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Posted at 11:45 AM ET, 03/ 3/2011

Was this winter really that windy in Washington?

By Don Lipman

Answer is surprising

winter-2011-winds.jpg
Winds at Reagan National (DCA), Dulles (IAD), and BWI airports compared to average in December, January, and February.

I don't know about you, but I thought that this past (meteorological) winter, although not particularly snowy around here, was brutally windy on many days, perhaps more so than in many years. The basis for Mother Nature's rampage was well described by Jason Samenow in a recent post. But perceptions are often wrong, particular when it comes to the weather, so I decided to do a little research. Was I right or am I just getting older so that I can't take those "hold-your-hat-down-days" any more?

According to the National Climatic Data Center (NCDC), the average December wind speed at Reagan National Airport (DCA), for example, is 9.4 mph. As depicted in the graphs above the National Weather Service (NWS) reports that the December 2010 average was 10.8 mph. There were 9 days with average wind speeds of 15 mph or more and one with an average of 20 mph or more (December 27th, the day after the "Boxing Day" blizzard that clobbered the Northeast and gave us little more than flurries). There were 25 days with peak gusts of 20 mph or more and 19 with peak gusts of 25 mph or more. The peak gust for the entire month was 55 mph on the 27th.

So far so good; December was about 15% windier than normal at DCA by my calculations, at least based on average wind speeds. And as you can see above, the same held true at the other two major reporting stations, with Dulles International Airport (IAD) showing the greatest departure--a whopping 39% above average. (I try to avoid the word "normal.") The December 2010 average wind speed at Baltimore-Washington International Airport (BWI barely exceeded the long-term average, however.

During January, the atmosphere seemed to calm down--or maybe "reload" is the better word. Again, according to the NCDC, the average January wind speed at DCA is 10.0 mph but the NWS reports that in January 2011, DCA's average was only 8.4 mph. There was only one day (the 9th) with an average wind speed of 15 mph or more, none with an average of 20 mph or more. However, there were 23 days with peak gusts of 20 mph or more and 14 with 25 mph or more. The month's peak gust was 41 mph, on both the 12th and the 26th.

Despite some gusty days, January, then, was considerably more tranquil in these parts than December was, with DCA about 16% less windy than average and the other reporting stations showing similar departures.

February reverted to much more turbulent weather, with frequent bouts of tropical storm force winds, but for different reasons than in December. The average February wind speed at DCA is 10.3 mph, third highest of the year, but surprisingly, February 2011 was below average in two of the three reporting stations and barely above average at Dulles (IAD) with a tentative average of 8.7 mph vs the "normal" of 8.6 mph. There were only four days with average wind speeds of 15 mph or more and just one--the 19th--with an average of 20 mph or more.

Despite the low average wind speeds, February's winds did show considerable muscle. Peak wind gusts exceeded 20 mph on 21 days and exceeded 25 mph on 17 days, almost as many as December, perceived by many as the windiest month of the entire winter. Perhaps a more revealing statistic is that February had 6 days with wind gusts of 40 mph or more (December had only four) and four days with gusts exceeding 45 mph (December had only three). Even January, the least windy month this winter, on average, had six days with gusts exceeding 40 mph. February's peak gust was 58 mph on the 25th.

All in all, then, was it a windier (meteorological) winter than average? Statistically, no, since two of the three months had average wind speeds below normal (at least for DCA and BWI). Personally, I would say yes, based on the relatively high number of days with winds approaching or exceeding warning criteria. What do you think?

----

While on the subject of winds, following are a couple of historical notes, particularly for you weather trivia buffs, about how winds are (and used to be) represented and described:

Although on today's weather maps, a wind pennant or barb faces into the direction from which the wind is blowing (so that the barb faces east when there's an east wind), I knew it wasn't always that way. Verifying this was a little tricky, but I did find an obscure phrase indicating that over 100 years ago, wind barbs faced downwind. Still not satisfied, I looked at the weather map for March 12, 1888, when the famous "Blizzard of '88" was roaring in the Northeast. Sure enough, the wind barbs were generally facing anywhere between southwest (a northeast wind) and southeast (a northwest wind).

Later I found that it was not over 100 years ago that this change occurred because U.S. weather maps as late as 1940 still showed wind barbs facing downwind. I believe, then, that the change to the current convention occurred on August 1, 1941, when many aspects of the weather map station model were all changed at the same time.

Aside from the way winds are depicted differently on weather maps today is the way changing winds are described today. Not long ago, when winds shifted from the east, to the northeast, and finally to the northwest, such as when a storm center passes by to the east, it was said that the winds were "backing," a somewhat archaic term today. Furthermore, if a storm passed by to the west causing winds to change, say, from a southeast to a southwest direction, we were said to have "veering" winds, also archaic today. Currently, weathercasters seem just to prefer the terms "changing" or "shifting."

What about the strongest wind ever recorded by a surface anemometer? It was long regarded as 231 mph at the Mt. Washington, New Hampshire weather station on April 12, 1934. Over a year ago, the World Meteorological Organization claimed that this record had been broken in 1996 during an Australian cyclone (a hurricane). But now, it appears that that claim has been discredited.

And last but not least, the strongest winds in our entire solar system are thought to be on the planet Neptune, where NASA has recorded winds over 1500 mph. That would definitely be a "hold-your-hat-down-day!"

By Don Lipman  | March 3, 2011; 11:45 AM ET
Categories:  Latest, Lipman, Local Climate, Wind  
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Comments

Thanks so much for this! I was one of the commenters who inquired a couple days ago. Really appreciate this breakdown. Personally, I feel it was WAY windier than any other winter I've experienced in this area (going on 9 yrs).

Posted by: rhingo | March 3, 2011 12:10 PM | Report abuse

Couple weeks ago I did a very crude comparison of the ENSO data to the wind (Atlanta was the closest city I had). It looked to me that the most wind came in ENSO neutral, not La Nina or El Nino. But there were exceptions, not a clear cut conclusion.

Posted by: eric654 | March 3, 2011 12:41 PM | Report abuse

Compared to previous winters, there weren't necessarily more windy days, but there seemed to be more days when the winds hit gale force with gusts well into the "tropical storm" range of 39+ mph. On the windiest day it seems that Reagan hit a peak gust of 58 mph, same as the peak gust recorded during the remnants of Hurricane Isabel. The difference: Isabel's gust came from the southeast and caused more damage as trees here can better withstand wind gusts from westerly quadrants where the prevailing high winds around here generally come.

In addition the February gusts seemed to resemble the peak gusts which generally arrive here with storms during March. Could global warming be moving the "March winds" a month ahead into February??? We'll have to see whether March continues the pattern or whether typical April weather starts arriving a month ahead of schedule...

Posted by: Bombo47jea | March 3, 2011 1:05 PM | Report abuse

The February data is pretty shocking. It was feast or famine with the wind I suppose.

Posted by: Jason-CapitalWeatherGang | March 3, 2011 1:25 PM | Report abuse

"Backing" and "veering" winds DO retain important meteorological significance, especially in Northern Hemisphere temperate latitudes such as ours.

Often if the wind "backs" [in a counter clockwise direction] it's a sign of impending rain or snow, particularly if the original wind direction is westerly or southwesterly. Backing winds around here are typical of the offshore passage of a nor'easter or hurricane.

Similarly a "veering" [clockwise-shifting] wind, particularly when the original wind direction is from a southerly quadrant, may herald the onset of fair weather. Old sailors and farmers tended to use the weather glass [barometer] in connection with the wind-shift tendency and changes in sky conditions to forecast future weather events in the days before on-camera meteorologists started showing fancy jet-stream and computer model charts on the 6:15 and 10:15 weather reports.

BTW, in the Southern Hemisphere the wind-shift tendency patterns are reversed when forecasting while using wind-shift tendencies. this is because Southern Hemisphere lows rotate clockwise while highs rotate counter-clockwise.

Posted by: Bombo47jea | March 3, 2011 1:29 PM | Report abuse

Average winds, like average temperature, aren't very helpful for describing our experience of wind and temperature (they might be helpful for tracking data, of course). After all, it isn't the average wind speed that blows down that tree in my yard, but strong wind gusts.

With what felt like a higher than normal number of days with significant gusts, I'd say that it was a windier winter - we had more days of high wind, even if over the entire winter the average wind speed wasn't any higher than normal.

Do you have any comparative data on # of days per month/winter with gusts over 40 mph? That would be the more useful metric, it seems to me.

Posted by: chrisduckworth | March 3, 2011 2:03 PM | Report abuse

CapWx Gang (this comment is more in reply to Wes's post earlier)

Forecasting postmortems have always been one of those rare features in the meteorology community that CapWx has offered. Why? Because CapWx is willing to admit a mistake, unlike TV mets. That quality is endearing.

I have read this site daily since the capitalweather.com days. I first came to CapWx to see if a snowstorm would close my high school (circa 2004). Then to see if my undergrad school would close for snow. Then grad school. Now OPM!

Keep up the great work. Seven years down, and I hope at least seven more to go! :)

Posted by: JTF- | March 3, 2011 2:05 PM | Report abuse

Seems like the wind blows when I plan on fishing. Although it wasn't 2 bad yesterday, & 2morrow looks good from a light wind stand point. Striper fishing is slowing down at the 301 Bridge, so I need 2 get out as much as possible the next 2 weeks.

Posted by: VaTechBob | March 3, 2011 2:29 PM | Report abuse

JTF - good to see you; thanks as always for following! Glad you like our postmortem evaluations. I think Don really gathered the data together well and presented it very thoroughly regarding winds this past Winter. I am a fan of proving or disproving meteo-psychological perceptions!

VaTechBob - good luck with all the fishing. Always will look for you when going to/from Popes Creek MD, across the bridge there..

Posted by: Camden-CapitalWeatherGang | March 3, 2011 3:11 PM | Report abuse

interesting discussion about wind direction conventions. it has always seemed totally crazy to me to call a wind blowing from west to east a "west" wind. i mean sure it's coming FROM the west, but it's going to the east. one doesn't call the interstate highway coming from rt. 81 to the beltway 66 "west" - even though it's coming FROM the west. why would you have the wind arrows or "barbs" pointing into the wind? again, that seems totally crazy.

and, the results of this wind analysis seem very counter-intuitive. jan and feb (and of course december) seemed very windy to me too. i wonder if it's a product of when during the day the winds where blowing.

Posted by: walter-in-fallschurch | March 3, 2011 3:19 PM | Report abuse

This seems to be a rather windy place on the whole. There are of course issues with averages but that's how the NWS keeps records. I would think once you get into the more extreme peak gust categories -- i.e., 40+/50+ -- you might see this winter excel a bit more than the average shows. Unfortunately wind data is harder to get historical info on than temps/precip.

Posted by: Ian-CapitalWeatherGang | March 3, 2011 3:56 PM | Report abuse

chrisduckworth: I believe that info is included: Dec had 4 days with gusts over 40 mph, Jan had 6 and Feb had 6.

Posted by: Weatherguy | March 3, 2011 3:57 PM | Report abuse

This is an interesting post, enjoyed it. I travel between NYC and DC a lot, NY seems to be a breezy city overall (buildings, the waterways perhaps?). Also, the temperature in the winter there 'feels' cooler, a 40 there I dress for differently than when I'm here at home in DC.

Is there a site to find average wind speeds of cities?

Posted by: nykr29 | March 3, 2011 4:21 PM | Report abuse

Take that back, you all listed it. Indeed, NY is much windier than others on average. Food for thought.

Posted by: nykr29 | March 3, 2011 4:24 PM | Report abuse

Very enjoyable article!

To amplify chrisduckworth's post, statistically it can be a windier winter without a different average. It just depends on your choice of metric, and your metric doesn't have to be an average. The world of statistics is much bigger than that.

You are hinting at another metric when you talk about the number of days the highest gust exceeded 25 mph. When you say there are a greater number of windier days than usual, you're getting into a probability distribution on top wind speeds and pointing out the right (windier) tail is thicker than usual. You can also use order statistics on the highest wind gust. Find the highest wind gust each day winter 2010-2011 and do the same for 2009-2010. Arrange them for each year from smallest to largest. Do they look different? A good eye can be a good first guess.

I don't want to make extra work for anybody, just point out when we're talking about extremes, average doesn't get you that far.

Posted by: kperl | March 3, 2011 6:19 PM | Report abuse

The figures are misleading. Average for the month takes into account ALL days of the month. When people say "It's been more windy this winter than usual" people are saying we had more high wind warnings and much stronger winds than usual, which is true. You are comparing apples and oranges by counting all the days. Using your logic if we had a day with 200 mph winds destroying all of the Washington area but all the other days of the month were calm would you say "You know, it really hasn't been that windy this month. We are below average".

Posted by: rwalker66 | March 3, 2011 6:23 PM | Report abuse

Fascinating analysis. As mentioned by others, the mean wind speed is only one statistical method to compare year-to-year and month-to-month data, but I feel that the number of high-wind days (highest gusts over 30 mph or so) might be a better way to rank a month's "windiness."

Posted by: marklandterrapins | March 3, 2011 10:39 PM | Report abuse

rwalker66: Sorry I didn't get back to you--didn't see your comment. But I have recognized the difference between classifying a month as windy based on averages vs calling a month windy based on gustiness on certain days.

The fact is that DESPITE January's calmer winds, for example, there were quite a few days with high gusts, which I cited. The NWS averages monthly wind speeds based on a summary of each day's average. They don't average peak wind gusts either as an average over the days they occurred or as an average over the whole month, as a rule.

Posted by: Don-Capital Weather Gang | March 4, 2011 2:49 PM | Report abuse

The comments to this entry are closed.

 
 
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