Friday, February 25, 2011

Explanation Of Today's Winds

Here is a list of some of the highest gusts from Friday. You can find a full list by clicking on the following links:

http://bit.ly/giEWhA

http://bit.ly/blCNU8



Winds are driven by differences in pressure. Today we had a powerful low pressure parked off the coast of Boston. At the same time, a strong area of high pressure settled into the Upper Midwest. The entire Mid-Atlantic region was stuck in the middle of this clash.

Here are the gusts from 4 PM, when we experienced our strongest winds. Around this time our Sky Tracker camera in downtown Richmond recorded a gust of 62 mph! These winds extended all the way north into Pennsylvania and down south into North Carolina.


Our winds will quickly subside tonight as the core of the high pressure nudges closer to our area and the low tracks into the North Atlantic.

Strong Winds, Rain, & T-Storms Friday

Strong winds are occurring today in the Commonwealth as a potent low pressure storm system sweeps through our region. High Wind Warnings (yellow shade on map) and Wind Advisories (tan shade on map) are posted through 8PM in the area. Sustained winds most of the day will remain in the 25-35 mph range!

Not only will it be windy today, but after our first round of morning rain we could get thunderstorms, some of which could be severe from mid-day through 4PM (damaging straight-line winds are the primary threat). There is a slight risk area today in yellow for part of central Virginia (highlighted in yellow below), where isolated, brief tornadoes may also occur in addition to the straight-line damaging wind threat that exists for most of central Virginia.

Here's a timeline of both the rain and the winds for the rest of today:

And here are the expected sustained winds at that same time (higher gusts will be occurring):

As the cold front nears the mountains in western Virginia, winds will be at their strongest from the southwest, bringing in a surge of moisture and warmth from the south to serve as fuel for thunderstorm development. In addition, the surface cold front will serve as a forcing mechanism for thunderstorms to develop, especially as we get breaks in the clouds mid-day into early this afternoon allowing for some heating and instability to form.

Winds mid-day will be sustained at 25-35 mph, with gusts as high as 45 mph.

Severe threat will continue through mid-afternoon as the strong cold front rushes through central Virginia. The primary threat out of any storms that can form ahead of the front will be damaging wind gusts and downbursts (70mph+).

As the front passes through the heart of central Virginia mid-afternoon, winds will still be running 25-35 mph with gusts to 45-50 mph:

Our severe threat will end by 4PM as the front reaches southeast Virginia, forcing the moisture and instability out to sea. Much cooler, drier air will surge into the region behind the front, and you will notice the change in humidity and temperatures this evening.

Even after the cold front passes, it will take until closer to midnight for winds to subside below 10 mph. If you have evening plans, these are your expected sustained winds at 7PM:

It looks like we could get another quarter of an inch in central Virginia today from the rounds of rain, but those of you who get the possible t-storms, you could get locally higher amounts of rainfall! We will be closely monitoring the severe threat today and provide updates both on air and on-line. Stay with CBS 6, we'll keep you ahead of the storm. --Carrie Rose--