National Weather Service United States Department of Commerce

Severe Thunderstorms in the Northern Plains and Upper Midwest; Critical Fire Weather in the West; Dangerous Heat in the Central and Eastern U.S.

Severe thunderstorms are likely today across the northern Plains and into the upper Mississippi Valley. Gusty winds and dry conditions will result in widespread critical fire weather through Saturday across parts of the Four Corners region and the Great Basin. A significant and dangerous heat wave will expand from the Central U.S. into the Eastern U.S this weekend through much of next week. Read More >

The graph below details temperature impacts during the winter months (December through February) associated with La Niñas of the indicated intensity in Alabama Climate Division 1.  The winter temperatures are divided into terciles, or the coolest third, the middle third, and the warmest third of all winters.  The temperatures associated with these groups are indicated on the graph.  For example, for all winters since 1896 for this climate division, the coolest third had average temperatures of 34.3°F to 41.3°F.  It will be important to pay particular attention to La Niñas of strong intensity, since that is the anticipated magnitude of this winter's event.  Notice in the graph below, for example, that not a single winter during all of the strong La Niña events since 1896 were among the coldest third.  In fact, of the 5 winters during strong La Niñas, two were in the warmest third and three in the middle third of all winters.  This does not necessarily mean that temperatures this winter are guaranteed to rank in the middle or warmest third of all winters, but that certainly has been the trend in past.

 

Chart of Winter precipitation based on La Nina strength for Alabama Climate Division 1

 

The graph below shows La Niña's effect on average winter temperatures since 1896. Notice that average temperatures rise during moderate and strong La Niña events, and are about 1.0°F warmer during strong La Niña winters than the average for all years.  Interestingly, notice that the standard deviation, or variability, of average winter temperatures decreases significantly in strong La Niña winters. 

 

Chart of Winter precipitation averages based on La Nina strength for Alabama Climate Division 1