A fairly typical late August weather pattern continues across Central and South Texas. While afternoon temperatures have been warm for the past few days, they've actually been slightly below normal for this time of the year. Some changes to the current pattern are forecast beginning Friday as circulation around a ridge of high pressure along the East Coast pulls tropical moisture into Texas off the Gulf of Mexico. This feed of moisture will likely cause the development of scattered rain showers and thunderstorms across the region through the middle of next week.
A visible satellite image from late Thursday afternoon showed scattered thunderstorms clouds along the middle and upper Texas coastal plains where the leading edge of the tropical moisture had spread inland. Additional clouds can be seen over the western and Central Gulf of Mexico, associated with a weak non-tropical area of low pressure.
With a slightly unstable atmosphere in place, Gulf moisture spreading into Texas is expected to cause a daily chance for rain and thunderstorms across the region. The most favorable area for rain through the period will be across the coastal plains region, with less activity expected across Central Texas and even less expected across the Hill Country.
For Friday and Saturday, the probability for scattered rain showers and thunderstorms will range from 50 percent near the coast to around 40 percent across Central Texas to near 20 percent across the Hill Country. 2-day rainfall totals are forecast to average around a half inch across the coastal plains and around a quarter inch at most other locations. Isolated totals of 1-2 inches will be possible. Expect a partly to mostly cloudy sky with high temperatures in the low 90s.
The chance for rain and thunderstorms will increase Sunday into Monday when the weak area of low pressure over the Gulf of Mexico pushes inland and slowly tracks to the west. The chance for rain looks to be near 40-50 percent at most locations and 2-day rain amounts are forecast to average between 0.25 and 0.50 inch. Isolated totals of 1-2 inches will again be possible. The sky will be mostly cloudy both days with high temperatures near 90 degrees.
A slight chance for rain showers is forecast to continue next Tuesday and Wednesday as tropical moisture lingers across the area. Rain amounts are forecast to average around a quarter inch, or less. Expect a partly cloudy sky with high temperatures mostly in the low 90s.
Total rain amounts over the next week are not expected to be all that heavy. The National Weather Service's rainfall forecast for the period from 7 pm Thursday through 7 pm next Thursday are forecast to average near 1-1.5 inches across the coastal plains, around a half inch across Central Texas and close to a quarter inch across the Hill Country.
Long-range forecast solutions call for the development of a generally dry and warm weather pattern late next week into next weekend when a broad ridge of high pressure in the upper atmosphere develops across Texas and the southern Plains states. Circulation around the ridge is expected to decrease the flow of tropical moisture into Texas. High temperatures late next week are forecast to be in the low to mid 90s. There are some signs a few showers may return to the forecast beginning around Labor Day.Tropical Weather Update
Forecasters continue to monitor the progress of a strong tropical wave located in the southeastern Bahamas and tropical storm Gaston, located in the central tropical Atlantic. NOAA-NASA GOES Project
The strong tropical wave remains a disorganized system and has so far failed to develop into tropical cyclone. The tropical wave and an associated broad area of low pressure was centered Thursday afternoon just north of the Hispaniola and was moving westward at 15 to 20 mph through the southeastern Bahamas. Satellite wind data and reports from an Air Force Reserve reconnaissance aircraft this morning indicated the system still lacked a closed circulation, and that the strongest winds associated
with the system likely had decreased to below tropical storm strength. In addition, shower and thunderstorm activity had become
significantly less organized during the past 24 hours due to increased wind shear. NHC forecasters pointed out that although upper-level winds are not conducive for significant development during the next day or so, they could become a little more favorable over the weekend or early next week when the wave is expected to approach southern Florida or the southeastern Gulf of Mexico. NHC forecasters are giving this system a 70 percent chance for tropical development over the next 5 days. The majority of the long-range computer guidance suggests this system, whether it develops or not, will most likely track toward the eastern Gulf of Mexico, and not westward towards Texas. Nevertheless, the progress of this system will need to be monitored closely.
Tropical storm Gaston continues to churn across the central tropical Atlantic. Late Thursday afternoon, Gaston was centered about 1105 miles east-northeast of the Leeward Islands, moving to the northwest at 17 mph. Maximum sustained winds were near 65 mph. Strong southwesterly winds in the upper atmosphere over the past 24 hours caused Gaston to weaken. Little change in strength is forecast through Friday afternoon, but the system is forecast to strengthen into a hurricane Saturday, when it moves into a more favorable environment. Long-range forecasts call for Gaston to remain over the open Atlantic for the next several days, not threatening any land areas.