South Texas Weather Forecast
Weather forecast for September 22, 2017
September 22 – 24, 2017
Daily Weather Forecast
South Texas Weather Modification Association

Weather Discussion:
Partly to mostly cloudy across south Texas this morning, with scattered fog east and northeast
of San Antonio.  Fog looks to last through the early morning hours.  A broad area of high
pressure is centered over the eastern US, with southeasterly winds bringing moisture from the
Gulf into TX.  With slightly drier air than yesterday, isolated afternoon showers and
thunderstorms are possible across the region.  High temperatures in the upper 80’s, lower 90’s,
with warmer temps over the Rio Grande Plains.  Partly then mostly cloudy overnight with low
temps in the lower to mid 70’s, and cooler temps over hill country.  Fog possible after midnight.  

Similar conditions continue Saturday with mostly cloudy skies in the early morning, then partly
cloudy with isolated afternoon showers and storms.  Chance of rain is slightly higher west of San
Antonio as a strong system approaches from western TX.  Saturday high temps in the upper 80’
s, lower 90’s.  Partly then mostly cloudy overnight Saturday.  Isolated overnight showers are
possible along the coast.  Saturday low temps in the lower to mid 70’s, and cooler temps over hill
country.  A strong cold front looks to move west to east across the state on Sunday, with
isolated to scattered afternoon showers and thunderstorms.  Sunday high temps in the upper 80’
s, lower 90’s.  Chance of rain continues overnight Sunday into Monday morning.  The front then
appears to stall across west/central TX.  This pattern will likely lead to rain both Monday and
Tuesday, however it is too early to tell if rain will be isolated/scattered or more
scattered/widespread.

Daily normal (F): high 89, low 67

Pilots (STWMA): possible cloud seeding today.  

Today: Mostly then partly cloudy.  Fog possible in the early morning hours.  Isolated afternoon
showers and thunderstorms possible across the region.  High temps in the upper 80’s, lower 90’
s, with warmer temps over the Rio Grande Plains.  Southeasterly winds 5 – 15 mph.

Tonight: Partly then mostly cloudy.  Fog possible after midnight.  Low temps in the lower to mid
70’s, and cooler temps over hill country.  Southeasterly winds 5 – 15 mph with stronger gusts in
the evening, then decreasing overnight.

Saturday: Mostly cloudy in the morning, then partly cloudy with isolated showers and storms in
the afternoon.  Highs in the upper 80’s, lower 90’s.  Partly to mostly cloudy overnight with
isolated showers along the coast.  Overnight low temps in the lower to mid 70’s, with cooler
temps over hill country.  Southeasterly winds 5 – 15 mph.

Sunday: Partly cloudy with isolated to scattered afternoon showers and thunderstorms.  High
temps in the upper 80’s, lower 90’s.  Mostly cloudy overnight with isolated showers and storms.  
Overnight lows in the lower to mid 70’s.  Easterly winds 5 – 15 mph.

Extended: Rain likely both Monday and Tuesday (September 26).


Forecast Notes:
Temperatures are in Fahrenheit (F)
Wind speeds are in miles per hour (mph)
Rainfall amounts in inches (in.)
Visibility in miles

Rain chance terminology from lowest to highest chance: isolated, scattered, widespread.
South Texas Weather Modification Association