End of Week Rain Potential & Winter Weather Preview For Next Week

A storm system weaker than the one that just exited the U.S. will move through the Southeast through Saturday, bringing Virginia a good chance for rain beginning late Friday night into Saturday. The upper level vorticity for this system is currently over the desert Southwest, as shown here:

This upper support is also pulling moisture northward from the Gulf into the southern U.S. today, creating scattered light snow and rain showers. This moisture will spread toward the Mid-Atlantic Friday, which we will notice in the form of increasing cloud-cover from the south.
I do not expect rain to move into southern Virginia until after dark Friday.
Here's a Saturday time-line of the rain for you:

As you can see, we may get some breaks in the rain during the day Saturday, so don't expect a total washout. However, we could pick up anywhere from a quarter to a half inch of rain in the area from this system.

The rest of the weekend should be dry. There has been indication in the past couple of days of our weather pattern shifting back colder next week, much in the form we've experienced most of this Winter. There is the potential for two snow events next week. The first would be a quick, light snow on Tuesday as a result of a fast-moving clipper system. The second event is highly uncertain right now, but looks like it could affect Virginia sometime between Wednesday and Friday. That storm would be a coastal low pressure system developing in the Southeast, and then hugging the coastline up to the Mid-Atlantic. As we are well aware from prior storms this Winter (and last Winter, for that matter), that low's track will significantly impact our winter weather potential in the Commonwealth. The timing of this system will likely shift in the coming days, as will our expected impacts. But we are monitoring the data and looking for that pattern shift that would set us up for another coastal winter storm. We'll provide updates here on the blog! --Carrie

Spring Preview!

Yesterday was a rare treat for us this Winter with a high temperature at Richmond International Airport of 68 degrees. It was also on the heels of a temperature roller coaster since last weekend, where we've seen high temperatures range from the upper 30s to the upper 60s:

How rare was yesterday's warm-up? Well it was one of only three days since the meteorological start of Winter (December, January and February are considered to be the Winter weather months) with a high temperature of 60 degrees or warmer. Jan 1, 2011 had a high temperature of 61 degrees, and December 1, 2010 was 67 degrees. In fact, you have to go back to just before Thanksgiving to have a warmer day than yesterday!

But after a strong cold front swept through the Commonwealth last night, we experienced an abrupt end to the sweet taste of Spring as we now return to seasonable temperatures for the rest of the week. Check out the temperatures this morning across the eastern half of the U.S. (as of 8 a.m. Eastern) behind this storm system:

The purple to light pink colors in the nation's Heartland indicate temperatures this morning for them in the single digits to below zero (where the core of the Arctic high pressure is located). Here is a closer view of the low temperatures in Oklahoma, one of the hardest hit states by the snowstorm and the Arctic air:

The highest snowfall totals in Oklahoma were in the northeast corner, where 20" of snow accumulated in Miami, for example. Notice how the most of the coldest low temperatures in the state occurred there? That is the "ideal overnight cooling" result of clear skies, ample snowpack, light winds, and dry air.


I'll have an update on our next two storm systems in my next blog entry...stay tuned!
--Carrie

Winter Storm Update & End-of-Week System Preview

The far-reaching, historic storm system that blasted the nation's heartland yesterday is aiming for the Great Lakes and New England today, with continued heavy snow and whiteout conditions at times from strong winds. Here are some of the biggest snowfall totals from this storm system so far:

You can view more snowfall totals at the Hydrometeorological Prediction Center. In the warm side of the storm, wind damage was common through the southern U.S. yesterday. You can view some of the storm reports at the Storm Prediction Center.

As of Wednesday morning, Blizzard Warnings (in red on the map) continue for parts of the Upper Midwest, with Winter Storm Warnings for most of New England:

This potent low pressure system will continue to track northeast, dumping its highest snowfall amounts just to the north of the low's center. This is the forecast snowfall from 7 a.m. Wednesday through Saturday evening:

Of course, that snow total you see in Chicago of 4.5" is what will fall on top of what already fell yesterday and overnight with blizzard conditions. Here's a breakdown of the rest of this system's life through Thursday:

Scattered rain showers will continue in central Virginia through about 10 a.m., and temperatures will soar through this afternoon as the low pressure pulls in much warmer air from the south into the Commonwealth. High temperatures will reach the 60s and low 70s!

Expect a warm and windy afternoon with winds shifting to the west as the low moves to our north and northeast. Most of central Virginia will have sustained winds in the 20-30 mph range with some higher gusts around 35 mph today, but the strongest winds in response to the low pressure system will occur in western Virginia. There is a Wind Advisory in effect from 11 a.m. through tonight for the counties highlighted in tan on the map below.

High profile vehicles traveling along I-81 today will certainly have a rough drive with these strong crosswinds.

After high temperatures this afternoon peak in the upper 60s and low 70s, the strong cold front associated with this low pressure storm system will sweep through the region after 7 p.m. Much colder air will move into central Virginia tonight, returning us to seasonable temperatures for the duration of the week.

Our next storm system will approach us from the south at the end of this week. It will not be nearly as strong as today's monster storm, but it will pull moisture from the south northward into Virginia on Friday. First, we'll notice the increase in cloud-cover from the south during the day.

Rain should begin moving into the Commonwealth late Friday evening, so most of Friday will be dry.

Rain will continue to be likely into Saturday.

At this time, it appears that the precipitation mode will be rain only for central Virginia. Here is the GFS model forecast sounding (vertical view of the atmosphere from the ground up...the right line is air temperature, the left line is dew point temperature) for Saturday morning, which clearly indicates rain (the right-slanted blue 0 degree Celsius line is the freezing line):

Even the forecast sounding by Saturday night at 7 p.m. still has surface temperatures above freezing and the rain ending:

If colder air on the backside of the system can arrive quickly enough Saturday afternoon, we may see a brief changeover to light snow, but that scenario does not appear likely right now.