Flood, Fire, and Frost
Several interesting items crossed the weather desk lately.
LONGER FROST-FREE SEASONS
Old Jack Frost may be working less in the winter lately. Changing circulation patterns in the atmosphere appear to be creating longer growing seasons in the United States. The dominant effect is an earlier end to the last spring freeze. According to Climate Central, using data from the United States National Climate Assessment, the greatest change is over the western and southwestern states where the length of the frost-free periods has increased by nearly three weeks compared to 1901-1960. The researchers warn, however, that untimely freezes will still inflict major damage to crops and trees primed by warm spells in late winter and early spring. Recall that International Airport did not record a freeze after January 9, the earliest occurrence ever documented.
WESTERN FIRE SEASON
The period from November 2016 through April 2017 has been kind to the western United States, a region plagued by a negative moisture balance. California, Idaho, Nevada, and Utah saw much more precipitation than normal. This is very important because not only does it replenish water supplies for urban and agriculture use, it helps dampen the risk of wildfires. The National Fire Information Center (NFIC) expects most of the western United States to have below average wildfire potential through the summer. The caveat is that grassland and brush fires may be worse over parts of California and Nevada. Lush growth promoted by wet winters can become parched quickly during the episodes of hot, dry downslope winds. Parts of Florida and Georgia are also at risk for elevated potential for wildland fires this summer.
THE MISSISSIPPI RIVER IS RISING
Contrary to earlier hydrologic outlooks, the lower Mississippi River continues to rise because of additional rain and increased flow from the Arkansas River system. At Natchez, the river is expected to rise and crest at 55.3 feet on Sunday, May 28. If that happens, it will be the ninth highest crest on record at Natchez but below the historic floods of 2011, 1927, and 1937. At Red River Landing, a crest of 58.5 feet is expected Monday, May 29. This will be the 12th on the all-time list at Red River Landing. The river at both locations will remain in flood well into June.