May 15 2018 Severe Threat SNE

[Typhoon Tip]

we're also getting some muted warm up with this stubborn strata along the Pike in the interior.  Sat trends do suggest it is eroding ... It probably won't matter if/when the diffused warm boundary works through - 

[HoarfrostHubb]

  On 5/15/2018 at 1:50 PM, weatherwiz said:

Sick!!! Didn't even see that tweet. Just got in from cutting grass. I want me a derecho

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SW CT into Long Island?

[Hoth]

Sam L is apparently not happy with SPC's choice of the "d" word.

[ma blizzard]

  On 5/15/2018 at 1:56 PM, Hoth said:

Sam L is apparently not happy with SPC's choice of the "d" word.

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agreed .. you can't just throw that word out there - should be determined in post-analysis imo.

[weatherwiz]

  On 5/15/2018 at 1:56 PM, HoarfrostHubb said:

SW CT into Long Island?

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probably should see a nasty line that moves into western/central MA and down through western/central CT into SE NY and into NJ. I will be in the Danbury area too!

[Damage In Tolland]

  On 5/15/2018 at 1:56 PM, HoarfrostHubb said:

SW CT into Long Island?

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Approximately I-90 south it appears to about the RI border. Based on all short range/ hi res stuff 

[HoarfrostHubb]

 The UVV field related to the MCV appears
   well-timed to encounter the destabilizing warm sector across
   northern PA today, along and south of the frontal zone, in support
   of initial development, which then should expand/intensify to severe
   levels as it moves rapidly eastward toward parts of southern NY, NJ
   and New England.  Whether the resulting convective wind event
   qualifies as a derecho may be a semantic exercise; impacts could be
   of that caliber in the area affected.

[WxBlue]

  On 5/15/2018 at 1:56 PM, Hoth said:

Sam L is apparently not happy with SPC's choice of the "d" word.

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I don't blame him. There's a LARGE difference between run-of-the-mill straight line event and a classic derecho. Yet, it seems like we're calling almost every straight line event a potential derecho these days. Thanks, 2012.

 

[Hoth]

  On 5/15/2018 at 2:02 PM, ma blizzard said:

agreed .. you can't just throw that word out there - should be determined in post-analysis imo.

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Aren't there certain specific atmospheric criteria that have to be met too? 

[HoarfrostHubb]

Based on the text I quoted, I don't think they are actually calling for a derecho...but derecho-like impacts...whatever that means

[WxBlue]

  On 5/15/2018 at 2:06 PM, Hoth said:

Aren't there certain specific atmospheric criteria that have to be met too? 

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http://www.spc.noaa.gov/misc/AbtDerechos/derechofaq.htm

By definition, a derecho must include wind gusts of at least 58 mph (50 knots or 93 km/h) or greater along most of its length. 

A derecho wind damage swath must extend more than 240 miles (about 400 kilometers). This criterion is used to eliminate more common, shorter-lived, and generally less-organized wind-producing convective systems. Although no formally-recognized width criterion exists for a derecho, the nature of the storm systems responsible for their development dictates that most derechos span at least 50 miles (80 km) in width. 

[powderfreak]

  On 5/15/2018 at 2:09 PM, HoarfrostHubb said:

Based on the text I quoted, I don't think they are actually calling for a derecho...but derecho-like impacts...whatever that means

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No tree left standing from ALB to ORH.

[HoarfrostHubb]

  On 5/15/2018 at 2:10 PM, powderfreak said:

No tree left standing from ALB to ORH.

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Denuded

3k NAM has the line holding together even into Scotter and Bob-land

[Typhoon Tip]

  On 5/15/2018 at 2:06 PM, Hoth said:

Aren't there certain specific atmospheric criteria that have to be met too? 

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It's like everything in nature ... distinctions go along human designs/conventions but the boundaries between event "types" are, in reality, blurry ...  It's a spectrum of events, black at one end...white at the other, smooth and seamlessly tinting from dark to the light end, and every event is just a point on that spectrum. 

That's really how Nature distinguishes events...  

Case in point, the difference between a hurricane, a hybrid/subtropical cyclone, or an extra-tropical cold core cyclone...  There are systems that exist in between those distinctions, yet the propensity of science to label them ...you know? 

If you have a thunderstorm micro burst, or a cluster of cyclic cells moving along and aggregating their outflow into a "macro" burst, ..or an outward propagating pool of rain cooled air lifting an environmental inflow into a self sustaining MCS ... they are all cousins - so to speak - within a physical envelope along a similar spectrum. 

It's just that the single thunderstorm is at one end of the spectrum and the Derecho is at the other for that particular comparison... 

[powderfreak]

Is the storm threat that thing moving into ALB area now or is it going to be south of there later, associated with like the outflow boundary of that current line of storms?

I'm heading to my folks house just SW of ALB and it's pitch black off to the west with good lightning visible from I-87.

[WxBlue]

Clouds cleared out of western Mass and CT. They should be good to go later this afternoon.

[dmillz25]

  On 5/15/2018 at 2:16 PM, powderfreak said:

Is the storm threat that thing moving into ALB area or is it going to be south of there later, associated with like the outflow boundary of that current line of storms?

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The second part 

[Hoth]

  On 5/15/2018 at 2:13 PM, Typhoon Tip said:

It's like everything in nature ... distinctions go along human designs/conventions but the boundaries between event "types" are, in reality, blurry ...  It's a spectrum of events, black at one end...white at the other, smooth and seamlessly tinting from dark to the light end, and every event is just a point on that spectrum. 

That's really how Nature distinguishes events...  

Case in point, the difference between a hurricane, a hybrid/subtropical cyclone, or an extra-tropical cold core cyclone...  There are systems that exist in between those distinctions, yet the propensity of science to label them ...you know? 

If you have a thunderstorm micro burst, or a cluster of cyclic cells moving along and aggregating their outflow into a "macro" burst, ..or an outward propagating pool of rain cooled air lifting an environmental inflow into a self sustaining MCS ... they are all cousins - so to speak - within a physical envelope along a similar spectrum. 

It's just that the single thunderstorm is at one end of the spectrum and the Derecho is at the other for that particular comparison... 

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Well said. It's a beautiful spectrum.

[HoarfrostHubb]

  On 5/15/2018 at 2:16 PM, powderfreak said:

Is the storm threat that thing moving into ALB area or is it going to be south of there later, associated with like the outflow boundary of that current line of storms?

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The bigger threat is the southeast part to come later today...4-9PM or so

[Damage In Tolland]

  On 5/15/2018 at 2:10 PM, powderfreak said:

No tree left standing from ALB to ORH.

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All Oaks down 

[WxBlue]

  On 5/15/2018 at 2:16 PM, powderfreak said:

Is the storm threat that thing moving into ALB area now or is it going to be south of there later, associated with like the outflow boundary of that current line of storms?

I'm heading to my folks house just SW of ALB and it's pitch black off to the west with good lightning visible from I-87.

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The latter. What you're seeing is the first round that'll move through S VT, S NH, and north of I-90 in Mass. It'll lay down that OFB south of these storms for later event like you mentioned.

[HoarfrostHubb]

  On 5/15/2018 at 2:19 PM, Damage In Tolland said:

All Oaks down 

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Trees damaged from gypsy moth caterpillars could be an issue

[HoarfrostHubb]

Should Wiz break out a seperate thread for this threat?

[powderfreak]

Thanks guys, that's what I was leaning towards.  Too early with this first line and see secondary stuff going out west in WNY/WPA.

[weatherwiz]

I'm hanging out with this girl today and I told her about the elevated mixed-layer and how we're going to get nasty storms and she is down to go and watch them come in!!! 

[Hoth]

  On 5/15/2018 at 2:26 PM, weatherwiz said:

I'm hanging out with this girl today and I told her about the elevated mixed-layer and how we're going to get nasty storms and she is down to go and watch them come in!!! 

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What else is she down for?

[Typhoon Tip]

  On 5/15/2018 at 2:26 PM, weatherwiz said:

I'm hanging out with this girl today and I told her about the elevated mixed-layer and how we're going to get nasty storms and she is down to go and watch them come in!!! 

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Nice! ... don't forget to show 'er ur tornado while ur at it ... 

[HoarfrostHubb]

  On 5/15/2018 at 2:28 PM, Typhoon Tip said:

Nice! ... don't forget to show 'er ur tornado while ur at it ... 

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He will whip out his baseball scoring book and explain the nuances of a suicide squeeze while an EF3 rages 5 miles away

[Ginx snewx]

  On 5/15/2018 at 2:12 PM, HoarfrostHubb said:

Denuded

3k NAM has the line holding together even into Scotter and Bob-land

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If you look at it closely that line falls apart as it approaches the marine layer though. It does have a Meso/supercell? that starts in the Berks and travels to ORH county

[Typhoon Tip]

  On 5/15/2018 at 2:20 PM, WxBlue said:

The latter. What you're seeing is the first round that'll move through S VT, S NH, and north of I-90 in Mass. It'll lay down that OFB south of these storms for later event like you mentioned.

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Yup! 

I discussed this very same aspect on the last page... It may mute areas that rain cool but watch that outflow termination axis ... it'll lay down WSW - ENE some 20 or 30 or so miles (not withstanding topographic blocking...) S of the transit and could be a good trigger -