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JULY 2012 Severe Weather /Convection Discussion


NEG NAO

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Interesting to see if the models shift south with the threat as has been the trend on other organized events this year.

This. every threat this year that has been organized has shifted south. we'll see what this one does as its not gonna take much for the entire tri-state area to be in the bullseye with this severe weather outbreak potentially

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Nice disco by Upton:

THE MAIN CONCERN ON THURSDAY IS THE POTENTIAL FOR SEVERE WEATHER

THURSDAY AFTERNOON. HAVE 1500-3000 J/KG OF CAPE FORECAST ACROSS

MOST OF THE REGION WITH 500-1500 J/KG OVER THE EASTERN 1/3 (DO NOT

BUY INTO GFS HAVING HIGHER VALUES THAT FAR EAST DUE TO THE

OVERLY PROGRESSIVE/STRONG NATURE OF ITS SOLUTION). MITIGATING

THE LOWER CAPE OVER EASTERN 1/3 IS THAT THE CORE OF A 40-50 KT 950

HPA JET IS FORECAST INTO THAT AREA IN THE AFTERNOON. IN ADDITION

WILL BE IN THE RIGHT REAR QUADRANT OF A 85+ KT UPPER JET...BE

UNDER A LOW LEVEL THETA-E RIDGE AND 35-40 KT OF 0-6KM OF SHEAR.

BULK RICHARDSON NUMBERS OF 15-45 SUPPORT THE IDEA OF SUPERCELLS

AND MULTI-CELLULAR CLUSTERS AS THE MAIN CONVECTIVE MODE.

THE MAIN THREAT WILL BE FROM DAMAGING WINDS...HOWEVER WITH

HELICITY VALUES FORECAST GENERALLY ABOVE 200 M2/S2 AND 0-1KM

ENERGY HELICITY INDEX OF 2 TO 3...AND 0-3KM VORTICITY GENERATION

PARAMETER VALUES OF 0.25 TO 0.5 THERE IS THE POTENTIAL FOR

ISOLATED TORNADOES AS WELL. THE LIMITING FACTOR FOR NOW IS THAT

THE LIFTING CONDENSATION LEVEL IS FORECAST TO BE FROM 1000 TO JUST

UNDER 1500 METERS - WHICH IS AT THE HIGH END OF THAT FOUND TO BE

NEEDED FOR TORNADIC SUPERCELLS.

AT THIS TIME...IT APPEARS THE GREATEST THREAT FOR SEVERE WEATHER WILL

BE FROM SW CT- NYC ON NORTHWEST...BUT THE POTENTIAL EXISTS

THROUGHOUT THE CWA. THE SEVERE THREAT WILL BE HIGHLIGHTED IN THE

HWO - WHICH IS CONSISTENT WITH SPC HAVING THE ENTIRE AREA UNDER A

SLIGHT RISK FOR SEVERE THUNDERSTORMS.

SPC excerpt:

" GIVEN THE

POTENTIAL FOR WIDESPREAD ORGANIZED SEVERE STORMS AN AREA FROM SRN OH

ACROSS MUCH OF WRN/NRN PA INTO CNTRL NY MAY BE UPGRADED TO A

MODERATE CATEGORICAL RISK IN LATER OUTLOOKS."

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I hope we don't end up with a tornado watch, they seem to be the kiss of death for severe chances in this area the last few years.

We all shouldnt be throwing in the towel with this yet as all organized severe weather has had a tendency this year to be south of what was progged to be its original forecasted location. Todays model runs will shed much more light on what our area should expect as far as widespread severe weather. I agree that the threat for possible tornadic activity will most likely be north of us but i cant honestly see us escaping the action tommorow with this setup. Im willing to bet after 2-3 pm tommorow our entite area is gonna start lighting up like a christmas tree. Yes yanksfan27 the tornado watch has really been our kiss of death lately though lol

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I hope we don't end up with a tornado watch, they seem to be the kiss of death for severe chances in this area the last few years.

6/6/10 :axe::bag:

The only ever time that I have laughed at a severe weather bust. It was just so horrific.

Tornado watches covered pretty much the entire NE.

9z SREF is slowly crawling in. Hopefully its better than the 3z which had the best parameters far to our north.

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Define well north? HM in the NE thread seems to think that NNJ, SE NY and much of CT are in the game....

Of course we are still in the game. These things can change drastically.

The NAM still brings an area of storms near NYC tomorrow night after 0z:

f39.gif

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The SREF actually increased severe probs in our area pretty dramatically this run.

Seems like there are 2 triggers. The 1st one is for well north of the area but then the MCS rolls through here tomorrow evening and brings NYC and north into the game.

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A ton of awful information in this thread, our area still looks primed for possible severe tomorrow afternoon and evening. I still believe the MCS will be very close to our area tomorrow morning but the main threat with that is heavy rain with maybe some stronger cells on the southern tail.

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Soundings are still very intense around 00Z tomorrow but the CAPE has come down a ton from last nights run. We are dealing with a complex of storms rolling through here after dark, and we don't know what debris we are going to deal with from the morning MCS. Very complicated setup, especially at H5 still.

120725143346.gif

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2500+ cape is still quite alot for KNYC. The potential is still very much alive for an MCS sunset/after dark to wack NYC and points east and west. And as earthlight stated severe probabilities have gone up noticeably on the latest SREF run so we just gotta let todays models take there course

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2500+ cape is still quite alot for KNYC. The potential is still very much alive for an MCS sunset/after dark to wack NYC and points east and west. And as earthlight stated severe probabilities have gone up noticeably on the latest SREF run so we just gotta let todays models take there course

Didnt say it wasn't, just making an observation.

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Nice conflicting posts in here. :popcorn:

Just wait until the 17:30 SPC update before you draw conclusions.

The confusion was we are talking about 2 separate MCS type events coming through tomorrow. One in the morning and the main player in the evening.

The morning one is well north of the area and into SNE.

The evening one, around 0z, has the MCS very close to NYC on the srefs and the NAM.

Sorry about the confusion. Should have clarified that.

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Nice conflicting posts in here. :popcorn:

Just wait until the 17:30 SPC update before you draw conclusions.

This. Like i said earlier wayyyy to early to start drawing conclusions. We got all of todays model data to go through including our short range models since were just about in there range. No white flag from me yet

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Didnt say it wasn't, just making an observation.

trials i was just stating the cape and understood what you were saying. Wasng badgering you or anything so please dont take it that way. You def have a much better chance of seeing severe storms tommorow in your area so you gotta be excited
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Seems like there are 2 triggers. The 1st one is for well north of the area but then the MCS rolls through here tomorrow evening and brings NYC and north into the game.

The first is the warm front which is expected to trigger widespread elevated convection associated with the WAA north of our area. It is uncertain where the warm front will come to lie but as HM noted, the MCS north of us will actually help our area by increasing the frontogenesis along the warm front (warm on the south side, cool and cooling off due to rain on the north). Plus any rain that occurs before the warm front moves through will help moisten the layer and lower LCL heights for later in the day. The cold front then will help trigger additional convection with that second batch that the NAM is showing riding the baroclinic zone along the front. With the low-level shear locally enhanced there, that would be where to watch for the greatest threat of anything tornadic. As of now the front looks to be just north of our area straddling the NJ/NY border and into NE PA, but that is still fairly close to us especially at this stage. I just wouldn't worry about it being "too far north" just because of the first batch that the NAM is showing. (And this goes without saying, but this is assuming the NAM is even correct about its warm front placement which is a whole other issue...)

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The first is the warm front which is expected to trigger widespread elevated convection associated with the WAA north of our area. It is uncertain where the warm front will come to lie but as HM noted, the MCS north of us will actually help our area by increasing the frontogenesis along the warm front (warm on the south side, cool and cooling off due to rain on the north). Plus any rain that occurs before the warm front moves through will help moisten the layer and lower LCL heights for later in the day. The cold front then will help trigger additional convection with that second batch that the NAM is showing riding the baroclinic zone along the front. With the low-level shear locally enhanced there, that would be where to watch for the greatest threat of anything tornadic. As of now the front looks to be just north of our area straddling the NJ/NY border and into NE PA, but that is still fairly close to us especially at this stage. I just wouldn't worry about it being "too far north" just because of the first batch that the NAM is showing. (And this goes without saying, but this is assuming the NAM is even correct about its warm front placement which is a whole other issue...)

Thanks for the explanation. Great post.

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