The hottest temperatures in recorded history scorched large portions of the Texas Panhandle, Oklahoma Panhandle, and southwestern Kansas on Sunday. Amarillo hit 111°, breaking its hottest day-ever record of 109° (set just two days previously, on June 24). Borger, Texas hit 113°, smashing the previous hottest day-ever record set on June 24, 2011 of 108°. Dalhart, Texas had its hottest day on record, 110°, beating the 108° on June 24, 2011. Dodge City, Kansas tied its all-time record with 110° (last seen on June 29, 1998). Dodge City has temperature records back to 1874. Yesterday saw the hottest temperatures of the month for Texas with 116.2° at Childress, Northfield, and Memphis (all in the panhandle region.) These readings are not far from the state record of 120° set at Monahas on June 28, 1994 and at Seymore on August 12, 1936.

A cold front moved through the region overnight, bringing northerly winds and cooler temperatures to the region. However, a new ridge of high pressure will gradually build in this week and temperatures are expected to reach near-record levels again by Thursday, with 102°F expected in Amarillo, which is their all-time record for the date. The record-breaking temperatures in Texas are being caused, in part, by the record drought. Under normal conditions, the sun’s heat expends part of its energy evaporating water from the soil and from vegetation. This energy is stored as “latent heat” in the water evaporated, and is not available to heat the air up. However, when a severe drought dries up the soil and kills the vegetation, there is much more heat available to go directly into heating up the air, since there is little moisture to evaporate. The increased temperatures help to strengthen the high pressure system dominating the drought region, making it even more difficult for rain-bearing low pressure systems to bring drought-busting rains. This positive feedback effect is a key reason why we expect more intense droughts and heat waves in a warmer climate.

Wunderground’s weather historian Christopher C. Burt has many more details on the great Texas drought of 2011 in his latest post, updated Sunday night. He reports that Pecos, Texas has had no precipitation since September 23, 2010–one of the longest rain-free periods for a U.S. city in recorded history, outside of the desert regions of Arizona and California.

Figure 1. Latest weekly drought conditions for Texas, as compiled by the U.S. Drought Monitor. West Texas is experiencing its worst drought in recorded history.

Fire threatens Los Alamos, New Mexico
A major wildfire has burned to spot one mile southwest of Los Alamos, New Mexico today, forcing the nuclear laboratory there to close and send home all 11,000 of its employees. The fire was fanned by winds that reached sustained speeds of 32 mph, gusting to 45 mph, along with temperatures in the upper 80s and humidities as low as 9%. Today, winds will be weaker, 10 – 20 mph, but are expected to to turn to the southwest, which would force the fire towards the laboratory. According to the NOAA Storm Prediction Center, these will not be critical fire conditions, and critical fire conditions are not expected to return to the area until Thursday.

Figure 2. Noon satellite image of the tropical disturbance crossing Mexico’s Yucatan Peninsula.

Tropical disturbance approaching the Gulf of Mexico
Heavy thunderstorm activity is increasing over Mexico’s Yucatan Peninsula and adjacent waters due to a tropical wave moving west-northwest towards the Gulf of Mexico. Wind shear is currently 20 – 30 knots, which is too high to permit significant development, but wind shear is forecast to fall to the moderate range, 10 – 20 knots, on Tuesday, as the wave emerges over the Gulf of Mexico. Several of our reliable computer models are predicting that a system that may approach tropical depression strength could form in the southern Gulf of Mexico in the Bay of Campeche Tuesday or Wednesday. NHC is giving the system a 20% chance of developing into a tropical depression by Wednesday. Development will be hindered by a large region of dry air to the west, associated with the great 2011 Texas-Mexico drought. However, the topography surrounding the Bay of Campeche tends to boost counter-clockwise air flow, enabling systems there to spin up faster than any other portion of the Atlantic.

There is a strong ridge of high pressure over the Gulf, which should act to keep any storm that might form far to the south, with impacts limited to Mexico and perhaps extreme South Texas. Mexico could use the rain. A report from The Latin American Herald Tribune states that 40% of the nation is experiencing its worst drought in 70 years. There are portions of the state of Coahulia where no rain has fallen since last September (just like Pecos in Texas). Wild fires have so far burned 500,000 acres in northern regions near the U.S. border.

Jeff Masters