RIO GRANDE VALLEY (6/25/2011-6/30/2011)
Short Term Forecast (Tonight-Sunday Night)
An upper-level ridge across Mexico will begin to strengthen and build eastward. As this occurs, the Rio Grande Valley’s rain chances will begin to taper off. However, timing on when the ridge will strengthen is still questionable, as models and Brownsville’s sounding continue showing low level moisture. Therefore, a shower or thunderstorm can’t be ruled out for the Valley in the short term forecast (10% inland, 20% near the coast). Temperatures will be around or slightly above average for Sunday afternoon, in the middle to upper 90s. The coastal areas will be in the upper 80s/lower 90s. Overnight temperatures will be warm and muggy, with temperatures in the middle to upper 70s.
Long Term Forecast (Monday-Thursday)
Because of upper-level ridging, rain chances will be at a minimum for the long term forecast. Surface high pressure in the Gulf of Mexico will provide moderate southeasterly winds for the Valley through Thursday. This flow will also keep dewpoint temperatures and humidity levels high. Temperatures will remain consistent for the most part, with around or slightly above seasonal averages. Perhaps the biggest question in the long term forecast is determining what a weak tropical wave, that is currently in the southwestern Caribbean Sea, will do and if and how it will affect the RGV for the middle of next week. Earlier runs of the computer models brought a lot of moisture from this wave set to enter south Texas/northern Mexico for Tuesday through Thursday of next week. Now, however, recent model runs are holding it back a little longer and has the wave entering central and southern Mexico, keeping most of the rain and moisture south of the Valley. If this isn’t a rain maker for the Valley, it will still produce cloud cover for next week. I will continue updating my blog as this wave gets closer. It is not expected to strengthen any further in the next 24-48 hours. Please visit my tropics page and the National Hurricane Center’s site here for more in depth analysis.