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Posted at 10:05 AM ET, 02/24/2011

High wind watch for the region yet again

By Jason Samenow
02-24-winds.gif
The NAM model projects winds of 30-40 knots (or 35-45 mph) across the region Friday at 4 p.m. Source: Penn State ewall.

Since December, the winds around the D.C. metro region have seemed relentless - and more persistently disruptive than I can ever remember. Less than a week after our last significant wind event, the National Weather Service has issued a high wind watch for Friday for between 11 a.m. and 7 p.m. The watch includes most of the metro region, but excludes some the southern areas including southern Fauquier, Stafford, Charles, Calvert and St. Mary's counties. But gusty winds to 50 mph are still possible in areas outside the watch.

Here are some of the key points from the watch:

* Sustained winds of between 20 to 30 mph, with gusts to 50 to 60 mph are likely

* Possible impacts: Power outages and downed trees and large branches.

* Recommended action: Ensure loose objects are secured or brought inside

The worst of the winds are likely in the afternoon. These winds may accompany a possible line of thundershowers when a front comes through tomorrow midday and/or may follow the front as the air dries out and higher pressure builds in.

Keep reading for information on why it's been so windy...

Unlike the last Saturday's wind event, the fire threat will be significantly lower due to the 0.5-1" of rain anticipated before and during the possible high wind. The air will dry rapidly behind the front tomorrow afternoon, but the vegetation/brush will have much higher water content.

So why has it been so windy?

In December and January, the wind was related to the weather patterns associated with the negative phase of the Arctic oscillation (AO). In that pattern, Arctic airmass after Arctic airmass originating from northern Canada dove southeast, driving windy cold fronts through the region. Low pressure often developed along these fronts over the ocean and difference between lows developing to our northeast and Arctic high pressure systems in their wake kept the wind going for days.

During the second half of February, even though the AO has gone into its positive or neutral phase, fast moving energetic weather systems along the northern jet stream - characteristic of both a La Nina pattern and the early spring season (often times March, when cold and warm air masses collide) - have generated less persistent but more intense winds - like we'll see tomorrow and saw last week.

The pattern into next week also seems to be conducive to short-lived high wind events, with some potential for another windy period next Monday.

By Jason Samenow  | February 24, 2011; 10:05 AM ET
Categories:  Wind  
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Next: This winter has tested our gardens

Comments

It's Blowmageddon 2: Blow Harder!

Posted by: marklandterrapins | February 24, 2011 10:11 AM | Report abuse

As a regular outdoor runner, this winter seemed to be one of the most frequently below freezing and/or windiest that I can remember (and last year, the snowiest!). Do meteorologists track wind measurements like they do temps and precipitation, so as to measure this months-long pattern against seasonal averages?

Posted by: novajeffc | February 24, 2011 10:26 AM | Report abuse

lol @ "Blowmageddon" ....

Great presentation this morning at ICF on Climate Change. Speaker was Mary Glackin, Deputy Under-Secretary at NOAA, and she covered a wide range of issues in managing climate change planning in gov.

Some discussion of wx models - she doesn't have a favorite, as the agcy likes to use the ensemble, and synthesize a result. More discussion on drought, but focus was on rising sea levels and impact in low-lying metros, and on security aspects for orgs like the military.

Posted by: ennepe68 | February 24, 2011 10:35 AM | Report abuse

In all seriousness, I have also wondered why we have seemingly experienced more high wind events this winter than usual (especially December, which may have been the windiest month I can ever recall ... wonder if there is a way to confirm monthly wind records). Thank you for the explanation about the difference between the early-winter AO-created wind events, and the recent La Nina events. Fascinating stuff...

Posted by: marklandterrapins | February 24, 2011 10:52 AM | Report abuse

Getting mighty tired of all these high-wind episodes--this is the fourth or fifth time since winter began--hope it doesn't continue through March and into April! Something else to blame on "much-unneeded rain".

Last time I didn't have any power outages--hope we're lucky this time.

Posted by: Bombo47jea | February 24, 2011 11:10 AM | Report abuse

I'm pretty sure there aren't any more "loose objects" left out there for the wind to play with.... but thanks for the reminder.

Posted by: FIREDRAGON47 | February 24, 2011 11:29 AM | Report abuse

Quick! Somebody get ahold of Al Gore and get the voodoo explanation of what's going on. The weather spell didn't work because there weren't enough toads or newts in the witch's brew perhaps?

Posted by: flintston | February 24, 2011 11:31 AM | Report abuse

The reason why we have had numerous high-wind events this winter is fairly simple. We've had a lot of low-pressure systems track across the central and eastern part of the country, a number of which rapidly deepened (central-pressure got lower) as they moved away from us. That, coupled with strong Arctic high-pressure systems moving down from Canada, created strong differences in the pressure-gradients (closely-spaced iso-barometric lines)....hence the strong winds. Yet another scenario like this is going to set up tomorrow....and possibly Monday.

Posted by: MMCarhelp | February 24, 2011 1:40 PM | Report abuse

It's interesting that NWS just (l:41 p.m.) knocked it down to a Wind Advisory instead of a High Wind Watch. ABC7 is still saying this:

"Looking at some of our model guidance for tomorrow, winds are forecast to be around 90 m.p.h. only 5000 feet off the ground! That doesn't occur very often."

... which seems pretty serious. I'm wondering if the High Wind Watch will be reinstated.

Does CWG have any thoughts on this?

Posted by: tinkerbelle | February 24, 2011 2:12 PM | Report abuse

The link from your main page to this post said "Why so much wind?" -- I'd love to hear your ideas on this.

Posted by: mattandeliz | February 24, 2011 6:58 PM | Report abuse

oops, after I posted my comment it expanded to show past the break!

Posted by: mattandeliz | February 24, 2011 7:01 PM | Report abuse

In Stafford at my house last weekend the power went out and almost every shingle is off my house and now its freezing cold at night. There was a high wind warning. Now in stafford county there is ANOTHER high wind warning. I wish I had one of those generators.

Posted by: andrewjohnsonlevine | February 24, 2011 9:03 PM | Report abuse

The comments to this entry are closed.

 
 
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