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

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FXUS64 KEWX 261748

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1248 PM CDT Tue May 26 2020

All sites VFR this afternoon and evening. Drier has mixed in from the
north and no significant changes are expected. Tomorrow evening,
storms return to the area that may impact the I-35 corridor at the
end of the TAF period.


PREV DISCUSSION... /ISSUED 400 AM CDT Tue May 26 2020/

SHORT TERM (Today through Wednesday)...
This morning starting out similar to yesterday with the main
grouping of strong storms gradually exiting our area to the south
and east. The cold front that helped to set off these storms is now
to our south while the parent 500mb trough axis now runs directly
N/S through our area. Another thunderstorm over northern San Saba
County as of 07Z may just clip northern portions of Burnet or
Williamson counties, while additional pop-up storms are also forming
over southwestern portions of the CWA.

These isolated areas of showers and non-severe thunderstorms will
remain possible today per high resolution model guidance, and have
broad brushed slight chance to chance POPs across essentially all
except far northwestern portions of our area. Through the daytime,
drier air will work its way in as the trough continues to slowly
nudge eastward. This should gradually put an end to our rain chances
late this afternoon and evening. Cooler than average temperatures
are expected with highs in the mid 70s to mid 80s.

While the cut-off low was previously advertised to retrograde west
or southwestward, this is no longer forecast by global or regional
guidance. On Wednesday, it will spin near northeast TX and drift
northeastward. A dry morning is expected, however current guidance
suggests a strong mid-level speed max with northwesterlies of 50-60
kts at 500 mb will rotate into areas mainly north and east of San
Antonio. This, combined with sfc south-southwesterlies, will lead to
strong deep layer shear on the order of 50-60 kts. Looks like a good
potential for 2000-3000+ J/kg CAPE to be available, thus the
potential for another round of strong to severe storms exists. Large
hail and damaging winds will be the main threats but a tornado
cannot be ruled out. Timing will need to be refined over the next 24
hours, but storms could move in from the northeast as early as
midday or as late as the evening hours. The best potential at this
time looks to be north and east of a line approximately from
Kerrville to San Marcos to La Grange but the potential exists
northeast of a line approximately from Rock Springs to Halletsville.

LONG TERM (Wednesday Night through Monday)...
The upper level system over the eastern part of the southern Plains
continues to push into the Lower Mississippi Valley on Wednesday
evening. At the surface, winds are expected to be generally from the
south with temperatures in the lower 80s with dewpoints mainly in
the lower 60s over most areas by early evening. As mentioned above
in the short term, strong to marginally severe thunderstorms could
begin on Wednesday afternoon and last through the evening hours
affecting parts of the northeast and southeast of our CWA. The
cluster of storms/MCS continues to push to the southeast and away
from the area on Wednesday night into the overnight hours.

Thursday morning looks to be relatively dry, however, a weak frontal
boundary pushing over the area could trigger showers and
thunderstorms during the afternoon hours. The one thing to monitor
on Thursday afternoon into the evening is a cluster of storms that
develops at the tail end of the frontal boundary over the San
Angelo`s CWA and then moves down into the Rio Grande. Looking at
forecast soundings for Del Rio for the period, there is plenty
instability in the range of 3000 - 3500 J/Kg of CAPE values for the
potential of strong to severe storms capable of producing large hail
and damaging winds. Another thing to monitor closely is for the
potential of an MCV as part of the MCS pushing to the southeast and
affecting the the eastern half of the area overnight/Friday morning.

The MCV is expected to linger around the southwest of our CWA to keep
slight to low chances for showers and thunderstorms on Friday. The
wet pattern continues into the weekend with highs in the mid to upper


Austin Camp Mabry              64  89  66  88  67 /   0  30  20  20  20
Austin Bergstrom Intl Airport  62  89  65  88  66 /   0  30  20  20  20
New Braunfels Muni Airport     62  89  65  90  66 /   0  20  -   10  20
Burnet Muni Airport            60  87  63  85  64 /   0  30  20  20  20
Del Rio Intl Airport           65  95  69  94  69 /   0  -    0  -   30
Georgetown Muni Airport        62  88  65  88  65 /   0  30  20  20  20
Hondo Muni Airport             62  92  65  93  67 /   0  10  -   -   30
San Marcos Muni Airport        62  89  64  90  66 /   0  30  10  10  20
La Grange - Fayette Regional   63  88  65  89  67 /   0  30  20  20  20
San Antonio Intl Airport       64  90  66  91  68 /   0  20  -   -   20
Stinson Muni Airport           64  90  67  92  69 /   0  20  -   -   20




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