USA Weather Summary: Feb 2011

Climate Highlights – February *
During the month’s first half, a southward-plunging polar jet stream held temperatures as much as 15 ??F below normal in much of the Central and Southern United States.

Warm tropical air advanced northward across these regions during the second half of the month, and average temperatures reversed to nearly 15 ??F above normal.

This flip-flop resulted in near-normal temperatures for February as a whole.

* Conditions were persistently warm throughout the entire month in the extreme Southeast, resulting in above normal averages for the region. Below average temperatures affected much of the western U.S.

The precipitation pattern in February was well defined.

Most of the Gulf and Atlantic Coast states experienced below average precipitation. It was the eighth driest February in Louisiana and Mississippi (tied 1954).

* A continuous flow of moisture contributed to above normal precipitation in: Ohio (fifth wettest), South Dakota (sixth), and Indiana (tenth).

* Two severe weather outbreaks during February’s last week brought the month’s preliminary tornado count to 59. The final tornado count for February 2011 will likely rank among the ten busiest Februaries on record.

* The year-to-date period (January – February) was the ninth driest such period on record for the Contiguous United States. For the period, three times as many states had below normal precipitation than those with above normal.

It was the second driest such period in Virginia, fourth driest in New Mexico, and seventh driest in North Carolina. Much of the west, south and southeast also had precipitation below the 20th century average.

* Several record breaking snowstorms caused the U.S. to have above average snow cover extent during February. The “Groundhog Day Blizzard” dropped at least 5 inches of snow in 22 states.

On February 10th, nearly two thirds of the contiguous U.S. was snow covered with every state except Florida having snow on the ground.

* Dry conditions across the southern and southeastern U.S. were associated with much-above average wildfire activity during February. Across the country, 8,226 wildfires burned approximately 187,000 acres – the most February wildfires during the 21st Century and the second most acreage burned.

* Drought coverage, as indicated by the U.S. Drought Monitor, continued to expand during February. As of March 1, 27.9 percent of the United States was affected by D1-D4 (Moderate-Exceptional) drought. Many of the areas that were experiencing drought at the beginning of February only saw conditions worsen through the end of the month.

Across southern New Mexico, Arizona, and western Texas, drought conditions worsened from moderate to severe. Severe drought also expanded across the Front Range in Colorado and across central Oklahoma during the month.

Severe and extreme drought expanded across most of Texas, and the footprint of extreme drought grew across the Lower Mississippi River Valley. Moderate drought conditions developed across northern Alabama and Mississippi and severe drought covered much of the Carolina Piedmont.

National Overview: