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

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FXUS64 KEWX 240425

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1125 PM CDT Wed May 23 2018

Isolated showers and thunderstorms have begun to move into Val Verde
county and have introduced mention of slight chance POPs for that
area. Remainder of the South Central Texas forecast is on track.


.PREV DISCUSSION... /ISSUED 935 PM CDT Wed May 23 2018/

Showers and thunderstorms came to an end around 7 PM this evening and
no other activity is anticipated for the rest of tonight. Those
showers and thunderstorms across the Midland CWA are expected to
dissipate within the next several hours before getting closer to the
far northwest part of Val Verde County.

Otherwise, a warm and humid night is in store with patchy fog
expected around dawn across the Coastal Plains and southeast areas of
South Central Texas and lasting through 8 or 9 am Thursday.

PREV DISCUSSION... /ISSUED 701 PM CDT Wed May 23 2018/

See below for the 00z aviation discussion...

Currently VFR at all sites with east southeasterly winds across south
central Texas. Convection from earlier this afternoon has almost
entirely dissipated across the region. VFR conditions are expected
to continue for the remainder of Wednesday. CIGs are expected to
lower to MVFR at AUS/SAT/SSF around 8z to 9z Thursday morning and by
11z at DRT, with CIGs lowering further at AUS/SAT/SSF to IFR in the
10z to 11z Thursday time frame. VSBY is anticipated to drop to below
P6SM at AUS early Thursday morning as well, with VSBY possibly
briefly dropping to below 4SM at times. Conditions should improve to
MVFR once more by 15z Thursday morning with all sites improving to
VFR by 17z to 18z Thursday afternoon. Winds will remain generally out
of the southeast at all sites. Convection on Thursday afternoon
should remain well east of the Interstate 35 corridor.

PREV DISCUSSION... /ISSUED 250 PM CDT Wed May 23 2018/

SHORT TERM (Today through Thursday)...
A weak coastal trough off of the upper Texas Coast helped initiate
shower and thunderstorm activity across areas around Houston this
morning. That activity now extends from Victoria to Smithville to
Bryan-College Station and is working its way north and west. The
isolated showers and storms will impact areas along and east of the
I-35 corridor through the afternoon before weakening this evening
with the loss of daytime heating. Tonight should be partly cloudy
with more patchy fog expected along the Coastal Plains around
sunrise. Lows will be in the upper 60s and lower 70s, just a few
degrees above seasonal normals. While the coastal trough dissipates
tomorrow, there is plenty of moisture in place for more diurnally
driven afternoon showers and thunderstorms (mainly east of a La
Grange to Gonzales to Karnes City line). Afternoon highs will be in
the low 90s for one more day across the I-35 corridor, but highs
begin to warm across the Rio Grande Plains topping out in the mid to
upper 90s tomorrow. Tomorrow`s forecast high of 96 tomorrow in Del
Rio is 5 degrees above normal for late May.

LONG TERM (Thursday Night through Tuesday)...
For Friday and beyond the forecast dries out across South Central
Texas. The upper level ridge steadily builds in over Central Texas
for the Memorial Day weekend as a low pressure across the eastern
Gulf deepens. High pressure over us means decreasing moisture levels
with both subsidence and a mid-level warm layer keeping a lid on any
potential for seabreeze showers and thunderstorms. Temperatures, as
a result, will be on the rise with 100 degree highs forecast for the
Rio Grande on Saturday, spreading towards San Antonio and the I-35
corridor for Sunday and Memorial Day. Hot and dry is a welcome change
to the record flooding or isolated tornadoes of Memorial Day
weekends past, but it means that those out celebrating on the rivers
and having backyard parties should pay attention to the heat,
drinking plenty of water, etc. After heat index values will reach to
between 101 to 104 each afternoon of the Memorial Day weekend. The
operational ECMWF and GFS disagree on what to do with the low across
the eastern Gulf. While the GFS takes the system into Florida the
ECMWF moves it north towards the Mississippi delta. Neither solution
brings any relief to us in Central Texas, possibly making it worse.
If the tropical/subtropical low does develop (NHC now has the 5-day
chance of formation up to 60%) and moves into the Central Gulf Coast
subsidence and dry air on the western side of the storm could
actually increase the amount of heating and drying across South
Central Texas.


Austin Camp Mabry              70  91  71  93  72 /  10  10  -   -    0
Austin Bergstrom Intl Airport  68  90  69  92  70 /  10  -   -   10   0
New Braunfels Muni Airport     69  91  69  93  70 /  10  -    0   0   0
Burnet Muni Airport            68  90  69  92  70 /  -   -    0  -    0
Del Rio Intl Airport           73  96  73  98  74 /  20   0   0  -    0
Georgetown Muni Airport        68  90  69  92  71 /  10  -   10  10   0
Hondo Muni Airport             69  93  69  94  69 /  10   0   0   0   0
San Marcos Muni Airport        69  91  69  93  70 /  10  10   0   0   0
La Grange - Fayette Regional   69  90  70  92  71 /  20  30  10  20   0
San Antonio Intl Airport       71  92  71  94  72 /  10  -    0   0   0
Stinson Muni Airport           71  93  71  95  72 /  10  -    0   0   0




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