Big Wind Contest ...next 48 hours

[Bill O]

Looks like yesterday (with an average wind speed of 104.5 mph) was the windiest day since Dec 4, 1980, when the average wind for the day was 116.8 mph. Their peak gust that day was 178mph.

I can always count on you to dig up that data. Do you mind double checking that? That is pretty big news if that verifies. The windiest day since the windiest day in the new building.

[Steve M]

I must say for a while there last night I thought I had it but one gust put me out of the running.

[Brad]

Um, hold on there. According to the MWO website the peak wind gust was 149mph. We measure wind speed to the nearest whole mile per hour, and even that is pushing it.

It looks like a tie between Jim and I.

Well, you could say that it is a tie using that level of precision. But, we all would know you were off 3 times the amount JimS was off.

[Bill O]

But, we all would know you were off 3 times the amount JimS was off.

Three times off...that is bad.

The official peak gust is still 149mph.

[treant985]

I can always count on you to dig up that data. Do you mind double checking that? That is pretty big news if that verifies. The windiest day since the windiest day in the new building.

The info came from Thomas Seidel, a Staff Scientist at MWO, who went through the staff database for 1935-2004 data and found all cases of mean wind of 100+ mph for a given day (midnight to midnight). I also have copies of the monthly reports that MWO sends to the NCDC in Asheville, so that let me check the info since 2004.

Here are the windiest days since 1940, thanks to Mr. Seidel:

12/04/1980: 116.8 mph
01/02/1943: 108.0 mph
03/21/2008: 104.5 mph
12/26/2000: 102.8 mph
04/05/1995: 102.0 mph
01/16/2006: 101.9 mph
04/03/1970: 101.4 mph
11/13/1990: 101.0 mph
01/02/1969: 100.0 mph
01/09/1985: 100.0 mph

...there have been 42 days since 1940 where MWO had a peak wind of 150+ MPH.

[bclark]

since Dec 4, 1980, when the average wind for the day was 116.8 mph. Their peak gust that day was 178mph.

Actually, the Hays Chart for that day reads a peak wind gust of 182 mph. I suppose I shouldn't say the chart "reads" that speed because a speed of 182 is off the chart on the Hays. These days, gusts over 140 are recorded on the Barton Chart...I'm not sure how they recorded gusts over 140 in 1980. The peak gust of 182 mph is simply written on the Hays chart. That's one of the night observer duties.

We have that Hays Chart on display on the Weather Wall because it stands not only as the windiest day in the Sherman Adams Building, but also as the second highest wind gust MWO has recorded, next to the "Big Wind".

Was the data you have for that day from Tom S., or from NCDC?? I'm curious why we have two different peak wind gusts on record for that day.

[edog2007]

Wow,thats just crazy wind.Time to fly a kite.

[treant985]

Actually, the Hays Chart for that day reads a peak wind gust of 182 mph. I suppose I shouldn't say the chart "reads" that speed because a speed of 182 is off the chart on the Hays. These days, gusts over 140 are recorded on the Barton Chart...I'm not sure how they recorded gusts over 140 in 1980. The peak gust of 182 mph is simply written on the Hays chart. That's one of the night observer duties.

We have that Hays Chart on display on the Weather Wall because it stands not only as the windiest day in the Sherman Adams Building, but also as the second highest wind gust MWO has recorded, next to the "Big Wind".

Was the data you have for that day from Tom S., or from NCDC?? I'm curious why we have two different peak wind gusts on record for that day.

Tom also sent me a list of days with 150+ mph peak gusts, and it shows 178 for that 12/4/1980. Also, I'm not able to access them right now, but I do believe that NCDC showed the same thing, which makes sense since they just have photocopies of what MWO sent to them.

Also, the page on this site that lists records shows 178 as the record wind for December: http://www.mountwashington.org/weather/normals.php .

I do recall that Tom and I noticed a few places where the NCDC photocopies didn't match what Tom's database showed. A few of them were chalked up to where the observer put the observation in knots in one spot, and in MPH in another. But there were others that had slight differences that we couldn't explain...

[bclark]

Tom also sent me a list of days with 150+ mph peak gusts, and it shows 178 for that 12/4/1980. Also, I'm not able to access them right now, but I do believe that NCDC showed the same thing, which makes sense since they just have photocopies of what MWO sent to them.

Also, the page on this site that lists records shows 178 as the record wind for December: http://www.mountwashington.org/weather/normals.php .

Very interesting. I'll have to look into this during my next shift and find out which one is correct. Then we need to at least make sure the correct peak gust is displayed in the places we have the power to change. Obviously, the NCDC records are not one of those things.

I've always been under the impression that 182 was correct since I see it on the Hays chart and tell every tour that I give that it was 182 on that day.

A few of them were chalked up to where the observer put the observation in knots in one spot, and in MPH in another. But there were others that had slight differences that we couldn't explain..

I don't doubt that has caused some confusion at times, however there is no way that is the case regarding December 4, 1980. 178 knots = 205 mph.

[Neil]

Thought I'd add my two cents since I know a thing or two about the Hays chart...

1.) The hays chart is calibrated for an assumed standard pressure and temperature. Namely the average barometric pressure and temperature for MWO. Since the device works off a differential pressure transducer this means that large temperature or pressure variations away from the normal will have a noticeable impact on the recorded windspeed. In order to come up with the actual speed a relatively straightforward calculation needs to be performed using the displacement measured on the chart, the air temperature, and the actual pressure. Technically moisture content of the air could be considered as well but especially at low temperatures it has a rather neglible impact.

2.) The above discussion is why there is a discrepency between what is written on the hays chart and what is officially recorded on the obseravtory F6 and thus with the NCDC as well. After correcting for temp/pressure, the true gust is 178 for Dec 4 1980.

3.) As far as the Hays chart being able to record winds up to 180ish range... First of all it couldn't, the Dec 4th chart has the peaks well off the page. There was a second hays chart, calibrated for 15 inches of water instead of 10". This was used similarly to the way the Barton is currently used. Furtheremore the Hays chart that currently reads to around 145 mph is no longer a 0-10" chart. It was damaged in the late 1990s and then recalibrated to compensate for the damage. It is now only good up to around 8 or 9 inchs of displaced water column. This explains why the charts that are from the big wind summer wind of 1996 could be record peaks above 150 mph on the Hays while yesterdays 148.5 gust topped the chart.

4.) Unless things have changed since I left, the 148.5 was not measured with the Hays at all. It was measured with a second device, the setra pressure transducer which is a digital device that ranges from 0-30 inches of water displacement. It is an excellent device with high precision, accuracy and response time. It was calibrated at the factory in the summer of 2006 and should be considered the gold standard. The charts are excellent back up however. Also unless things have changed with automation in the data base the setra wind speed would still need to be corrected for pressure and temperature. Could make a difference of a few mph.

Other than that, glad to see the summit getting some good winds.
And Jim, glad to see you've still got a knack for nailing the wind speeds.

Brian, thats probably my fault for never explaining that the Hays chart for 1980 was actually a bit off. It was just easier to tell tours the number on the chart than to launch into the above discussion.

-Neil