Author Topic: Freak Wind Storm  (Read 778 times)

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Offline ocala

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Freak Wind Storm
« on: May 11, 2017, 03:00:06 PM »
I was visiting my brother last week in Rutland, Vermont which is in the south central part of the state. It was a cool  rainy day with just stratiform rain moving through. No big storms on the radar. About 5PM  the wind started to pick up. Slowly the gusts started to build but nothing out of the ordinary. Then the gusts got really strong and trees started snapping.
About that time my brother got a phone call that some wire fencing he put up to protect apple tree  saplings on another property were blown out into the road. We all hoped in the car to go over there. When we got there the winds were at their peak. Several reports of 74mph were reported. Since we were in an open field we were relatively safe from flying debris. I have to say though I was really enjoying it. :-) I guessed we experienced winds in the 50 -55 mph range. The sound of that wind roaring through the trees and the trees snapping was really cool. I just kind of stood there in awe. The event lasted about 25 minutes.
Nobody got hurt but many trees and power lines were down and the power company had to shut off power to the whole area because of so many downed wires. Made for some strange bedfellows that night as most people couldn't make it home because so many roads were blocked.
I don't know much about mountain weather but I saw something about down sloping winds being the culprit. I emailed the Burlington, Vermont NWS office to hear their reasoning behind it.
It was a great way to start vacation though. :grin:   

Offline MonumentHillWeather

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Re: Freak Wind Storm
« Reply #1 on: May 11, 2017, 04:40:33 PM »
We see similar events happen here in western Maine, but they are pretty rare and only usually happen during the winter months when there is already a strong NW flow in place. I heard about this event that happened! Very neat to hear your experience with it! What's neat is about 12 hours later we saw a similar event here in Maine, but by then winds were only topping out around 40MPH.

Very neat for sure!
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Online Aardvark

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Re: Freak Wind Storm
« Reply #2 on: May 11, 2017, 06:16:08 PM »
last summer, I was in Cornwall Vermont and we had a sudden microburst with straight line wind, didn't last long but thing did blow around and a table was damaged outside.
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Offline ValentineWeather

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Re: Freak Wind Storm
« Reply #3 on: May 11, 2017, 09:22:55 PM »
Cool story. I've seen the aftermath of down burst in the forest of North Rim Grand Canyon. Very impressive but if you got caught most likely wouldn't survive.
Randy, the Aviator is my father in 1963 with his Indian bike

Offline alexstaar

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Re: Freak Wind Storm
« Reply #4 on: May 11, 2017, 11:38:58 PM »
Very interesting wind storm. Checked some observation from the local airport there... Looks like the wind may have been caused by a strong wake low. Did the rain stop as the winds increased? The pressure dropped about 4 mb within an hour as the peak winds were recorded at the airport.

https://en.wikipedia.org/wiki/Wake_low
« Last Edit: May 11, 2017, 11:44:33 PM by alexstaar »
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Offline CW2274

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Re: Freak Wind Storm
« Reply #5 on: May 12, 2017, 12:29:06 AM »
https://en.wikipedia.org/wiki/Wake_low
I don't recall ever hearing of such a thing. Thanks for the education.  ;)
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Offline ocala

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Re: Freak Wind Storm
« Reply #6 on: May 12, 2017, 05:42:50 PM »
Very interesting wind storm. Checked some observation from the local airport there... Looks like the wind may have been caused by a strong wake low. Did the rain stop as the winds increased? The pressure dropped about 4 mb within an hour as the peak winds were recorded at the airport.

https://en.wikipedia.org/wiki/Wake_low
When the winds started to pick up we were just north of another round of stratiform rain. It was raining slightly during the event. I know that because I remember thinking that rain hurts your face at 50mph. :grin:
I also checked all the available data I could regarding pressure. Pretty much the area affected had the deepest drop in pressure while 10 miles away the drop wasn't nearly as abrupt.
Definitely a localized event.

Offline ValentineWeather

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Re: Freak Wind Storm
« Reply #7 on: May 12, 2017, 06:58:52 PM »
Here is old photo of one of those freak wind storms in mountains where swath of trees gets blown over.
Randy, the Aviator is my father in 1963 with his Indian bike

Offline ocala

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Re: Freak Wind Storm
« Reply #8 on: May 14, 2017, 06:50:00 AM »
Response from NWS in Burlington, Vt.
They aren't even sure what happened.

Dave,

You're observations are spot on, and to be honest, that is part of what made the event rather unique. In all honesty, we still aren't totally sure about all the specific details that resulted in what happened -- it's something we hope to figure out sometime in the near future.

What we do know ---

During the afternoon we had a band of 50-65 mph winds between 3000-5000ft move northward across Vermont.  This is not uncommon.  The winds were blowing from southeast to northwest, and when they interacted with the steep terrain of the Green Mountains, they created mountain waves  (analogous to ripples in a river as they move over rocks).   The mountain waves act to bring stronger winds closer to the ground.  However, most of the afternoon, even with the mountain waves, the strongest winds still remained well above the ground or restricted to the highest elevations in the mountains. Down at low elevations, such as in Rutland, we typically see a breezy conditions with gusts of 20-30 mph from the east in these situations.  This is what we had in our forecast.   

The short period of rain that moved into the Rutland area in the late afternoon were the remnants of heavier showers and some thunderstorms that occurred earlier in the afternoon across northern NJ.  Our belief is that as the decaying showers interacted with the mountain waves already occurring, the environment changed such that the mountain wave turning into a breaking wave (analogous to ocean waves as they turn into breakers when reaching the beach).  These breaking waves are more violent, and brought these strong winds right down to the ground.  Just like waves on a beach that surge back and forth, these breaking waves will result in surges of wind.  I'm guessing that is what you may have observed as well. Based on the observations we had, the period of damaging winds only lasted about 45 minutes.

Hopefully this makes sense.  Although we expected those stronger winds above the ground to occur, we did not expect the exact conditions to come into play as they did to result in the winds making it to the ground. It ended up being a rather localized event that was likely due to just the right combination of factors that are very difficult to forecast in advance. Thus our desire to do additional research on this particular event so we can do a better job next time.

If you have any questions, please feel free to email me.

Offline PaulMy

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Re: Freak Wind Storm
« Reply #9 on: May 14, 2017, 09:30:54 AM »
Great job of posting your observations here and following up with NWS.  A very good and easy to understand reply from NWS as well.

Enjoy,
Paul

Offline CW2274

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Re: Freak Wind Storm
« Reply #10 on: May 14, 2017, 03:27:43 PM »
the period of damaging winds only lasted about 45 minutes.
Only?  :shock:
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Offline alexstaar

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Re: Freak Wind Storm
« Reply #11 on: May 15, 2017, 12:00:08 AM »
Interesting. I didn't consider the terrain in this locale, but waves seem very possible given that scenario. I wonder if there was perhaps a wake low that interacted with the terrain, creating the waves and enhancing the wake low winds and bringing them down to the surface (3000-5000 feet).
-Alex

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