South Texas Weather Forecast
Weather forecast for June 20, 2018
June 20 – 23, 2018
Daily Weather Forecast
South Texas Weather Modification Association

Upper air analysis shows a low circulating over Southern Texas with trough across the Northern
Mississippi Valley and high pressure to the east.  At the surface, low trough axis is located
across the southern Rockies with the low associated with the tropical disturbance over deep
South Texas.  The flow at upper levels is from the northeast with it light and from the east at the
surface. The current dew point temperature is in the mid 70’s with low base clouds hovering over
our area and rain showers over the Coastal Plain Counties and moving inland. For today, the
tropical low will continue to impact our weather brining moisture from of the Gulf of Mexico while
producing showers and thunderstorms to much of the target zone. This low is forecast to spin in
a stall state through this evening before pushing southwest across northeastern Mexico.  Due to
the trough to the north and upper ridging to the east and west, this low has no other choice but
to push southwest while weakening.  Expect another inch of steady light to moderate rainfall
today except for areas under thunderstorms where an additional .5 to 1 inch of precipitation is in
effect. Base on the latest WRF-HiRes model suggest as yesterday, that much of the heavier
precipitation will be along the Coastal Plains with a few isolated thunderstorms making there way
inland. The HRRR and the HiRes NAM brings in more precipitation inland than the WRF and has
been known since the beginning of this event to do pretty well with this storm.  They strongly
agree on the time that this morning showers and thunderstorms should end around 18UTC and
the next batch that moves in mainly along the southern Coastal Plains Counties around or after
22UTC. Even though much of the rainfall may cease after 18UTC, light showers can still linger
into the afternoon and evening hours as we are expected to be under cloudy to mostly could
skies for much of the day. For tonight, except showers to continue especially for the for counties
south of San Antonio.  Should also mention that the low tonight will above the average due to
increasing cloud cover with no radiational cooling taking place while the high is forecast to be in
the mid to upper 88’s courtesy of this low.  For tomorrow, precipitation chances go down as
aforementioned, that the low is expected to be moving out of our area and as it does active
conditions will go with it.  For Friday and Saturday, much more quiet weather is in store as an
upper level ridge builds in drying us out and increasing the high temperatures. The highs for
those days are forecast to be in mid to upper 90’s and in even low 100’s in some inland areas.

STWMA:

Daily Normal (Pleasanton): High 93, Low 70                
                
Pilots (STWMA):  No ops are expected today.
                                                               
Forecast (Pleasanton):         
                                               
Today: Cloudy skies with winds from the east between 5 and 10mph.  Showers and
thunderstorms likely. High temperature of 88°F.
                               
Tonight: Cloudy skies with winds from the east between 5 and 10mph. Chance for showers and
thunderstorms. Low temperature of 75°F.
                                                       
Thursday: Mostly cloudy skies with winds from the east southeast between 5 and 10 mph.  Low
chance for showers thunderstorms. High temperature of 93°F. Overnight, partly cloudy skies
with winds from the south southeast between 5 and 10mph. Slight chance for showers and
thunderstorms before midnight. Overnight low temperature of 76°F.
                                                               
Friday: Mostly sunny skies with winds from the south between 5 and 10mph. High temperature of
98°F. Overnight, mostly clear skies with winds from the south southeast between 5 and 10 mph.
Overnight low of 77°F.

Saturday: Sunny skies with winds from the south between 10 and 15mph with possible gust up to
20mph. High temperature of 100°F.  Overnight, mostly clear skies with winds from the south
southeast between 10 and 15mph with possible gust up to 20mph. Overnight low of 79°F.
               
Extended: Hot and dry conditions are forecast for this weekend into next week with the exception
of a slight chance for showers and thunderstorms from the sea-breeze activities mainly for
Coastal Plain Counties.  

Forecast Notes:
Temperatures are in Fahrenheit (F)
Wind speeds are in miles per hour (mph)
Rainfall amounts in inches (in.)
Convective Available Potential Energy (CAPE)
Convective Inhibition (CIN)
South Texas Weather Modification Association