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Could be another heavy rain setup Saturday-Monday, but that is dependent on which model is correct in handling with bermuda high and trough location and speed to the west. 

 

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Welcome!! And great 1st post! I’m guessing you have some kind of 1st responded/military background due to your military clock usage?! Haha   -only use the HRRR inside of 6-8 hours. Beyond th

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1 hour ago, tombo82685 said:

Could be another heavy rain setup Saturday-Monday, but that is dependent on which model is correct in handling with bermuda high and trough location and speed to the west. 

 

 

 

Nice job breaking down the setup differences with the GFS and Euro models. Might actually have learned something. 😉 Keep it up!!

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On 7/13/2021 at 6:53 PM, tombo82685 said:

Could be another heavy rain setup Saturday-Monday, but that is dependent on which model is correct in handling with bermuda high and trough location and speed to the west. 

 

Any updated thoughts on the weekend or still too early to make a guess?

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Hi Guys,

First time poster long time lurker, big fan of blizzards.  I am overseeing a sporting event on Saturday night in Philadelphia from 17:00-22:00 and we know at some point we are going to be hit by rain/thunder.  I know on the twitter account there was a comment on the Union game having issues, but that doesn't start until 19:30.  I'm very amateur compared to the regular phillywx crew; but looking at the shorter-term models, there seems to be a pretty big spread on storm arrival between the RGEM, NAM, and HRRR.  Any thoughts on why and how you typically weight these models?  Is the HRRR even worth looking at more than 24 hours out?

Thanks!

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8 minutes ago, JLS4628 said:

Hi Guys,

First time poster long time lurker, big fan of blizzards.  I am overseeing a sporting event on Saturday night in Philadelphia from 17:00-22:00 and we know at some point we are going to be hit by rain/thunder.  I know on the twitter account there was a comment on the Union game having issues, but that doesn't start until 19:30.  I'm very amateur compared to the regular phillywx crew; but looking at the shorter-term models, there seems to be a pretty big spread on storm arrival between the RGEM, NAM, and HRRR.  Any thoughts on why and how you typically weight these models?  Is the HRRR even worth looking at more than 24 hours out?

Thanks!

Welcome!! And great 1st post! I’m guessing you have some kind of 1st responded/military background due to your military clock usage?! Haha

 

-only use the HRRR inside of 6-8 hours. Beyond that, it’s prone to big swings. 
 

- NAM can get weird too outside of 48 hours. 3k NAM I use for about 36-48 hours out. I barely look at the RGEM . 
 

any higher resolution model tends to be fickle outside that 48 hour timeframe. Especially any CAM’s (Convection Allowing model, EG; 3k NAM, wrf etc). 
 

Gfs tends to be progressive/faster biased, while euro is slower. So most times, if there both doing there bias thing,a blend can work best for timing. 
 

Looking at Saturday: we’ll have a pretty humid, high cape environment. Not the best shear/flow, but we do have an approaching shortwave approaching from the west. Then we have to see about about a lee-side trough triggering storms early, as what usually happens in these uncapped, unstable environments. 
2D40D39A-5CE6-4B82-B884-627B65417A5D.png.fda697cf65c1eff1b72124e72e264bf9.png
 

-2500-3000jnCape

-Total totals around 48.. not bad, not great. 
 

- 25 knots effective shear. Not the best, but some deeper mid level shear could stop storms from collapsing in on themselves. (Organize a bit better)

In simpler terms? Looks like maybe a few different “rounds/opportunists” for storms to fire. Some pre-frontal stuff, which would use up the best thermodynamics, but missing the best lift. This would be scattered hit or miss stuff around in the afternoon- evening. 
 

And then the “main show”. With the approaching front later on in the evening (6-11). 385677AA-1B2C-469D-B38B-A6029B68FD8D.png.d6daf4e6e3b150c63d49e996c3fb8936.png

 

6A47AA0F-7D7E-469E-9CA7-C5D121835A15.png.bb5140e7b1adc0e4846ef3988247631d.png
 

i kind of like the depiction here of how it plays out, so we’ll see. 

Hope this helps !

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6 hours ago, Allsnow said:

He's too busy fantasizing about next weekend's cool shot and low dewpoints. 🌭

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7 hours ago, Allsnow said:

Did it on Twitter. But basically Saturday night rain threat and that’s it after that. Euro was to amplified with shortwave out west which was causing front to hang up on east coast more. 

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Thanks for tips Irishbri; a little concerned about pre-frontal pop-up convection that is appearing on the NAM 3k but at this point, I can't change it, will just have to deal with it.  It would be nice to only have the later t-storms from the frontal passage because that might be after my athletic event is over (in Philadelphia at Franklin Field).  If anyone here has some hankering for pre-Olympic track and field, Ajee Wilson our hometown Olympian will be racing the 800m (https://www.instagram.com/p/CRW0c56jLGW/?utm_source=ig_web_copy_link ).  Admission is free.

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12 hours ago, irishbri74 said:

Welcome!! And great 1st post! I’m guessing you have some kind of 1st responded/military background due to your military clock usage?! Haha

 

-only use the HRRR inside of 6-8 hours. Beyond that, it’s prone to big swings. 
 

- NAM can get weird too outside of 48 hours. 3k NAM I use for about 36-48 hours out. I barely look at the RGEM . 
 

any higher resolution model tends to be fickle outside that 48 hour timeframe. Especially any CAM’s (Convection Allowing model, EG; 3k NAM, wrf etc). 
 

Gfs tends to be progressive/faster biased, while euro is slower. So most times, if there both doing there bias thing,a blend can work best for timing. 
 

Looking at Saturday: we’ll have a pretty humid, high cape environment. Not the best shear/flow, but we do have an approaching shortwave approaching from the west. Then we have to see about about a lee-side trough triggering storms early, as what usually happens in these uncapped, unstable environments. 
2D40D39A-5CE6-4B82-B884-627B65417A5D.png.fda697cf65c1eff1b72124e72e264bf9.png
 

-2500-3000jnCape

-Total totals around 48.. not bad, not great. 
 

- 25 knots effective shear. Not the best, but some deeper mid level shear could stop storms from collapsing in on themselves. (Organize a bit better)

In simpler terms? Looks like maybe a few different “rounds/opportunists” for storms to fire. Some pre-frontal stuff, which would use up the best thermodynamics, but missing the best lift. This would be scattered hit or miss stuff around in the afternoon- evening. 
 

And then the “main show”. With the approaching front later on in the evening (6-11). 385677AA-1B2C-469D-B38B-A6029B68FD8D.png.d6daf4e6e3b150c63d49e996c3fb8936.png

 

6A47AA0F-7D7E-469E-9CA7-C5D121835A15.png.bb5140e7b1adc0e4846ef3988247631d.png
 

i kind of like the depiction here of how it plays out, so we’ll see. 

Hope this helps !

nice write up Bri

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2 things I'm worried about for today. 

1. Being displaced further south from main dynamics with area of low pressure to our northeast. So main convection goes nw while we get a broken line of something.

2. Any prefrontal convection, in terms of reducing instability due to rains or anvil tops getting sheared out towards leaving us in cloudier regime right before main line comes in.

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3 hours ago, tombo82685 said:

2 things I'm worried about for today. 

1. Being displaced further south from main dynamics with area of low pressure to our northeast. So main convection goes nw while we get a broken line of something.

2. Any prefrontal convection, in terms of reducing instability due to rains or anvil tops getting sheared out towards leaving us in cloudier regime right before main line comes in.

Yeah definitely looks like the main show will be to our north

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30 minutes ago, Colin said:

Yeah definitely looks like the main show will be to our north

For heavy rain yes, svr probably not 

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On 7/16/2021 at 7:39 AM, irishbri74 said:

Welcome!! And great 1st post! I’m guessing you have some kind of 1st responded/military background due to your military clock usage?! Haha

 

-only use the HRRR inside of 6-8 hours. Beyond that, it’s prone to big swings. 
 

- NAM can get weird too outside of 48 hours. 3k NAM I use for about 36-48 hours out. I barely look at the RGEM . 
 

any higher resolution model tends to be fickle outside that 48 hour timeframe. Especially any CAM’s (Convection Allowing model, EG; 3k NAM, wrf etc). 
 

Gfs tends to be progressive/faster biased, while euro is slower. So most times, if there both doing there bias thing,a blend can work best for timing. 
 

Looking at Saturday: we’ll have a pretty humid, high cape environment. Not the best shear/flow, but we do have an approaching shortwave approaching from the west. Then we have to see about about a lee-side trough triggering storms early, as what usually happens in these uncapped, unstable environments. 
2D40D39A-5CE6-4B82-B884-627B65417A5D.png.fda697cf65c1eff1b72124e72e264bf9.png
 

-2500-3000jnCape

-Total totals around 48.. not bad, not great. 
 

- 25 knots effective shear. Not the best, but some deeper mid level shear could stop storms from collapsing in on themselves. (Organize a bit better)

In simpler terms? Looks like maybe a few different “rounds/opportunists” for storms to fire. Some pre-frontal stuff, which would use up the best thermodynamics, but missing the best lift. This would be scattered hit or miss stuff around in the afternoon- evening. 
 

And then the “main show”. With the approaching front later on in the evening (6-11). 385677AA-1B2C-469D-B38B-A6029B68FD8D.png.d6daf4e6e3b150c63d49e996c3fb8936.png

 

6A47AA0F-7D7E-469E-9CA7-C5D121835A15.png.bb5140e7b1adc0e4846ef3988247631d.png
 

i kind of like the depiction here of how it plays out, so we’ll see. 

Hope this helps !

You're in cold season form already! 

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Question for the professionals and those willing to take a shot at this question.

Given the smoke/haziness in the air, how much does that factor in to the SPC putting out a slight risk for severe storms?   Wouldn't a lot of that energy be "stolen" by the smoke/haze since it seems like temps are capped under that cover?

 

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I would imagine it cuts down on CAPE quite a bit, but SPC Mesoscale analysis is still predicting us to get to about 3k Surface CAPE and 1500-2k K/Kg MLCAPE which should be plenty to fire up the storms. This (anecdotally based on when I check in) is about 60-75% of our peak CAPE this time of year. It's not unusual to see us at 4.5k surface and over 3k ML on a hot high 80s day like today if it is clear.

I also wonder in cases like today how far out front the cold front pushes the smoke out of the way. Are we possibly looking at 1-2 hour window of significant clearing and heating ahead of the front? Visible sat this morning appears to have the smoke just sitting ahead of the front.

disclaimer: I'm by no means a professional :)

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