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June 2012 Severe Weather/Convection Discussion


earthlight

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The GFS seems to like the mid-Atlantic area more, but that can change in a blink. The over all pattern is very ideal with wnw mid-level flow great for EML advection into our area. And it is highly speculative to try and pick out timing and convective mode this far out, but it would appear we may see impulses (presumably MCS's or left over MCV's) travelling west to east out of the Midwest Friday into the weekend.

I really like the pattern as currently progged heading into early July WRT convection risk. Often times we're too far south, with the bulk of the MCS activity running from the G Lakes into NNE. But with this synoptic set-up, mid level ridge centered in the Plains with extension ewd to the Mid-atlantic coast, we'll be near the 582dm height line, and a NW flow aloft. Obviously much too early to get excited, but the next couple weeks certainly have potential to be interesting T-storm wise. Ring of fire type pattern with differential advection in the Lakes and Northeast -- Plains and SE US staying hot and dry.

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I really like the pattern as currently progged heading into early July WRT convection risk. Often times we're too far south, with the bulk of the MCS activity running from the G Lakes into NNE. But with this synoptic set-up, mid level ridge centered in the Plains with extension ewd to the Mid-atlantic coast, we'll be near the 582dm height line, and a NW flow aloft. Obviously much too early to get excited, but the next couple weeks certainly have potential to be interesting T-storm wise. Ring of fire type pattern with differential advection in the Lakes and Northeast -- Plains and SE US staying hot and dry.

Indeed. I'm hoping so, havent seen much at all so far.

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I really like the pattern as currently progged heading into early July WRT convection risk. Often times we're too far south, with the bulk of the MCS activity running from the G Lakes into NNE. But with this synoptic set-up, mid level ridge centered in the Plains with extension ewd to the Mid-atlantic coast, we'll be near the 582dm height line, and a NW flow aloft. Obviously much too early to get excited, but the next couple weeks certainly have potential to be interesting T-storm wise. Ring of fire type pattern with differential advection in the Lakes and Northeast -- Plains and SE US staying hot and dry.

Not sure how anybody gets that excited over the possibility of a lot of severe storms during the prime summer months. I enjoy my outdoor activities, spending time w friends, bbqs, etc. Further, severe storms kill more people than snowstorms and wreak havoc.

Was looking at local obs, and KISP had a pretty crazy yesterday.

46 mph wind gust at 6:00 with 1/4 mile visibility and heavy rain, recorded 1.11 of rain in an hour!

Over 3.5 inches on the day, include 1.75 in an hour in the morning. Very impressive by long island standards, but not fun at all...

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NAM's longer range almost always finds a way to make things interesting... has 100 degree heat on Friday with severe storms crashing into the heat shortly afterwards:

the instability is gonna be insane on friday. just gotta make sure we got enough cape values, shear, mid level lapse rates and also depending on where the storms setup. but friday does look like a good day for severe weather

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The SREF mean is pretty bullish so far (in the extended) for at least some potential Friday Night to maintain a convective system into the Northeast from the Great Lakes. 0-6km and effective bulk shear is in excess of 35 kts with 40+kt values present over Central PA/NY and trying to leak eastward. Instability is obviously very impressive...i'd like to see more impressive forcing but the gradient and height falls could work along the frontal boundary near the area.

The SREF mean probability of 40+ kts effective shear is 50%, which is pretty good in such an unstable airmass.

http://www.spc.noaa.gov/exper/sref/gifs/2012062615/SREF_prob_ESHR_40kt__f081.gif

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The SREF mean is pretty bullish so far (in the extended) for at least some potential Friday Night to maintain a convective system into the Northeast from the Great Lakes. 0-6km and effective bulk shear is in excess of 35 kts with 40+kt values present over Central PA/NY and trying to leak eastward. Instability is obviously very impressive...i'd like to see more impressive forcing but the gradient and height falls could work along the frontal boundary near the area.

The SREF mean probability of 40+ kts effective shear is 50%, which is pretty good in such an unstable airmass.

http://www.spc.noaa...._40kt__f081.gif

im actually cautiously optomistic for this even though im on the coast. lets see if we can get the goods again like yesterday :popcorn:

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The SREF mean is pretty bullish so far (in the extended) for at least some potential Friday Night to maintain a convective system into the Northeast from the Great Lakes. 0-6km and effective bulk shear is in excess of 35 kts with 40+kt values present over Central PA/NY and trying to leak eastward. Instability is obviously very impressive...i'd like to see more impressive forcing but the gradient and height falls could work along the frontal boundary near the area.

The SREF mean probability of 40+ kts effective shear is 50%, which is pretty good in such an unstable airmass.

http://www.spc.noaa.gov/exper/sref/gifs/2012062615/SREF_prob_ESHR_40kt__f081.gif

My main concern is if we have enough forcing/lifting mechanism to overcome what will most likely be very warm mid-level temperatures. Our 700mb temps have a good shot at being at or above the 14C "magic" number which could create capping issues, especially with an EML around.

But with the EML, if the CAP breaks, we're set to go! It's like a loaded gun...just gotta find a way to pull the trigger.

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My main concern is if we have enough forcing/lifting mechanism to overcome what will most likely be very warm mid-level temperatures. Our 700mb temps have a good shot at being at or above the 14C "magic" number which could create capping issues, especially with an EML around.

But with the EML, if the CAP breaks, we're set to go! It's like a loaded gun...just gotta find a way to pull the trigger.

pulling the trigger with the eml and high cape in tandem is gonna be awfully tough to do. but your right if it does game on for the entire tristate and coastal areas for some wicked storms friday evening

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Agree about Friday. 18Z GFS looks pretty good. It weakens the cap (at least in Central NJ) pretty significantly by 21Z which should definitely be breakable and has over 2500 J/kg of SBSCAPE. Mid-levels winds look a little abysmal, with only 20 kts at 500 hPa (with concurrent 0-6 km bulk shear values of about the same) but with such steep lapse rates and an NCAPE of 0.25, seems like anything that goes up could be pretty nasty.

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The models are trying to hone in on a shortwave traveling along the mid level height gradient Thursday Night and Friday morning, shifting south and east from the Great Lakes into the Northeast.

This shortwave would suffice to initiate convection -- the question then becomes whether or not the better wind fields will shift eastward with time to support an organized convective complex. The NAM had been trying to indicate an MCS around 03-09z Friday which would make sense given the aforementioned shortwave timing.

I'm starting to think that the mid level warming could really cap off any convective potential Friday afternoon despite robust instability parameters.

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I'm starting to think that the mid level warming could really cap off any convective potential Friday afternoon despite robust instability parameters.

Agree. The 00Z GFS last night had 20C 800 hPa temperatures above 19.2C temperatures at 850 hPa. The CINH being output is well over 100 J/kg. Deep layer shear is still only 20-30 kts at best, lower than I'd like to see for something organized but probably sufficient for some degree of storm organization at least.

However, I just rein-stalled BUFKIT, and am having trouble figuring something out. The parcel trace is originating at the surface but is colder than the surface. It almost appears as if it is doing a mixed-layer parcel from the lowest 100 hPa or so. Is there a way to change this so that it is surface based? I suspect the CINH output is largely being skewed due to this, and if we could get true surface-based initiation the cap would be much more likely to break. (For example, the 00Z GFS at 21 h has a surface temperature of 32.7C but is providing a parcel with a temperature of about 29C....)

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Agree. The 00Z GFS last night had 20C 800 hPa temperatures above 19.2C temperatures at 850 hPa. The CINH being output is well over 100 J/kg. Deep layer shear is still only 20-30 kts at best, lower than I'd like to see for something organized but probably sufficient for some degree of storm organization at least.

However, I just rein-stalled BUFKIT, and am having trouble figuring something out. The parcel trace is originating at the surface but is colder than the surface. It almost appears as if it is doing a mixed-layer parcel from the lowest 100 hPa or so. Is there a way to change this so that it is surface based? I suspect the CINH output is largely being skewed due to this, and if we could get true surface-based initiation the cap would be much more likely to break. (For example, the 00Z GFS at 21 h has a surface temperature of 32.7C but is providing a parcel with a temperature of about 29C....)

I've had that issue before and couldnt find a fix. It's very odd. My computer has been having issues with bufkit the past few months, too.

I would think, though, that the capping would be strong regardless :lol:

We'll need stronger forcing or height falls which don't look likely...the show may come Friday morning.

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The forecast models (using the NAM as an example) still have the vorticity overhead around 06-09z Friday but at this point it looks like a decaying MCS or one that doesn't feature much organized convection. We'll have to see if this is the case. Either way, the NAM also has 100+ F temps Friday afternoon and strong capping to prevent severe storms.

http://www.meteo.psu.edu/~gadomski/ETANE9_6z/f24.gif

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The 12z NAM has 700mb temps rising above 10C by 6z Fri, in our area. That will tend to kill off convection that approaches late tonight:

2z7kaxw.jpg

You may be right, but Mount Holly specifically notes the significantly elevated instability, all of which is above 700 hPa which could keep the storms going at least aloft.

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