HARLINGEN — Dueling high pressure systems impacting the Rio Grande Valley mean abnormally high temperatures this week with the possibility of three days with rainfall beginning Tuesday.
So far, January has been around the norm when it comes to precipitation, but the week ahead could mean some much-needed moisture will fall.
“Potentially for this coming week we could see a little bit of an uptick in some rain starting around mid-week, just kind of as we get a little bit of convergence flow with a high pressure sitting just off to our east and another one sitting off just to our north,” Brian Adams, a meteorologist with the National Weather Service in Brownsville, said Sunday. “A convergence between those two might kick off some additional showers and extended rain activity, probably about mid-week or so.”
January is one of the lower precipitation months in the Rio Grande Valley, with Harlingen averaging 1.24 inches, Brownsville 1.27 inches and McAllen 1.05 inches.
This month is near the norm for Harlingen (0.46 inches of rain have fallen, about 0.04 percent above average), while Brownsville has received 0.85 inches (about 0.26 percent above normal. Those numbers are through Saturday.
McAllen has received 0.36 inches, which is 0.17 inches below normal.
As any Valley resident with a garden or lawn can attest, the region is quite dry compared with most of the United States, with average annual rainfall for Harlingen totaling 27.49 inches, Brownsville 27.44 inches and McAllen just 22.2 inches.
Just how much rain is in the forecast this week is still something of a mystery, although forecasters say there will be a 20- to 30-percent chance Tuesday, a 40- to 50-percent chance Wednesday and a 10- to 20-percent chance Thursday.
“That’s going to be kind of tricky to pin down, because a slight shift in either one of those areas of high pressure might substantially shift where the axis of heaviest rain would set up,” Adams said. “It seems like the best chance would be across western portions of our area so you’re talking somewhere out closer to Laredo, maybe as far east as McAllen.”
“But as far as us closer to here in Brownsville, now it’s probably looking like it’s going to be a little bit off to our west,” he added. “But again, a shift in that high could mean the axis is closer to McAllen or Brownsville.”
Temperatures this week will be abnormally warm, with highs ranging from the mid-70s to mid-80s most days. Lows will be mostly in the low to mid-60s, with the exception of Monday, where overnight temperatures will dip to between 46 and 56 degrees.
