Rio Grande Valley
…Short Term (next 36 hours)…
Tonight should be relatively the same as previous nights, warm and muggy under partly cloudy skies. Mid-level high pressure ridge over the central United States will continue to dominate over the RGV. Surface high pressure in the eastern Gulf of Mexico will continue to produce south/southeasterly winds.
Sunday, there will be a slight increase in moisture from the Gulf of Mexico to help increase rain chances a little. However the mid-level ridge will still be very strong and will cap off significant chances at rain, but a few showers or thunderstorms cannot be ruled out for Sunday. Any rain that does form will be short-lived and non-severe. The most probable chance of rain will be during the afternoon/early evening hours. Where and when rain isn’t falling, afternoon temperatures will be in the lower to middle 90s under mostly to partly cloudy skies. It is possible that the upper Valley may reach the lower 100s in spots. Winds will shift back and forth from southeast to south-southeast throughout the day around 10-20 mph.
…Long Range Forecast (Monday-Wednesday)…
Moisture transport from the Gulf will persist into Monday, which looks to be an enhanced sea breeze event during the afternoon hours. The mid-level ridge will continue to be dominate over the area, therefore, there is a better chance that rain won’t fall. But, any weakness in the ridge will spark showers. All in all, I am going with a 20% chance of rain for Monday and even less of a chance for Tuesday. Ridging and surface high pressure will build strong again after Tuesday, so you can expect hot and dry weather for Wednesday.
Temperatures will remain around or just slightly above average for this time of year in your long range forecast. Lower Valley will be in the lower to middle 90s and the upper Valley will be in the middle to upper 90s, with lower 100s possible. Winds will generally be out of the southeast/south-southeast, with the exception of Monday, where winds will be out of the east-southeast, providing that more easterly component for the sea breeze event.