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

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FXUS64 KEWX 221132
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
632 AM CDT Tue Aug 22 2017

.AVIATION... /12Z TAFS/
A few bkn mvfr cigs will affect SAT and higher terrain areas to the
NW through around 14z with vfr skies expected for all areas afterwards.
Approaching tropical instability from the SE and a weakening cold
front approaching from the N will help to create a sparse pressure
gradient through the period, leading to light/variable winds and
limited cloud development for the overnight hours Wednesday morning.

&&

.PREV DISCUSSION... /ISSUED 401 AM CDT Tue Aug 22 2017/

SHORT TERM (Today through Wednesday)...
All is fairly quiet across South-Central Texas in the overnight
hours with light winds, mostly clear skies, and temperatures in the
70s and lower 80s. A TUTT low can be seen rotating across the
northern Gulf of Mexico at the present time and this feature will
slowly move west over the next couple of days before dissipating east
of the region. Moisture values will remain low today as is currently
evident by the lack of nocturnal stratus at the present time.
Therefore, most of the area will see no rain chances with only a 20
PoP needed across the eastern counties where there could be some
isolated activity closer to the coast. Otherwise, highs today will be
in the middle 90s to near 100 degrees. A frontal system currently
bringing rainfall to the central plains will be across North Texas
tomorrow afternoon and with slightly higher moisture in place, we
could see some isolated to scattered activity in our CWA, mainly in
the northern and eastern counties. Highs will continue to be in the
middle 90s to near 100 with lows Wednesday morning in the lower to
middle 70s for the most part.

LONG TERM (Wednesday Night through Monday)...
After another day of possible isolated to scattered activity on
Thursday afternoon the focus for the remainder of the forecast shifts
to the Gulf of Mexico and the possible redevelopment of the remnants
of Harvey moving into Texas on Friday and Saturday. The system is
currently moving onto the eastern shore of the Yucatan Peninsula and
will reemerge over open water in the next 24 hours. After this
occurs, development once again into a tropical cyclone is likely with
the latest Tropical Weather Outlook from NHC showing a 70% chance of
development in the next 48 hours and 90% within the next 5 days. We
must continue to stress that the ultimate track and potential
strength of the system will be highly dependent on where a potential
low-level center will close off and at what time. Even slight
variations on where the center develops can sometimes cause large
difference on where the storm goes as it can be picked up into
slightly different steering currents.

Latest consensus with the global models outside of the ECMWF have
shifted north with the potential center of the system moving onshore
over the middle Texas Coast. The system is likely going to find a
weakness in the upper height field left in place with the weakening
TUTT low currently over the northern Gulf of Mexico. If the current
consensus solution verified most of the heaviest rain would fall in
our eastern counties and points to the east. For the official
forecast, will show the higher PoPs across the eastern counties
closer to the current consensus track. However, the ECMWF and
the HWRF continue with a more southwestern potential landfall which
would bring a higher threat of heavier rainfall to the region. Again,
we are likely to see run-to- run shifts on where the system will go
until a closed low does form which could happen in the next 48 hours.
Residents should continue to monitor the forecast as the potential
for a heavy rainfall event does exists this weekend, but is highly
dependent on the ultimate track of the current tropical wave and
possible cyclone.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              98  76  98  75  94 /  -   -   20  20  30
Austin Bergstrom Intl Airport  98  75  98  75  95 /  -   -   20  20  30
New Braunfels Muni Airport     98  73  98  74  96 /  -   -   20  20  30
Burnet Muni Airport            94  73  94  72  91 /  -   -   30  20  30
Del Rio Intl Airport          101  77 101  77  99 /  -   -   20  20  30
Georgetown Muni Airport        96  75  96  74  93 /  -   -   30  20  30
Hondo Muni Airport             99  73 100  73  96 /  -   -   10  10  30
San Marcos Muni Airport        99  74  99  74  95 /  -   -   20  20  30
La Grange - Fayette Regional   99  74  99  75  95 /  10  -   30  30  30
San Antonio Intl Airport       97  75  98  75  97 /  -   -   20  20  30
Stinson Muni Airport           97  74  97  75  97 /  -   -   10  10  30

&&

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

$$

Mesoscale/Aviation...Oaks
Synoptic/Grids...Hampshire



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