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SNE severe/convective thread IX...or whatever number we're on


weatherwiz

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Interesting HM and I really would not know. You're going to have to help me here as the summer-time is not my forte with long-range/pattern recognition. For a while there (within the past couple weeks), we were in a pattern (or at least one was being predicted by the models that may have not fully materialized) where I thought it looked El Nino-like..it featured the warmest anomalies/ridges rolling northward into Canada, and the return easterly flow underneath was leading to cooler/wetter anomalies across the south and into Texas...am I right to connect that to an el-nino tendency in the summer-time? with that said, such a pattern did not look favorable at all for increased wind shear/wind max's rolling through eastern North America.

Edit: It was in the time frame following the EML/derecho setup.

I think for the most part, El Nino has not had much of an effect yet on our pattern and the residual La Nina-tendency has dominated. The entire EURO-Asian-N PAC sector is behaving more like a -PDO / La Nina and therefore the pattern over N. America is too. El Nino tends to produce higher heights over Alaska and a downstream trough over the western portion of the USA in July, possibly setting the stage climatically for a possible EML advection. It is the only month in the warm season where an El Nino-tendency is probably more attributable to a possible EML advection per jet / advection processes.

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shear/cape juxtaposition is actually a bit better than I thought. 40 kt of deep layer shear and 2000 MLCAPE showing up in western MA already. There is still a weak EML present over SNE. It is more apparent in the OKX sounding than CHH.

I agree that right now things are pretty awesome over New England / E NY and the only thing hurting is the time of day.

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I think for the most part, El Nino has not had much of an effect yet on our pattern and the residual La Nina-tendency has dominated. The entire EURO-Asian-N PAC sector is behaving more like a -PDO / La Nina and therefore the pattern over N. America is too. El Nino tends to produce higher heights over Alaska and a downstream trough over the western portion of the USA in July, possibly setting the stage climatically for a possible EML advection. It is the only month in the warm season where an El Nino-tendency is probably more attributable to a possible EML advection per jet / advection processes.

Yeah the gist of what I was getting at is, why would more of an El-nino tendency lead to a potentially better wind/eml setup in the current timeframe (which you did a great job of answering)..

Without question the residual la nina tendency has dominated the majority of the north american pattern, with the strong -pdo cool pool leading the way. Closer to the Tropics have looked more el nino-like though (makes sense with the 1-2 warm pool), perhaps shown in the wetter south/Texas (which we did not see of course in the past 2 la nina summers) and the over all tropical atlantic behavior early on this season

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similar CAPE/shear parameters to what we saw yesterday over WNY. However, it looks like the lift is better in SNE today and you won't have to break a 13C 700mb cap from an EML. SPC SREF post-processed guidance is putting a nice 40% severe area right near the MA/CT/RI border.

rev kev's house should get all lit up

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Yeah the gist of what I was getting at is, why would more of an El-nino tendency lead to a potentially better wind/eml setup in the current timeframe (which you did a great job of answering)..

Without question the residual la nina tendency has dominated the majority of the north american pattern, with the strong -pdo cool pool leading the way. Closer to the Tropics have looked more el nino-like though (makes sense with the 1-2 warm pool), perhaps shown in the wetter south/Texas (which we did not see of course in the past 2 la nina summers) and the over all tropical atlantic behavior early on this season

The feedback process is no doubt beginning to have an effect over portions of the Subtropics; but, the majority of the NH is still in La Nina mode.

Part of the reason I made this forecast: http://www.americanwx.com/bb/index.php/topic/35289-northeast-severeconvectivethunder-thread-v/page__st__840__p__1634004#entry1634004 was because I anticipated a brief +daam/dt period and the models were hinting at that possibility.

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The feedback process is no doubt beginning to have an effect over portions of the Subtropics; but, the majority of the NH is still in La Nina mode.

Part of the reason I made this forecast: http://www.americanw...04#entry1634004 was because I anticipated a brief +daam/dt period and the models were hinting at that possibility.

FNL GWO Numbers:

348 2012 6 29 -1.78 -0.30 10 2.5 1.8

349 2012 6 30 -1.88 -0.59 10 2.5 2.0

350 2012 7 1 -1.89 0.17 10 2.5 1.9

351 2012 7 2 -1.85 0.50 10 2.5 1.9

352 2012 7 3 -1.78 0.46 10 2.5 1.8

353 2012 7 4 -1.74 -0.08 10 2.5 1.7

354 2012 7 5 -1.78 0.14 10 2.5 1.8

355 2012 7 6 -1.68 1.31 15 3.5 2.1

356 2012 7 7 -1.44 2.44 15 3.5 2.8

357 2012 7 8 -1.09 2.42 15 3.5 2.7

358 2012 7 9 -0.86 1.28 15 3.5 1.5

359 2012 7 10 -0.75 0.83 15 3.5 1.1

360 2012 7 11 -0.68 -0.71 5 1.5 1.0

361 2012 7 12 -0.90 -1.63 5 1.5 1.9

362 2012 7 13 -1.01 0.06 10 2.5 1.0

363 2012 7 14 -0.91 1.07 15 3.5 1.4

364 2012 7 15 -0.78 0.63 15 3.5 1.0

365 2012 7 16 -0.74 0.28 10 2.5 0.8

366 2012 7 17 -0.63 1.93 20 4.5 2.0

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If it completely misses it would be understandable given that the front is almost right on top of us already… If it slips south in the next 2 hours, we watch the back sides of CBs painfully slip away. I used see this all the time in the late 1980s – we were in summers that kept having noon frontal passages, CBs would fire S and you watch with envious jealous eyes as though the whole thing was a tortured set up. I just get bitter when I recognize this sort of scenario being set up…

We’ll see:

90fwbg.gif

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The feedback process is no doubt beginning to have an effect over portions of the Subtropics; but, the majority of the NH is still in La Nina mode.

Part of the reason I made this forecast: http://www.americanw...04#entry1634004 was because I anticipated a brief +daam/dt period and the models were hinting at that possibility.

It was a great call back then nonetheless, since here we are with another burst of heat that was not clearly on the data back when you posted in early July. The euro ensembles continue to show tendency for troughing in the east in the day 11-15 (this has been going on for like a month straight), and while this hasn't exactly failed at times(we have seen a couple days back towards seasonable with troughs swinging through) the timing has been a real bihotch to nail down, and the warm surges in between have been getting picked up closer to the 6-10 day range...This has lead to difficulties on my part in the 7-14 day forecast period. I've kept it +1 to +3 on average for the MA/NE in that range, but it seems as we get closer there's always a day or 2 all of a sudden that pops in at 95-100 with heat advecting in from the drought regions to make these anomalies verify warmer (especially in the mid-atl)...It appears this is going on again with next week, as late week now looks like there will be another hot surge in the mid-upper 90s...Then the euro ensembles show another trough right through the 11-15 (fool me 8 times, shame on...... :axe: ) Looks to me like a pretty persistent pattern is the way to go heading into August. I'm trying to figure out at what point in August /this summer do things change up a bit and we stop seeing these heat surges reaching the East Coast. Sorry for the non-thunderstorm related rant lol.

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Actually, I mused late last night just how perfectly bad that timing was… It was too early to involved yesterday evening “that far” SE of the forcing, and too late [probably] the next day ...speaking in terms of my region of SNE. Seems things are setting up to make sure that is all the case at least excuse imaginable.

Who knows – maybe the slow movement of the boundary and associated convergence can pay off. I just need the rain desperately.

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MESOSCALE DISCUSSION 1489

NWS STORM PREDICTION CENTER NORMAN OK

0925 AM CDT WED JUL 18 2012

AREAS AFFECTED...MUCH OF PA/NJ TO SOUTHERN NY/SOUTHERN NEW ENGLAND

CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY

VALID 181425Z - 181630Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...WITH INCREASING POTENTIAL FOR DAMAGING WINDS/SEVERE HAIL

THIS AFTERNOON...A SEVERE TSTM WATCH WILL LIKELY BE NEEDED FOR ALL

OR MUCH OF PA/NJ AND SOUTHERN PORTIONS OF NY/NEW ENGLAND BY 15Z-16Z.

DISCUSSION...A FRONTAL BOUNDARY IS ANALYZED THIS MORNING FROM LAKE

ERIE VICINITY EAST-NORTHEASTWARD TO EAST-CENTRAL NY/CENTRAL NEW

ENGLAND. THE AIRMASS TO THE SOUTH OF THIS BOUNDARY IS STEADILY

WARMING AMID RELATIVELY CLOUD-FREE SKIES PER VISIBLE SATELLITE

IMAGERY...WITH DEWPOINTS GENERALLY IN THE UPPER 60S/LOWER 70S F.

INCIPIENT TSTM DEVELOPMENT IS ALREADY OCCURRING ACROSS WEST-CENTRAL

PA AS OF 14Z. ALONG/SOUTH OF THE COLD FRONT...WITH ADDITIONAL AIDE

OF NEAR-COASTAL/PRE-FRONTAL SURFACE TROUGH DEVELOPMENT...IT SEEMS

VERY LIKELY THAT SCATTERED TSTMS WILL CONTINUE TO DEVELOP/INCREASE

INTO EARLY/MID AFTERNOON ACROSS MUCH OF THE REST OF PA/NJ AND

SOUTHERN NY/SOUTHERN NEW ENGLAND.

BASED ON 12Z OBSERVED SOUNDINGS SUCH AS BUF/ALB/OKX...MUCH OF THE

REGION RESIDES ON THE SOUTHERN FRINGE OF MODERATE WESTERLIES ALOFT

/30-50 KT 3-6 KM/ AND COINCIDES WITH A PLUME OF RELATIVELY STEEP MID

LEVEL LAPSE RATES /ESPECIALLY SOUTHEAST NY AND SOUTHERN NEW

ENGLAND/. WITH STEEPENING LOW LEVEL LAPSE RATES AND A LIKELIHOOD OF

2000-3500 J/KG SBCAPE SOUTH OF THE COLD FRONT...STRONG/SEVERE TSTM

DEVELOPMENT AND INTENSIFICATION IS LIKELY THROUGH EARLY/MID

AFTERNOON. SUFFICIENT VERTICAL SHEAR EXISTS FOR ORGANIZED/SUSTAINED

MULTICELLS...AND THIS WILL ESPECIALLY BE THE CASE FOR AREAS SUCH AS

NORTHEAST PA/NORTHERN NJ INTO FAR SOUTHEAST NY/SOUTHERN NEW ENGLAND.

HERE...SOMEWHAT STRONGER VERTICAL SHEAR WILL SUPPORT BOWING

STRUCTURES/SOME SUPERCELLS...WITH DAMAGING WINDS/SEVERE HAIL AND

PERHAPS A TORNADO BEING POSSIBLE.

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Actually, I mused late last night just how perfectly bad that timing was… It was too early to involved yesterday evening “that far” SE of the forcing, and too late [probably] the next day ...speaking in terms of my region of SNE. Seems things are setting up to make sure that is all the case at least excuse imaginable.

Who knows – maybe the slow movement of the boundary and associated convergence can pay off. I just need the rain desperately.

would think an area that may get screwed maybe the portsmouth to nashua to the money pit mike area.

looks like you stil have a couple hour in ayer,mass proll till at least 1pm (of sun) to fire something.

temps/dews are just starting to bake in sne ....20c air from bos pike southward with some 21c plus air in se mass. 19 c from portsmouth to haverhill to fitchburg.

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