with supercells. Damaging winds are also possible,
especially if storms can organize into clusters. Unseasonably high
moisture levels with PWs of 1.5 to 1.9 inches indicates a potential
for locally heavy rains. SPC has areas along and west of a Llano to
San Antonio to Dilley line in a slight risk of severe with the rest
of our area in a marginal risk.

Although the front will be south of our area Tuesday into Wednesday,
a weak mid level impulse will move over our area. With unseasonably
high PWs lingering, locally heavy rains will be the main threat and
may cause some flooding, especially in areas that have received heavy
rain during the last couple of weeks. MUCAPE of 1,000 to 1,500 J/kg
and lapse rates of 7 C/km in the mid levels suggests a threat of
large hail. Cold advection underneath cloudy skies and rain makes for
well below normal temperatures, possibly even cooler than currently
forecast.

As the mid level impulse moves away, forcing wanes and PWs decrease
later on Wednesday into Thursday. Showers and thunderstorms gradually
end from north to south. Fair weather is expected on Friday. Another
mid level impulse moves over our area next weekend bringing chances
of showers and thunderstorms on Saturday. A slow warming trend back
to near normal is expected.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              90  69  80  65  77 /  20  30  40  50  80
Austin Bergstrom Intl Airport  90  69  81  65  77 /  20  30  40  50  80
New Braunfels Muni Airport     93  71  85  67  79 /  20  20  30  50  70
Burnet Muni Airport            89  65  74  62  74 /  20  30  40  50  80
Del Rio Intl Airport          102  71  94  70  83 /   0  -   20  50  70
Georgetown Muni Airport        89  68  77  63  77 /  30  30  40  50  80
Hondo Muni Airport             96  72  90  68  82 /  10  -   30  50  70
San Marcos Muni Airport        91  70  84  65  78 /  20  30  30  50  70
La Grange - Fayette Regional   88  74  86  67  79 /  30  20  30  40  70
San Antonio Intl Airport       93  72  86  68  79 /  20  10  30  50  80
Stinson Muni Airport           95  74  89  69  81 /  20  -   20  50  70

&&

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

$$

Short-Term/Aviation...YBVP
Long-Term...04


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