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Northeast Severe/Convective/Thunder thread IV


NJwinter23

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I completely agree with this statement. Just looked at the latest guidance from the NAM, GFS, and Euro. They all have the vort max centered around the midway(somewhere between Worcester and Springfield) point of SNE by 18Z tomorrow. So I would expect most of us to be able to see something tomorrow morning. And then for the afternoon, extreme Eastern areas of SNE could possibly see some action. All three pieces of guidance do develop a region of QPF centered along the south coast. Basically SE Mass, RI and the Cape.

Edit: By "most of us see something" I meant billowing clouds and a thunderstorm off in the distance as someone else gets it. lol

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I wonder if we could get a decent MCS out of this farther west. The Euro has pretty explosive thunderstorm development this evening/overnight. Not a terrible pattern for a derecho but the lack of good LLJ winds/convergence is probably an issue.

The ECMWF was also a bit warm on the initialization from what I read from PHL. Considering the poor conditions for a derecho, I would imagine any issue with buoyancy would be quite considerable to MCS genesis. Having said that, I do feel this set up can produce a nice MCS.

I know this is extrapolating, but I could see the heat building east again for a time in the second half of the month as the ridge flattens again. You almost can see those signs on the euro ensembles.

Yes, it is quite possible to have two upper anticyclones positioning over the western High Plains / Rockies and western Atlantic.

I don't think you mis-understood, I wasn't too specific with the exact days and this is all confusing speculation anyways. And between the data overload we deal with in this field, I'm not sure I know what day it is most of the time lol.

I remember that feeling well. :axe:

Yeah Monday i was safely into the office by then, and had a great view of the pitch blackness ensuing.

Despite not having access to the best data, you still appear to have a great handle on where the pattern may be going. Excellent general climo knowledge as always too!

Thanks man.

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Yes, it is quite possible to have two upper anticyclones positioning over the western High Plains / Rockies and western Atlantic.

It's all about conservation of mass. Mass is never lost/destroyed in the atmosphere. If you have a ridge, you have to have "enough" mass in trough to compensate. They will always = 0.

If there is upper cyclones positioned infinitum, the only requirement is that there is troughing somewhere sufficient to compensate.

The problem becomes when you have nested wave signatures that cross over the domain boundaries in the atmosphere. That may give the illusion of unbalanced mass fields, but really, the domain space just needs to be increased in order to find the necessary compensating mass field. For example, a hugely -WPO may not mean much to us here in the U.S. because it is so far away, and with all the other teleconnectors that are more effective on our pattern due to their closeness and so forth, but that doesn't not mean that a mass sink or gain there isn't being transitively assisted by our local mass fields - transitive in the sense that the 3 or 5th (etc) component is affected by the character of the first, not necessarily the 2nd.

That gets the whole teleconnector juggling game real interesting, if not migrainous at times.

Another way to look at this is "sloshing" in a swimming pool. You can have long period oscillations that are undulating under the chop of the surface where kids are flapping around. Same holds true in the atmosphere. If it "appears" odd to have anticyclones positioned as described, it could be an error, but it could be a slosh super-imposed over L/W frequencies just the same.

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For Friday...........AWT

...NEW ENGLAND...

A SHORTWAVE RIDGE WILL EXIST OVER THE REGION EARLY...WITH SWLY LOW

LEVEL FLOW AND WARM ADVECTION. A FEW EARLY STORMS MAY EXIST ACROSS

SRN NEW ENGLAND WITH HEAVY RAIN AS WELL AS MARGINAL HAIL...BUT THE

BEST CHANCE OF SEVERE STORMS WILL BE OVER ME IN CLOSER PROXIMITY TO

THE BETTER HEIGHT FALLS AND UPPER VORTICITY AXIS LATER IN THE DAY.

INCREASING WIND SPEEDS WITH HEIGHT AND MODESTLY STEEP LAPSE RATES

ALOFT SHOULD SUPPORT VIGOROUS UPDRAFTS CAPABLE OF HAIL. HODOGRAPHS

MAY BE FAVORABLE FOR SPLITTING CELLS.

FARTHER S INTO SERN NEW ENGLAND...THE FRONTAL PASSAGE APPEARS TO BE

OCCURRING TOO EARLY FOR ANY SIGNIFICANT SEVERE THREAT WITH SOME

DRYING ALOFT AFTER 18Z. IF THE SYSTEM PROGRESSES JUST A BIT

SLOWER...THE BOSTON AREA COULD SEE A THREAT OF ISOLATED SEVERE.

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If anything, maybe SE MA has the best shot.

Models seem to be keying on a second vort max by 00z that's diving into central NE. GFS dries out tne boundary layer too fast for much fun western and central areas. I'm not sure we'll be able to break the cap even if the NAM is right.

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Models seem to be keying on a second vort max by 00z that's diving into central NE. GFS dries out tne boundary layer too fast for much fun western and central areas. I'm not sure we'll be able to break the cap even if the NAM is right.

I see what you mean. Maybe that's enough to ignite some isolated stuff?

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I see what you mean. Maybe that's enough to ignite some isolated stuff?

Could be as long as dews don't plummet. Interesting to see MET MOS drop dews quickly like the GFS while the actual 2m dews on the model stay high at BDL through the afternoon.

Weird.

SREFs also keep things juicy.

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Either way, I'd want to be in ME tomorrow. Maybe if things clear out quick enough, we can get a few storms into eastern areas.

SREF has had at least subtle hints of sig. severe for at least 24 hours worth of runs now up this way.

Just straight extrapolation of the current shortwave motion puts it into the CT River Valley by 10 AM tomorrow. But it will lift ENE with time, with the southern end of the forcing lagging that timing by a few hours. We should have the front pretty close to overhead at GYX by early afternoon tomorrow.

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SREF has had at least subtle hints of sig. severe for at least 24 hours worth of runs now up this way.

Just straight extrapolation of the current shortwave motion puts it into the CT River Valley by 10 AM tomorrow. But it will lift ENE with time, with the southern end of the forcing lagging that timing by a few hours. We should have the front pretty close to overhead at GYX by early afternoon tomorrow.

Instability is going to be quite impressive. Shear is solid as well. Up your way the cap shouldn't be much of an issue... down here I'm not sure we can erode it. I like ME for a decent sized event tomorrow.

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Instability is going to be quite impressive. Shear is solid as well. Up your way the cap shouldn't be much of an issue... down here I'm not sure we can erode it. I like ME for a decent sized event tomorrow.

Forecast winds have veered a bit since yesterday, but if we can keep them in the 225orange it could be very interesting for Fryeburg through Skowhegan.

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best bet down here in SNE might be a couple of isolated cells in the afternoon hours...but anything that finally manages to pop goes to town?

There's a fair amount of convergence tomorrow along the slow moving front plus a bit of synoptic help with the s/w. I agree isolated but anything that can break the cap could be big.

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Instability is going to be quite impressive. Shear is solid as well. Up your way the cap shouldn't be much of an issue... down here I'm not sure we can erode it. I like ME for a decent sized event tomorrow.

I honestly have little confidence on anything here. I'm thinking little action here, but there is part of me thinking we could somehow sneak some sort of a line in. Some hints that areas could get a decent storm in the morning perhaps.

I did notice the NAM has a decent KI spike in the afternoon. Could be a signal I suppose.

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I honestly have little confidence on anything here. I'm thinking little action here, but there is part of me thinking we could somehow sneak some sort of a line in. Some hints that areas could get a decent storm in the morning perhaps.

I did notice the NAM has a decent KI spike in the afternoon. Could be a signal I suppose.

Yeah the issue I think is getting something to break the cap. At least eastern areas will have good instability... back here we have to worry about drying out too quickly AND breaking the cap. More wiggle room out your way.

Worth watching because anything that goes up could produce siggy svr.

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There's a fair amount of convergence tomorrow along the slow moving front plus a bit of synoptic help with the s/w. I agree isolated but anything that can break the cap could be big.

i don't like when guidance throws up virtually nothing for QPF.

the late afternoon soundings from the NAM at BDL are impressive.

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