Sunday, January 23, 2011

Tuesday/Wednesday Update & Timeline

Precip will not start for another two days, so we can still see some shifts in the forecast. Generally speaking, this storm has been more "well-behaved" than previous storms. The computer data has been very consistent, so I haven't changed much from yesterday. Regardless, I encourage you to keep a close eye to the forecast tomorrow and Tuesday for any adjustments. Below you will find a timeline of what to expect with this storm.

1PM to 7PM Tuesday
Most of Tuesday looks cloudy and dry, though an isolated shower could sneak into Southern VA during this time.

7PM Tuesday to 1AM Wednesday
Precip will move into the area from the south at this time. It could briefly start as a wintry mix, especially along and west of I-95. As you can see below, temps will be above freezing in central VA, so I'm not expecting major problems on the roads.

1AM to 7AM Wednesday
Scattered rain showers likely across Central VA with a wintry mix still possible in Northern and Western VA. Accumulations will start in far Southwest VA.

7AM to 1PM
Periods of rain still likely in Central VA. Accumulations start building in Northern and Western VA.

1PM to 7PM Wednesday
Rain will briefly change over to wet snow in Central VA. With temps in the mid 30s, most snow will accumulate on grassy surfaces or anything detached from the ground (if at all). Accumulating snows will taper in Western and Northern VA.

Here is a map of vorticity, or spin, in the atmosphere for Wednesday afternoon. The red blob indicates a very potent upper-level storm system. These types of storms are notorious for creating a quick burst of snow, especially north of the vort max (red blob). The track of this vort max, along with surface temperatures, will be the keys to this forecast.

This is an early look at the accumulation potential. If anything will change with this forecast, it will be this map below. Be sure to check back tomorrow and Tuesday to get the very latest updates!