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New England Severe weather thread number ...I think XI ?


OSUmetstud

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The synoptic pattern for the Friday through Sunday shortwave looks ripe for classic EML advection. However, there remains some concern about how much shear will be able to impinge the warm sector. This is certainly a strong and fairly far south shortwave modeled for this time of year...but severe weather in early August is quite tough climatologically.

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The synoptic pattern for the Friday through Sunday shortwave looks ripe for classic EML advection. However, there remains some concern about how much shear will be able to impinge the warm sector. This is certainly a strong and fairly far south shortwave modeled for this time of year...but severe weather in early August is quite tough climatologically.

If it is going to be anyone, it will be your area (Lakes-St. Lawrence sector). The climatology aspect is strongly in the back of my mind as a possible negating factor. As I said before, there hasn't been a significant "Ekster-approved" EML-induced severe weather outbreak between 7/23-8/14 (including the start/end date). While that's not necessarily checkmate, it certainly stems from good reason.

Speaking of Ekster, this event coming up probably wouldn't make it anyway even if it ends up producing SIG SVR in the Northeast. The 700mb setup and EML advection look more like the other data set they produced of SIG SVR events that did not have a well defined EML.

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If it is going to be anyone, it will be your area (Lakes-St. Lawrence sector). The climatology aspect is strongly in the back of my mind as a possible negating factor. As I said before, there hasn't been a significant "Ekster-approved" EML-induced severe weather outbreak between 7/23-8/14 (including the start/end date). While that's not necessarily checkmate, it certainly stems from good reason.

Speaking of Ekster, this event coming up probably wouldn't make it anyway even if it ends up producing SIG SVR in the Northeast. The 700mb setup and EML advection look more like the other data set they produced of SIG SVR events that did not have a well defined EML.

How far west did Mike's EML climo go? I thought he included NYS.

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How far west did Mike's EML climo go? I thought he included NYS.

It does include NYS but I still don't think this weekend would qualify if the current NWP verified.

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It does include NYS but I still don't think this weekend would qualify if the current NWP verified.

Can you or anyone else verify whether 8/9/00 / 8/10/00 qualified as "EML enhanced high-end"? I don't have access to soundings for that day/night. Can't find the link that lists the majority of cases. That night was close to as epic as I have seen around here in my life, all three waves of nighttime svr- esp. the supercell / meso from Dutchess co. NY through PVD co RI.

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Can you or anyone else verify whether 8/9/00 / 8/10/00 qualified as "EML enhanced high-end"? I don't have access to soundings for that day/night. Can't find the link that lists the majority of cases. That night was close to as epic as I have seen around here in my life, all three waves of nighttime svr- esp. the supercell / meso from Dutchess co. NY through PVD co RI.

I do not think that was an EML, but I could be wrong. That was a pure dynamics event. You can check on UWYO weather page.

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Shear was very strong on the 10/00z sounding. Looking at PSU NARR, good height falls and a strong vortmax and seemingly associated left entrance region of jet. I remember that night well. Probably one of the best light shows ever.

Station identifier: CHH

Station number: 74494

Observation time: 000810/1200

Station latitude: 41.66

Station longitude: -69.96

Station elevation: 16.0

Showalter index: -4.89

Lifted index: -2.28

LIFT computed using virtual temperature: -2.52

SWEAT index: 414.00

K index: 41.10

Cross totals index: 26.10

Vertical totals index: 27.70

Totals totals index: 53.80

Convective Available Potential Energy: 164.76

CAPE using virtual temperature: 183.48

Convective Inhibition: -222.72

CINS using virtual temperature: -226.37

Equilibrum Level: 406.88

Equilibrum Level using virtual temperature: 406.50

Level of Free Convection: 654.93

LFCT using virtual temperature: 663.05

Bulk Richardson Number: 2.82

Bulk Richardson Number using CAPV: 3.14

Temp [K] of the Lifted Condensation Level: 291.95

Pres [hPa] of the Lifted Condensation Level: 970.30

Mean mixed layer potential temperature: 294.50

Mean mixed layer mixing ratio: 14.29

1000 hPa to 500 hPa thickness: 5721.00

Precipitable water [mm] for entire sounding: 53.50

081003.png

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D5 outlooked, although primarily for areas west of NE.

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0359 AM CDT WED AUG 01 2012

VALID 041200Z - 091200Z

...DISCUSSION...

THE SPREAD AMONG THE MEMBERS OF THE MEDIUM RANGE ENSEMBLES IS

SIZABLE FROM THE OUTSET OF THE FORECAST PERIOD CONCERNING THE STRONG

SHORT WAVE TROUGH LIKELY TO BE ACCELERATING EAST OF THE CENTRAL

CANADIAN/U.S. BORDER AREA...WITHIN A PERSISTENT BELT OF STRONGER

WESTERLIES. HOWEVER...THERE DOES APPEAR REASONABLE CONSENSUS WITH

REGARD TO THE BASIC TRENDS LIKELY TO IMPACT CONVECTIVE POTENTIAL

ACROSS THE GREAT LAKES INTO THE NORTHEAST... AS CYCLOGENESIS

PROCEEDS ACROSS ONTARIO AND QUEBEC THIS COMING WEEKEND.

ALTHOUGH BETTER LOW-LEVEL MOISTURE INFLOW TO THE DEVELOPING SYSTEM

MAY BEGIN BY SATURDAY...THE MORE SUBSTANTIVE STRENGTHENING OF

SOUTHERLY LOW-LEVEL WARM SECTOR FLOW AND SHEAR MAY BE CONFINED TO

PORTIONS OF ONTARIO TO THE NORTH OF LAKES SUPERIOR AND HURON.

AS DEEPENING OF THE SURFACE LOW CONTINUES ON SUNDAY... STRENGTHENING

OF LOWER AND MID TROPOSPHERIC FLOW FIELDS APPEARS INCREASINGLY

PROBABLE AS FAR SOUTH AS AREAS TO THE EAST OF THE LOWER GREAT

LAKES...PERHAPS THE UPPER OHIO VALLEY. WHILE THIS MAY NOT BE MUCH

MORE THAN 30-40 KT...IT DOES APPEAR THAT LOW-LEVEL MOISTENING AND

STEEPENING OF MID-LEVEL LAPSE RATES WILL BECOME SUFFICIENT FOR THE

DEVELOPMENT OF MODERATELY LARGE CAPE ACROSS MUCH OF NEW

YORK/PENNSYLVANIA AND PORTIONS OF ADJACENT STATES. THIS ENVIRONMENT

APPEARS POTENTIALLY SUPPORTIVE OF AN EVOLVING ORGANIZED MESOSCALE

CONVECTIVE SYSTEM CAPABLE OF PRODUCING CONSIDERABLE DAMAGING WIND

GUSTS...PARTICULARLY AS MID-LEVEL FORCING FOR UPWARD VERTICAL MOTION

BEGINS TO SPREAD EAST OF THE LOWER GREAT LAKES REGION...EITHER LATE

SUNDAY OR SUNDAY NIGHT.

..KERR.. 08/01/2012

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The weekend promises to be, at the very least, interesting. If this period should fail for widespread severe weather, the extended-range pattern looks supportive of additional opportunities for severe weather (in particular late next week).

After warm front woes Saturday, a prefrontal trough at the leading edge of height falls may bust cap Sunday PM. Then, depending on the timing of the front, either late Sunday / early Monday could bring more thunderstorm opportunities. The timing sucks for the coastal plain.

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8/9/00 had great dynamics like Scott said and also 500mb temps were -15C or lower with 500mb temps cooling as night went on. Whe it was a steep mlvl lapse rate environment it was the product of cold mlvl temps...no EML if I recall

there's an EML on the OKX sounding. I checked it out last night when you guys were talking about it.

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there's an EML on the OKX sounding. I checked it out last night when you guys were talking about it.

Yeah the mid level lapse rates are steep from 700-600mb. They warm a bit near 550mb, but couple all that with the forcing, and it was more than enough to force updraft acceleration.

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Yeah the mid level lapse rates are steep from 700-600mb. They warm a bit near 550mb, but couple all that with the forcing, and it was more than enough to force updraft acceleration.

yeah i'd bet 500mb temps were a bit cooler farther north. You can see cold advection/subsidence in the 500mb area on the OKX sounding.

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Despite the GFS blowing up precipitation quickly Sunday, the 18z run looks much better (all QPF issues aside). The EML looks stronger with a notable +10C pocket over NY and there are defined low and mid level wind maximums.

Sunday has potential.

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NY/PA look in good shape for a severe day on Sunday. Timing too slow for us in SNE. Would need everything to speed up at least 6 hours.

I think NY / PA look great and I am thinking this will be a moderate risk day for them with the potential for tornadoes (esp. if we get the degree of SRH 0-1km and LLJ the models currently are showing).

While I agree that the timing sucks for the folks in the coastal plain, I do think this looks like a classic SLT risk day. Anything that can get going ahead of the cold front along the prefrontal trough could certainly go severe.

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I think NY / PA look great and I am thinking this will be a moderate risk day for them with the potential for tornadoes (esp. if we get the degree of SRH 0-1km and LLJ the models currently are showing).

While I agree that the timing sucks for the folks in the coastal plain, I do think this looks like a classic SLT risk day. Anything that can get going ahead of the cold front along the prefrontal trough could certainly go severe.

That should get people talking. :twister::P

I do agree with you though, although I still have concerns over instability potential, and whether morning convection/junk will play into this.

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