Tuesday, March 15, 2011

Tornado Preparedness Day

Today was Tornado Preparedness Day in Virginia, where tens of thousands of people practiced their tornado safety plan. A test tornado warning was issued by the National Weather Service office in Wakefield, Virginia, at 9:45 A.M. Here are a couple of quick facts about tornadoes in the Commonwealth. The average number of tornadoes per year in Virginia is 10, with 2008 being an exceptionally active year with 39 tornadoes. The number of tornadoes per 10,000 square miles is displayed for the whole U.S. in the next graphic. While Virginia typically doesn't see many tornadoes on an average year, there will be years (like 2008) that will be very active. It's also important to remember that tornadoes have occurred in every month of the year, so have a plan, and always be ready for when severe weather moves through central Virginia.

Sunday, March 13, 2011

Winter 2010-2011 Recap: Cool & Dry

Wintry weather can sometimes randomly pop up in late March and early April. In fact, the latest snowfall in Richmond recorded history was on April 28, 1898, where there was 2" of snow. Regardless, for the most part, winter is over. So let's look at some of the stats.

TEMPERATURE
December was the 7th coldest in history (link http://www.erh.noaa.gov/er/akq/climate/special/RIC_AVE_T.pdf). The cold weather persisted into the first half of January, then the overall pattern changed. Temperatures generally remained above normal for the rest of winter. The map below shows that the entire Southeast U.S. experienced temperatures that were 2 to 6 degrees above normal for the month of February.



If you combine all months together, the overall average temperature for this winter was slightly below normal.


PRECIPITATION
There is no doubt about it: this winter was dry. We were roughly 2 to 4" below average across the entire state. Interestingly, we received 10.8" of snow, which is only slightly below the average of 11.9". Most of the snow fell in December and early January before the pattern change. You can see on the map below that we weren't the only ones dealing with dry conditions. It was even worse in Louisiana, Mississippi and Alabama.

Friday, March 11, 2011

Update On The James River

Rivers and stream are running very high this morning after yesterday's rain. Notice all the black and blue dots on the map below - they indicate rivers and stream levels which are much above normal. You can find an interactive version of this map at the following link:

http://waterwatch.usgs.gov/new/?m=real&r=va


The James River is expected to crest at 14.8 feet in Westham tomorrow morning. This is high enough to produce some minor flooding in low lying areas near the river. The James should drop below flood stage by early Sunday afternoon. Use extra caution if you plan to be anywhere near the river this weekend!