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Severe weather potential friday 7/29


earthlight

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The forecast models have honed in on the potential for a severe weather event on Friday throughout the Northeast States. A surface low is forecast to dive southeast in response to a shortwave and vorticity max currently located over the Western Great Lakes. In response to this feature, kinematic support will increase throughout the day on Friday. In fact, the NAM has a widespread area of of 0-500mb bulk shear over 40 kts with isolated values over 50 to near 60 kts by 21z on Friday

ZcIc1.png

In addition, there is quite a bit of low level shear evident on forecast soundings throughout the Northeast. This is especially true over New England, closer to the surface low, but is even evident as far south as the Northern Mid-Atlantic towards Central New Jersey. This is confirmed on the graphical forecast 0-3km helicity parameters, with values in excess of 200-250 m2/s2 forecast over New Jersey and New York, increasing to 300-400 m2/s2 over New York State and New England.

Fc2GY.png

The forecast models also have a moderately to severely unstable environment (probably more severely unstable given the degree of shear and forcing present in the environment) in place by the afternoon across the area...with surface cape values over 2000 joules. This instability is a bit less to our north--where the better shear is--and a bit higher to our south, although they lack the better kinematics.

With the degree of forcing for ascent being dramatically increased with the shortwave and surface low in the vicinity, the potential certainly exists for a widespread convective event Friday afternoon and evening throughout the Northeast states. The juxtaposition of kinematic and thermodynamic support seems to be best over a small area from New York State moving southeast into Western SNE by evening--and it is here that I would not be surprised to see a few tornadoes.

Otherwise--damaging wind reports could be widespread if the forecast models interpretation of the synoptic setup is correct. The SPC WRF from 12z today confirms this...with widespread discrete updrafts and multicellular clusters affecting the northeast states by tomorrow afternoon.

refd_1000m_f36.gif

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The forecast models have honed in on the potential for a severe weather event on Friday throughout the Northeast States. A surface low is forecast to dive southeast in response to a shortwave and vorticity max currently located over the Western Great Lakes. In response to this feature, kinematic support will increase throughout the day on Friday. In fact, the NAM has a widespread area of of 0-500mb bulk shear over 40 kts with isolated values over 50 to near 60 kts by 21z on Friday

In addition, there is quite a bit of low level shear evident on forecast soundings throughout the Northeast. This is especially true over New England, closer to the surface low, but is even evident as far south as the Northern Mid-Atlantic towards Central New Jersey. This is confirmed on the graphical forecast 0-3km helicity parameters, with values in excess of 200-250 m2/s2 forecast over New Jersey and New York, increasing to 300-400 m2/s2 over New York State and New England.

The forecast models also have a moderately to severely unstable environment (probably more severely unstable given the degree of shear and forcing present in the environment) in place by the afternoon across the area...with surface cape values over 2000 joules. This instability is a bit less to our north--where the better shear is--and a bit higher to our south, although they lack the better kinematics.

With the degree of forcing for ascent being dramatically increased with the shortwave and surface low in the vicinity, the potential certainly exists for a widespread convective event Friday afternoon and evening throughout the Northeast states. The juxtaposition of kinematic and thermodynamic support seems to be best over a small area from New York State moving southeast into Western SNE by evening--and it is here that I would not be surprised to see a few tornadoes.

Otherwise--damaging wind reports could be widespread if the forecast models interpretation of the synoptic setup is correct. The SPC WRF from 12z today confirms this...with widespread discrete updrafts and multicellular clusters affecting the northeast states by tomorrow afternoon.

Wow! Great forecast and read earthlight always enjoy reading your forecasts.....as for the potential tommorow there is def a good chance of seeing a decent severe weather outbreak especially away from the coast as you stated I'm more concerned of having a situation a few months ago where we under that tornado watch and were forecast to see severe/tornadic outbreak only to see the good stuff happen into new england and us being given a few discete cells. This set up is probably different than that though but until tommorow afternoon I'm not gonna put my eggs in any basket as far as severe weather potential that's my take lol

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There is always an "if" with severe weather, which is an incredible process to begin with. That's why forecasting these types of things can be so challenging and humbling.

That's what makes weather so interesting to me the fact that so many factors have to be aligned for a weather event to happen a certain way its always fascinated me how challenging it is and how difficult it is to ever put out an accurate forecast together especially for a severe weather scenario

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SPC seems to agree with the idea of a localized tornado threat near the juxtaposition of low level shear and moderate instability, as well as the general threat we are discussing.

...NORTHEAST...

BOTH SHEAR AND FORCING FOR ASCENT ARE FORECAST TO STRENGTHEN AND

SUPPORT INCREASINGLY ORGANIZED TSTMS ASSOCIATED WITH THE UPPER

TROUGH AND WEAK SURFACE LOW DEVELOPING ACROSS NY DURING THE DAY.

SUFFICIENT DESTABILIZATION IS EXPECTED TO OCCUR FROM NERN PA AND NRN

NJ ACROSS THE LOWER HUDSON VALLEY...AND POSSIBLY INTO SWRN NEW

ENGLAND...FOR A FEW SEVERE STORMS. IN ADDITION TO HAIL AND SOME

DAMAGING WIND POTENTIAL...GREATER LOW LEVEL SHEAR NEAR THE SURFACE

LOW WOULD ENHANCE THE POSSIBILITY OF A TORNADO OR TWO IF STRONGER

DESTABILIZATION CAN OCCUR COINCIDENT WITH THE PASSAGE OF THE LOW.

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The new 15z SPC SREF continue to show the potential for a widespread convective event. They're also continuing to focus on an area from New York State into West-Southwest Connecticut tomorrow afternoon and evening where the threat could be maximized--with the potential for severe winds and tornadoes.

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AFD out of Upton:

MODEL TRENDS SHOW AN MCS DEVELOPING ALONG A WAVE OF LOW PRESSURE AND A STRENGTHENING LLJ THAT PASSES ALONG THE FRONT AND NORTH OF THE REGION. GFS/ECMWF FAVOR A MORE NORTHERN TRACK...WHILE NAM FAVORS A SOUTHERN TRACK THAT WOULD DEVELOP THE MCS DIRECTLY OVER THE FORECAST AREA. THE REGION CONTINUES TO BE IN A SLIGHT RISK OF SEVERE TSTMS PER SPC...WITH DAMAGING WINDS BEING THE GREATEST THREAT.

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Wait has blizzard09 gotten I good storm this summer so far?

Um no let me explain what happens to me where I live on long island this year....the storms form inland they become strong and severe really put on a good show and then when they get to the coast they die and I get a "garden variety" thunderstorm if that sometime but nothing too exciting like winds, small hail, awesome lightning show and loud ass thunder, nope not me just a regular thunderstorm haha....but just maybe just maybe I might get lucky tommorow and get one......or not lol

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Um no let me explain what happens to me where I live on long island this year....the storms form inland they become strong and severe really put on a good show and then when they get to the coast they die and I get a "garden variety" thunderstorm if that sometime but nothing too exciting like winds, small hail, awesome lightning show and loud ass thunder, nope not me just a regular thunderstorm haha....but just maybe just maybe I might get lucky tommorow and get one......or not lol

And I thought I had seen the longest run on sentence ever.

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And I thought I had seen the longest run on sentence ever.

Somebody else does that too but I haven't seen him post in a while. Run ons drive me crazy. I read it as written and in my head I sound like an idiot.

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And I thought I had seen the longest run on sentence ever.

Nope now i have until someone else comes and steals that honor from me hahaha. My statement does hold some merit though being that living on the coast is the absolute worst place for severe weather compared to let's say.....you lol

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00z NAM demolishes NYC (I feel like I'm talking snow)..intense convective squall propagating NW to SE through NNJ around 00z-03z.

Forky and I were just texting and it was funny how it reminded me of winter...stuff like "how is the nam?"...."kills us"...and all that.

anyway, yeah it's a monster hit. it's been showing the goods for several runs now with tremendous shear, well timed forcing, low level backing and 0-3km velocity values that are very impressive. they've actually increased on this 00z run...we will have to see if it's got the right idea. if it does, we could be in for something big tomorrow.

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Forky and I were just texting and it was funny how it reminded me of winter...stuff like "how is the nam?"...."kills us"...and all that.

anyway, yeah it's a monster hit. it's been showing the goods for several runs now with tremendous shear, well timed forcing, low level backing and 0-3km velocity values that are very impressive. they've actually increased on this 00z run...we will have to see if it's got the right idea. if it does, we could be in for something big tomorrow.

Yeah unfortunately being in the bullseye 12-24 hrs out means a lot less with svr than it does with snow, but either way, I agree the parameters are pretty conducive tomorrow for strong storms. Bows/lines producing wind damage probably the primary threat given impressive shear. Maybe some isolated spin-ups out ahead of the line as those EHI values are fairly high.

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And of course I'll be busy tomorrow night, out with friends like a 'normal' person while deep down I'd rather be parked in front of my GRLevel3 and awaiting updates with bated breath. :arrowhead:

I'll be out too, but luckily radarscope was invented. One of gods great gifts.

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Going to be a lot of clouds in and around the city and on the coast, not sure how much this area clears out, if at all. Further W and N&W should clear out into the Hudson Valley NW Jersey. 6Z NAM couldnt look more different from the 00z stormagedon, so 12z will be interesting.

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