A prolonged and deadly heat wave in Mexico, one of the most extreme the country has faced, shows little sign of easing and is oozing into the United States, where it has already set records and fueled violent storms.

The heat has been breaking records in Mexico since early May. Many Mexican states have observed their highest temperatures on record, while more than 80 percent of the country is also enduring drought. Mexico City has set all-time record highs on multiple occasions, while fears grow that it may run out of water.

At least four dozen people have died of heat stroke and dehydration in Mexico over the past two months. And the heat is taking a toll on wildlife, too. Nearly 150 howler monkeys have died because of the high temperatures.

There’s little sign of relief. Researchers at the National Autonomous University of Mexico warned last week that the country “will experience the highest temperatures ever recorded” into early June.

Advertisement

Meanwhile, there are signs that the intense zone of high pressure fueling the high temperatures, known as a heat dome, may expand northward into the western United States over the next week.

Here’s how it has been in Mexico

Mexico City soared to 94.5 degrees (34.7 Celsius) both Friday and Saturday, its highest temperature in 150 years of data keeping, according to the country’s National Meteorological Service. The capital city also set calendar day record highs above 90 degrees Sunday and Monday. These temperatures may not seem that high, but are exceptional for a city with an elevation of over 7,000 feet.

At lower elevations, temperatures were much higher, approaching 122 degrees (50 Celsius).

In southern Mexico, the temperature hit 118.4 degrees (48 Celsius) at Valle Nacional over the weekend, marking Oaxaca state’s hottest day, according to climate historian Maximiliano Herrera. The high of 116.6 degrees (47 Celsius) recorded in Monclova, a mountainous area about 120 miles southwest of Laredo, Tex., set an all-time high for Coahuila state.

Advertisement

The heat is worsening the drought affecting much of the country, by speeding up the evaporation of water from the land surface. About 80 percent of the country was in drought — 30 percent severe or extreme — in the most recent update from the North American Drought Monitor. The heat and drought are intensifying fires erupting in a number of areas.

Border-hopping heat

The heat dome responsible for the heat in Mexico has at times flexed northward into the southern United States, particularly southern parts of both Texas and Florida.

The heat index, a measure of how hot it feels factoring in humidity, reached at least 115 degrees on Memorial Day at Houston Hobby Airport, demolishing the previous May record of 108 degrees from 1998. The 115-degree heat index exceeded the typical peak summer high of 111 degrees. Similarly brutal heat indexes swelled into the Florida Keys and South Florida from the same heat dome about 10 days ago.

Advertisement

The heat swelling into Texas has also fueled violent thunderstorm complexes that have blasted Houston and Dallas in the past two weeks.

Temperatures have regularly risen near or above 110 degrees in parts of far southern Texas since May 18. Rio Grande Village has seen highs hovering between 110 and 115 for much of that time, including a high of 115 on Monday. Del Rio reached 112 degrees Sunday, a May record

Many places in South Florida and southern parts of Texas have set multiple record highs this month, including West Palm Beach (9 record highs); Brownsville, Tex. (9); Fort Lauderdale (8); Key West (7); and Del Rio (7).

Many of the above locations are seeing their warmest May on record, as are Miami, Tampa and Orlando.

A handful of additional record highs are predicted in the coming days, first in Florida, and perhaps again in Texas next week.

Heat to build northward

As the core summer months approach, the hot weather pattern is expected to continue, only briefly easing at times.

Over the next one to two weeks, the heat dome is forecast to build some to the north and west. As it continues to bake Mexico and Texas, its northward expansion may allow for the first heat wave of the season in the western United States in 7 to 10 days. Florida may see some relief from the heat because of a dip in the jet stream over the eastern United States.

The National Weather Service’s Climate Prediction Center issued an outlook calling for a slight to moderate risk of excessive heat in much of the West between June 5 and 11.

The heat dome over Mexico is probably being intensified by marine heat waves in the eastern Pacific Ocean, Gulf of Mexico and Caribbean. The magnitude of the warmth over both the land and ocean is tied to the El Niño climate pattern and human-caused climate change, which have pushed temperatures to record levels.

Jason Samenow contributed to this report.

ncG1vNJzZmivp6x7uK3SoaCnn6Sku7G70q1lnKedZMSmrdOhnKtnYmV%2FdXuPbmZrcF%2Bisrm1wqhkoZ2RqXqlu8yeZK2dqJbAbrLLqKminJFixKa%2F02g%3D