Rainfall in May obliterated the usual norms here in the Rio Grande Valley, and June is not letting go.

AccuWeather forecasters call for anywhere between one to four inches of rain through Friday, warning again of the possibility of localized flooding since some waterlogged areas could receive far more rain than the forecast indicates.

Farther north, the saturated and soggy ground from Houston to Shreveport can expect eight to 12 inches at a minimum, with the possibility of localized rainfall reaching two feet in some spots.

“Over the next couple of days, what is happening is there’s plenty of moisture in place across the region,” Dave Houk, senior meteorologist for AccuWeather, said Thursday. “We have a weak upper-level trough, but despite being weak, it’ll be enough to squeeze out rounds of rain and thunderstorms across the Valley, probably right through Friday night.

“Once we get into Friday night, Saturday and Sunday, especially Saturday and Sunday, it looks like we’ll get some drying, and we’ll kind of get a westerly flow off the ground which will help dry it out some,” he added Thursday. “I think our real threat for flash flooding and flooding looks like the rest of today and into Friday night.”

Minimum 1-2 inches

The AccuWeather forecast calls for most of the Rio Grande Valley to receive between one and two inches of rain through Saturday.

But Houk stresses the unstable atmosphere could deliver a far bigger punch depending on where you live.

“As far as rainfall amounts, it’s always kind of tough to predict, but with this amount of moisture in the air and this upper low. We saw it in McAllen a couple of days ago where an hour or two of rain and thunder brought over two inches of rain, almost two-and-a-half inches of rain,” he said.

“This looks like one of those patterns where pretty much everybody’s guaranteed one to two inches,” he added. “Some places are going to pick up two to four inches, and some places may pick up six in the next 48 hours.”

Recent rain showers have dropped enough rain to leave areas ponded with water like this one seen Thursday afternoon along 77 Sunshine Strip in San Benito. More rain is expected in the next few days possibly causing more localized flooding. by Maricela Rodriguez, Valley Morning Star

May’s vengeance

The month of May was one of the wettest in recent memory here in the Valley, with rainfall totals soaring above monthly norms from Brownsville to McAllen, AccuWeather climate data shows.

McAllen received the most rainfall for the month with 10.35 inches, more than quadrupling its normal May precipitation of 2.50 inches.

Harlingen received 8.30 inches, more than tripling its normal precipitation of 2.50 inches.

Brownsville, likewise, was far above its usual norm for the month, receiving 5.18 inches of rain in a month when it usually averages 2.22 inches.

Soggy coast

The heavy rainfall of May was widespread along the Gulf Coast, with monthly totals in double digits from the lower Rio Grande Valley to central Texas and much of southern Louisiana.

Houston received more than 11 inches of rain last month — more than twice its average — while Palacios received a record 16.97 inches.

Both are going to get a lot more over the next few days.

“I know we have a graphic out there with eight to 12 inches of rain in parts of the area going into next week, and that certainly seems reasonable,” Houk said.

Yet Houk warned localized precipitation in that region could be more than twice as much as the forecast indicates.

“It’s not going to be one of those things where radar is going to be filled with rain at all times, but certainly there will be heavy rain in there and it’s a pretty widespread flood threat into next week,” he said.

“We talk about as much as two feet of rain … meaning that for someone in there, the potential is for up to two feet of rain out of this,” Houk added. “No rest for the weary.”

Clear, then rain

After a couple days’ reprieve, the Valley can expect some more unstable atmosphere and potential rainfall later next week, Houk says.

The culprits for all this are a pair of high-pressure areas over Colorado and Arkansas. Sandwiched between them, over the Texas Panhandle on Thursday, was a low-pressure system.

The shape of the pattern is allowing a crease through which gulf moisture is coming ashore in South Texas and on up the coast.

“The overall pattern on all the models I’m looking at favors some rain again coming back into the picture Tuesday, Wednesday and into the latter part of next week for us,” Houk said.

“A ridge, a dome of high pressure, is building all across the southern two-thirds of the nation,” he added. “It’s just this weakness left in-between that and the upper low we’re talking about. Until we get rid of that upper low, we’re going to be in this moist pattern.”