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

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FXUS64 KEWX 250224 AAA
AFDEWX

Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
924 PM CDT Mon Jul 24 2017

.UPDATE...
Convection has come to an end across the area with partly cloudy
skies expected rest of tonight. Overnight lows will generally range
from the low to mid 70s. Clouds will increase overnight mainly
east and south of Interstate 35 as dewpoints remain in the lower 70s.
The shear axis responsible for the development of storms earlier is
expected to push farther to the east of South Central Texas by
Tuesday while the subtropical upper level ridge builds into the
southern Plains. This will limit any convection to form and affect
the area on Tuesday.

&&

.PREV DISCUSSION... /ISSUED 632 PM CDT Mon Jul 24 2017/

AVIATION...
Light rain continues around KAUS and will mention VCSH for the next
couple of hours then show a rain free forecast. No rain is expected
for the rest of the terminals this evening. Should see some possible
MVFR ceilings by morning for the I-35 sites and will show that in the
TAFs. VFR is expected to prevail by noon. Low chances of rain will
be in the forecast tomorrow, but probabilities are too low to mention
any precip at this time. Otherwise, southerly flow should prevail
for most of the period outside any short changes in duration behind
convective outflow boundaries.

PREV DISCUSSION... /ISSUED 307 PM CDT Mon Jul 24 2017/

SHORT TERM (Tonight through Tuesday Night)...
Scattered showers and thunderstorms have developed again across
Central Texas and portions of the northern Hill Country. This
convection is being aided by interaction of a previous outflow
boundary and a mid level shear axis. These showers and storms will
continue south through the remainder of the afternoon and dissipate
around sunset. Showers and storms should impact portions of the
Austin metro area and back west through the Hill Country. Do not
think at the moment it will reach the San Antonio metro area, but
outflow boundaries could. SPC mesoanalysis indicates a mixed layer
CAPE pool of 2000-2500 J/kg and DCAPE values of 1000-1300 J/kg just
out ahead of the ongoing convection across Central Texas and
stretching back through the western Hill Country. Therefore a few
stronger storms will be possible, producing small hail and wind
gusts up to 50 mph, in addition to frequent cloud to ground lightning
strikes.

The mid level shear axis weakens and slides further south on Tuesday
and some mid level drying is indicated by the models. Most of the
hi resolution guidance along with the GFS and ECMWF is indicating low
chances for afternoon showers and storms across the southern and
southeast zones Tuesday afternoon, with coverage remaining isolated.
Otherwise continued warm conditions, with afternoon heat indices
ranging from 104-108 in most areas outside of the Hill Country.

LONG TERM (Wednesday through Monday)...
Moisture remains confined to mainly southeast zones Wednesday with
a slight chance of afternoon showers and storms. Then the ridge
builds over the area through the end of the work week with
temperatures warming further. It appears there could be some
opportunities for Heat Advisories Wednesday through Friday over
portions of the area.

The ridge looks to amplify over the Rockies during the weekend with
a downstream trough digging across the eastern U.S. A backdoor cold
front is indicated by the GFS to work into the area Saturday night
into Sunday and by the ECMWF Sunday. This could bring some better
chances for rainfall to the area Sunday into Monday along with
slightly cooler temps.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              77 100  78 101  77 /  -   -    0  10  -
Austin Bergstrom Intl Airport  75  99  76 100  75 /  -   -   -   10  -
New Braunfels Muni Airport     75 100  76 100  75 /  -   10  10  10  10
Burnet Muni Airport            74  97  75  98  75 /  -   -    0  10  10
Del Rio Intl Airport           78 100  78 101  78 /   0   0   0  10  -
Georgetown Muni Airport        76  99  77  99  76 /  -   -    0  10  -
Hondo Muni Airport             76 100  76 101  75 /   0  -   10  10  10
San Marcos Muni Airport        75 100  76 100  76 /  -   10  -   20  10
La Grange - Fayette Regional   76  99  77  99  76 /  -   10   0  20  -
San Antonio Intl Airport       77 100  77 101  77 /  -   10  10  10  10
Stinson Muni Airport           77 100  77 101  76 /   0  10  10  10  10

&&

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

$$

Mesoscale/Aviation...Hampshire
Synoptic/Grids...17
Public Service/Data Collection...YB



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