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George BM

July Discobs 2019

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10 minutes ago, C.A.P.E. said:

Once we get into winter the LR guidance will perpetually advertise a big NA block that will never materialize in real time.

Should be illegal to even commnet on the weeklies once we get to close winter.  Sorry, did I say weeklies, I mean the weaklings ...   

 

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I live in New Jersey and we get thunderstorms all summer long. We are used to it. But Monday we had a line of them move through and they were very, very strong. There was a lot of damage. I had no electricity for 26 hours, some people still have no power.

My question is why were these storms so intense? Was this a derecho? I have asked this question on other forums and haven't gotten a decent answer. Perhaps an actual meteorologist can answer this for me. Thanks. 

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On 7/25/2019 at 11:08 AM, terpodion said:

I live in New Jersey and we get thunderstorms all summer long. We are used to it. But Monday we had a line of them move through and they were very, very strong. There was a lot of damage. I had no electricity for 26 hours, some people still have no power.

My question is why were these storms so intense? Was this a derecho? I have asked this question on other forums and haven't gotten a decent answer. Perhaps an actual meteorologist can answer this for me. Thanks. 

Well I'm certainly no meteorologist but I do know somethings about meteorology so here it goes.

This past Monday, as you probably know, was the last day of the heatwave in the region. Very hot surface temperatures usually correspond with very steep low-level lapse rates which can help with higher winds aloft being mixed down to the ground say with, for example, a line of thunderstorms ;). Now this past Monday NJ had an area of 3,000+J/kg of mlcape (Mixed-layer convective available potential energy), which is fairly high (higher than usual), due to the high heat and humidity (surface temps in the 90's and dewpoints in the 70's). With you being in central NJ that means your area missed the previous days storms. This is important because it means that nothing was able to stabilize and moisten the atmosphere. That means that there was some drier air aloft (10,000-20,000ft) for Monday afternoon in your area. So, when strong heating of a moist boundary-layer (the layer below the cumulus clouds) helped cumulus clouds grow into cumulonimbus clouds the water droplets evaporated in the dry air which causes it to cool and sink creating a downdraft. On Monday afternoon there were also some stronger winds aloft around the 700-600mb layer (10,000-15,000ft above the ground) of around 35-40 kts. That can help storm clusters generate a cold-pool and with warm/moist air being forced upwards ahead of the storms and the rain cooled air (the cold-pool) sinking as they move through this creates a feedback loop allowing the storms to accelerate forward to 35-40kts (40-46mph) or faster especially if instability is strong (which it was on Monday). The storms on Monday blasted through your area at 50-60 mph and with the steep low-level lapse rates in place a lot of that wind energy was able to reach the ground. The result is widespread 50-60 mph wind gusts. However, with stronger downdrafts embedded within the line of storms they could've added 15-20+mph to the 50-60 mph winds in localized areas.

This is my two cents on Monday's storms in your area. I'm no meteorologist or expert for that matter and I probably look like a total fool to those experts. Oh well, I live and I learn and boy do I have a lot to learn in this field. I also apologize for the horrible grammar. I hope you were able to understand something through all that. Hopefully an actual expert can clarify what the heck I just tried to say lol.

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On 7/24/2019 at 12:11 PM, yoda said:

Figured this would get more traffic and be seen more in this thread... but LWX is holding an online webinar basic skywarn class to be a spotter on August 13th from 6pm to 8pm for ALL LWX Sterling counties

https://www.weather.gov/lwx/skywarn

 

skywarnonlineclass.thumb.png.855534ee8dfda43fe60863e7769c6e05.png

 

Hurry and get your spot if you have ever wanted to be a spotter for LWX and never got the time to go to one of the classes... or if you wish to refresh your knowledge (LWX says you should take a refresher course every 3-4 years if you already are a spotter for them).  I just registered since I last took the class in 2016... there were something like 35 spots left, so get your spot now!  It's also nice that LWX was able to do this so that you don't have to travel anywhere... you can take the class from your own computer at home and then become a spotter :) 

 

From the eventbrite link provided in the image:

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19 hours ago, George BM said:

Well I'm certainly no meteorologist but I do know somethings about meteorology so here it goes.

This past Monday, as you probably know, was the last day of the heatwave in the region. Very hot surface temperatures usually correspond with very steep low-level lapse rates which can help with higher winds aloft being mixed down to the ground say with, for example, a line of thunderstorms ;). Now this past Monday NJ had an area of 3,000+J/kg of mlcape (Mixed-layer convective available potential energy), which is fairly high (higher than usual), due to the high heat and humidity (surface temps in the 90's and dewpoints in the 70's). With you being in central NJ that means your area missed the previous days storms. This is important because it means that nothing was able to stabilize and moisten the atmosphere. That means that there was some drier air aloft (10,000-20,000ft) for Monday afternoon in your area. So, when strong heating of a moist boundary-layer (the layer below the cumulus clouds) helped cumulus clouds grow into cumulonimbus clouds the water droplets evaporated in the dry air which causes it to cool and sink creating a downdraft. On Monday afternoon there was also some stronger winds aloft around the 700-600mb layer (10,000-15,000ft above the ground) of around 35-40 kts. That can help storm clusters generate a cold-pool and with warm air being forced upwards ahead of the storms and the rain cooled air (the cold-pool) sinking as they move through this creates a feedback loop allowing the storms to accelerate forward to 35-40kts (40-46mph) or faster especially if instability is strong (which it was on Monday). The storms on Monday blasted through your area at 50-60 mph and with the steep low-level lapse rates in place a lot of that wind energy was able to reach the ground. The result is widespread 50-60 mph wind gusts. However, with stronger downdrafts embedded within the line of storms they could've added 15-20+mph to the 50-60 mph winds in localized areas.

This is my two cents on Monday's storms in your area. I'm no meteorologist or expert for that matter and I probably look like a total fool to those experts. Oh well, I live and I learn and boy do I have a lot to learn in this field. I also apologize for the horrible grammar. I hope you were able to understand something through all that. Hopefully an actual expert can clarify what the heck I just tried to say lol.

great write up! 

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On 7/25/2019 at 10:49 AM, C.A.P.E. said:

Once we get into winter the LR guidance will perpetually advertise a big NA block that will never materialize in real time.

Today's guidance even deeper with the -NAO coming  up. On on the flip side, this has caused a significant increase in the SST up North. 

(chart courtesy of bluewave ) 

 

7071AFC6-F2BE-470E-B851-8F54DDA4F775.png.a2ab4b5378fd2ea57b4740901ba45bf4.png

 

 

 

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To follow up on the  -NAO I took this image from the NY City forum, again courtesy of bluewave, where I asked him a question about the changing cold pool and how it has warmed. This really shows the dramatic change in the Atlantic SSTs over the past couple months.

Also,  look to the Pac and the Gulf of Alaska, as you know Alaska has been seeing incredible warmth. maybe lead to a +PDO. 

This is only a anomaly map, but still very interesting. 

I recall reading or hearing, a very warm Atlantic in October and November can act like a magnet drawing cold to its source region off of the North Amercian continet later in October and early November. Don't hold me to that as I believe I read it years ago. And, these so called changes can occur on the flip of switch. Similiar to last year.   

582319C3-9E5C-4A69-9A1B-56A2D943A10F.thumb.gif.71da90b2c0671bb536bfd665c5e03984.gif

 

 

  

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Both the Pacific and Atlantic are opposite of last year, kind of a flat lining I think. The PNA was really persistently negative 2017-2018, and really changed last Nov-Dec to more neutral, or late 70's-like. It's a different pattern, I expect us to find other planets lol. 

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Goes to show you how hard the NAO is to predict, no one really knows, including the models and even the impressive EPS. 

 

  

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44 minutes ago, frd said:

Goes to show you how hard the NAO is to predict, no one really knows, including the models and even the impressive EPS. 

 

  

At least the models are consistently bad through the seasons with predicting it. I must say though, it is so awesome to have this persistent -NAO for the summer!

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40 minutes ago, JakkelWx said:

Avg temp is almost a degree cooler from a week ago.

Does it seriously peak in mid or late July? That's incredible. Or are you saying this week is cooler than last week?

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26 minutes ago, Vice-Regent said:

Does it seriously peak in mid or late July? That's incredible. Or are you saying this week is cooler than last week?

It does. Extrapolating the average temp chart for my area peaks in mid-late July 

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55 minutes ago, mattie g said:

Why would that be incredible? It makes sense.

Over here it's different because sea surface temperatures peak in August and the SST will determine the daily maximum.

I think most of us would agree that using average temperature guidance in short-term forecasting will not help much or even hurt you these days. We haven't cooled down because of any seasonal progression. By and large high-end heat has been rare this summer due to the -NAO/-AO couplet and we had a regression to the mean.

A reliable indicator of our seasonal pattern are the European temperature anomalies.

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