Friday, September 17, 2010

Drought Likely Through Christmas

The severe drought conditions plaguing central Virginia right now will likely persist until at least Christmas. There has been no change to the drought conditions over the past week, as indicated by our weekly update map here:

But the big concern is when will this drought end? Because of a strengthening La NiƱa in the equatorial Pacific Ocean, expected rainfall through the end of the year in Virginia will likely not be enough to pull us out of the deep rainfall deficit. As of today, Richmond International Airport is 9.35" below average for our year-to-date precipitation. Most of this deficit is as a result of missing Summer rains, which were held off by persistent high pressure ridges inhibiting storm tracks from reaching us, and also limiting afternoon and evening storm development because excessive heat accelerated drying. July is usually our wettest month of the year, picking up 4.67". This year, we accumulated just 1.19". Our precipitation tally stands at 22.96" this year of liquid precipitation (including the melt-down from winter snow). On average, Richmond has an annual rainfall of 43.91" (1971-2000 normals). If we don't get another drop of rain the rest of this year it would be our second driest year on record. Here's the Top Ten Driest:

1.) 1941 22.91"
2.) 1876 27.65"
3.) 1970 28.29"
4.) 1965 29.76"
5.) 1921 30.59"
6.) 1930 31.26
7.) 1925 31.42"
8.) 1954 31.45"
9.) 2001 31.52"
10.)1877 31.71"

If rainfall is scant through Christmas, it's feasible, if not likely, this will be one of our driest years on record.

You can read a full summary of the drought impacts in our region here. You can also learn more about the long-range drought outlook forecast here.