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

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FXUS64 KEWX 240004

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
704 PM CDT Tue May 23 2017

Severe potential is decreasing quickly over the I-35 corridor and we
were able to clear these areas from the watch. The remaining counties
to the southeast should see the storms pull away by around 830 pm,
and another update is planned at that time.


.PREV DISCUSSION... /ISSUED 634 PM CDT Tue May 23 2017/

Storms are rapidly pulling away from the I-35 TAF sites and should
be clear of all the ewx counties by around 02Z. Some gusty winds will
remain possible over the next 2-3 hours but winds are forecasts to
ease up by late evening. Post frontal cigs should remain vfr for the
I-35 TAF sites and clear out in the mid to late evening hours.

PREV DISCUSSION... /ISSUED 215 PM CDT Tue May 23 2017/

SHORT TERM (Tonight through Wednesday Night)...
The cold front is currently beginning to enter our CWA and is best
evident by pressure rises behind the frontal boundary. Winds ahead of
the front are already out of a northerly direction as a boundary
associated with a dying complex of storms this morning came through
the area. This will decrease our surface convergence when the actual
front makes it to the region. This should overall limit the coverage
of showers and storms for the northern Hill Country for surface based
activity. Storms will be more likely to fire across the southern
half of the region where surface winds are lighter and convergence
will be maximized. However, elevated showers and thunderstorms can be
seen on area radars to our north and this activity is developing
under the influence of strong lift as evident on water vapor
imagery. This is evidence that we will have plenty of upper support
for sustained convection later today. As the strong lift arrives, we
could also see some elevated convection behind the front as well as
any boundary layer convection that develops along the frontal
boundary. CAPE values this afternoon will be in the 2000-3000 J/kg
range with the higher values maximized across the eastern CWA. 0-6 km
shear values near 50 knots will definitely support supercellular
structures with any of the stronger activity. Large hail will
initially be the main threat from any severe thunderstorms, but there
could be some high wind reports as well especially later in the
afternoon and evening. Thunderstorm chances will end from north to
south in the late afternoon and evening.

Cooler air is expected to filter into the region behind the front as
is already evident by the near 60 degree temperatures in the Abilene
region north of the front. Lows tonight should bottom out in the 50s
for much of the area with some upper 40s even possible across low-
lying areas in the Hill Country. The only record that could be broken
tonight is Austin Bergstrom airport where the current forecast is 2
degrees under its record low. For tomorrow, clear skies will be in
place across the region with light winds. Should be nice overall,
with highs in the lower to middle 80s over much of the area.

LONG TERM (Thursday through Tuesday)...
The beginning of the long-term forecast will be dry with with
increasing temperatures. Highs on Thursday will quickly be back into
the lower 90s with even some upper 90s across the southwestern CWA.
Temperatures will even be a couple of degrees warmer on Friday as an
upper ridge builds to our south. Lows Friday morning will also be
warm, in the lower to middle 70s.

The upper air pattern will begin to shift on Saturday as a longwave
trough begins to move through the central CONUS. Should see the first
effects of this on Saturday night with some possible warm air
advection activity ahead of an approaching cold frontal boundary.
This frontal boundary will approach the CWA on Sunday and this will
bring an increase to the precip chances to the area. It looks like a
decent chance of showers and storms will remain in the area behind
the front on Memorial Day and into Tuesday as southwest flow remains
in place across the region. Will forecast 30-40 PoPs in this period
for now, but these may have to be increased over the next several
days. Instability amounts on Sunday could support some strong storms,
but this could change as we near the weekend, and will continue to
monitor the chances of stronger convection.


Austin Camp Mabry              56  85  64  91  74 /  10   0   0  -   -
Austin Bergstrom Intl Airport  55  84  61  91  74 /  20   0   0  -   -
New Braunfels Muni Airport     54  85  61  91  74 /  10   0   0  -   -
Burnet Muni Airport            52  83  61  90  72 /  10   0   0  -   -
Del Rio Intl Airport           57  86  64  94  74 /  10   0   0  -   -
Georgetown Muni Airport        54  83  62  91  74 /  10   0   0  -   -
Hondo Muni Airport             52  86  61  93  74 /  10   0   0  -   -
San Marcos Muni Airport        54  85  61  92  74 /  20   0   0  -   -
La Grange - Fayette Regional   55  84  62  90  74 /  50   0   0  -   -
San Antonio Intl Airport       55  86  64  92  74 /  10   0   0  -   -
Stinson Muni Airport           57  86  62  92  75 /  10   0   0  -   -




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