El Nino pattern to bring soggy days to the RGV

The Rio Grande Valley is in for a dose of fall-like weather and wet skies as another cold front sweeps in early Friday, according to forecasters with the National Weather Service Brownsville-RGV station.

It’s part of a trend toward wetter weather that started last month, though October’s rain totals were still at or just below normal, and that probably will make rain even more likely through late autumn into mid-winter thanks to a moderate to strong El Nino, the climate pattern characterized by unusually warm ocean temperatures in the Equatorial Pacific.

NWS meteorologists are predicting extensive rainy conditions and cooler-than-normal temperatures for Veterans Day through early next week. It’s not expected to rain hard enough to cause flooding, though localized ponding of water in low-lying and flood-prone areas could occur during periods of “persistent moderate to heavy rainfall,” according to the NWS.

Forecasters see a “good chance” for showers and scattered thunderstorms as the front moves through Friday morning, with potentially heavy rainfall at times. The front will stall offshore later in the day, with a coastal trough (low-pressure area) forming along the front. Abundant moisture from the Gulf and the Pacific will overrun the front, keeping rain in the picture through Monday and possibly longer, meteorologists said.

Valley residents can expect steady rain on and off over at least four days starting Friday, potentially producing rainfall amounts of 2-4 inches and even 5-6 inches in a few isolated spots, according to the NWS. From highs in the high 80s to low 90s across the Valley on Wednesday, temperatures will plummet starting Friday, falling to mid- to high 50s by early Saturday morning.

Weekend highs in the upper 50s to mid-60s and lows in the mid- to upper 50s are expected. Wind chill won’t be significant, though it will feel like the 50s during rainy, breezy periods, the NWS said.

Longer term, there’s a good chance that a “general trough of low pressure” will form from the Southwest through west of Baja California. Rain chances for the Valley and Falcon International Reservoir increase with the trough tapping into tropical moisture from the Eastern Tropical Pacific, according to forecasters, who expressed “medium confidence” that the trend will continue through winter.

“There are very favorable signs for the trough pattern to develop for mid- to late November, which would favor at least some beneficial rainfall,” the NWS said. “But still not known is whether that pattern will become dominant through December-February or beyond.”

Overall, temperatures are expected to remain above average through November, with equal likelihood of above-average, average or below-average temperatures in December and January, forecasters predicted.

“The temperature forecast through November ensures that all Valley locations will finish among the top-10 warmest on record for 2023, even if December ends up slightly below average,” meteorologists said. “Above normal November and December temperatures would lock down number one warmest (year) on record at Brownsville, Harlingen and Port Mansfield.”

The NWS said to expect more “gray northers” such as occurred around Halloween but not much in the way of serious cold weather December through January.

“At this point, we’re not expecting a widespread hard freeze, but a couple of minor freezes can’t be ruled out,” forecasters said. “All that said, just like with the hurricane season, it only takes one situation to present a hard-freeze opportunity if the pattern briefly allows an Arctic plunge from northwest Canada between December and January. During a moderate to strong El Nino winter, the probability is very low, but non-zero.”