Hurricane Season 2009 Ends

November 30th marks the official end of the 2009 Atlantic Hurricane Season, which began June 1st. Here's a recap of this year's storms:

Tropical Depression One
Tropical Storm Ana
Hurricane Bill (max Category: 4)
Tropical Storm Claudette
Tropical Storm Danny
Tropical Storm Erika
Hurricane Fred (max Category: 3)
Tropical Depression Eight
Tropical Storm Grace
Tropical Storm Henri
Hurricane Ida (max Category: 2)

That's nine named storms, three of which became hurricanes, two of which were major hurricanes. An "average" tropical season has 10.1 named storms, 5.9 hurricanes, with 2.5 of those becoming major hurricanes at Category 3 strength or greater.

So that means 2009 was slightly below-average for the number of named storms, with only half the average number of hurricanes. Still, of those few hurricanes that did form this year, two of them became major, which is about average.

We've talked about this previously on the blog, but El Nino is possibly one of the factors impacting the reduced number of tropical cyclones able to strengthen to hurricane status. The El Nino in the equatorial Pacific has been strengthening through the Summer and Fall months, which alters the upper-level wind patterns globally. This led to more wind shear (different wind speeds at different heights and directions) in the Atlantic, Caribbean, and Gulf, which disrupted cyclone organization. Shear prevents cyclones from strengthening uninhibited. Instead, the shear acts to "rip apart" the cyclone circulations, keeping most of this year's storms below hurricane status.

You can get the weekly update (Mondays) on El Nino here.

Tracking Two Storm Systems

Two storm systems will bring an opportunity for rain to Central Virginia over the next week. The first will be a chance for showers (a quarter-inch of rain or less) as a cold front passes through the state on Monday. As of Saturday night, that front is moving through the Midwest and Plains. (See map below...click to enlarge.)

A second system will bring us another opportunity for rain Wednesday. Our Wednesday storm system is currently over the Southwest U.S. and is now cut-off from the upper flow that will steer the Midwest system toward us Monday. The Southwest low will gradually make eastward progress early this week, passing through the Southeast U.S. toward Virginia by Wednesday. This system looks like it will be the stronger of the two, with very gusty winds and heavy rain (1"-3") possible from Wednesday afternoon through Thursday morning. Here is a snapshot of what the system will look like around 1 a.m. Thursday:

See that tight pressure gradient over the Commonwealth? That should lead to wind gusts around 35-40mph from late Wednesday into Thursday morning.

Space Station Viewing Tonight

A great International Space Station viewing will occur tonight in Richmond from about 5:29-5:34 p.m. Just look Northwest to Southeast as the ISS passes directly overhead. Look for a bright white dot moving smoothly across the sky (at about 17,227 mph!). The ISS orbits the Earth 15.7 times per day at an altitude between 173 mi and 286 mi.

A few clouds may occasionally obscure your view of the Space Station, but skies will generally be clear enough to spot the light this evening. If you want to find the specific viewing opportunity for your location, click here.