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Northeast Severe/Convective/Thunder thread III


CoastalWx

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Ryan Frederick Hanrahan... What do you think for tomorrow?

Wrong.

Widespread convection... some flirt with severe limits. Definitely not high-end but hopefully good light show and some good heavy rain.

As for Monday... Euro says total fail with early fropa.

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Well today should be fun as there will be a great deal of t'storms around but severe wx will likely be on the more isolated side of things. What a waste of heat/humidity.

Anyways Monday still looks interesting although not quite a setup that would probably produce widespread severe wx either, however, if a few cells can become mature enough and tap into the decent shear they could produce something fun.

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I'm going to work probably 9-6 today but I'm just doing random things. I have to start/finish sharpening the hockey skates today which I estimate should take around 3.5 hours or so then I have to setup stuff to get ready for camp on Monday so if any storms happen to hit while I'm working I'll at least be able to go outside and enjoy them!

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I'll be happy today if I get a couple of good light shows or some nice loud thunder. I am keeping my expectations very low today. I agree with wiz that this is a waste of heat/humidity.

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Not too shabby when you have these numbers at 9 AM:

SBcape about 1000-2000 J/kG (even higher across NJ)

MLcape about 500-1000 J/KG

MUcape 1000-2000 J/KG (even higher across NJ)

LI values of -3C to -4C

0-6km shear values are 30 knots and there actually is a great deal of it which is just off to our west and appears to be a little ahead than modeled.

One thing I don't like though is 925/850mb winds are W/NW...I thought models had them more from SW (maybe they will eventually turn) but this would reduce convergence along the pre-frontal trough/cold front/.

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Kevin is expecting widespread damage.

Ha. In some town today, I am sure that they will see "widespread damage."

Not too shabby when you have these numbers at 9 AM:

SBcape about 1000-2000 J/kG (even higher across NJ)

MLcape about 500-1000 J/KG

MUcape 1000-2000 J/KG (even higher across NJ)

LI values of -3C to -4C

0-6km shear values are 30 knots and there actually is a great deal of it which is just off to our west and appears to be a little ahead than modeled.

One thing I don't like though is 925/850mb winds are W/NW...I thought models had them more from SW (maybe they will eventually turn) but this would reduce convergence along the pre-frontal trough/cold front/.

Numerous thunderstorms a good possibility Low level winds and how this manifests across the northern Mid Atlantic will be interesting for sure. A distinct boundary exists across NJ at the moment.

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Ha. In some town today, I am sure that they will see "widespread damage."

Numerous thunderstorms a good possibility Low level winds and how this manifests across the northern Mid Atlantic will be interesting for sure. A distinct boundary exists across NJ at the moment.

At least with high MUcape values there should be lots of CG lightning.

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Ha. In some town today, I am sure that they will see "widespread damage."

Numerous thunderstorms a good possibility Low level winds and how this manifests across the northern Mid Atlantic will be interesting for sure. A distinct boundary exists across NJ at the moment.

Yeah I think widespread storms (and maybe even a few rounds of them) are a good bet. Sig severe or widespread severe is unlikely.

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SPC upgraded just CT to slight risk

...MID ATLANTIC/NORTHEAST...

A BREAK FROM THE RECENT HEAT IN THE EAST WILL EVENTUALLY COME IN THE

FORM OF A WEAK COLD FRONT THAT WILL CROSS THE APPALACHIANS TODAY AND

MOVE OFF THE MID ATLANTIC SEABOARD BY EARLY SATURDAY. A VERY MOIST

AND INCREASINGLY UNSTABLE AIR MASS WILL PRECEDE THE FRONT THIS

AFTERNOON WITH SBCAPE LIKELY TO EXCEED 2000 J/KG FROM NC TO NYC.

TSTMS SHOULD BECOME MORE COMMON AS CONVECTIVE TEMPERATURES ARE

BREACHED EARLY AND LIFT WITH THE FRONT AND UPPER TROUGH SPREADS EAST

ACROSS THE SPINE OF THE APPALACHIANS.

EFFECTIVE SHEAR MAGNITUDES COINCIDENT WITH THE DEVELOPING CONVECTION

ARE FORECAST TO REMAIN GENERALLY UNDER 30KT. THUS...EXPECT

MULTICELLULAR STORMS WITH UPDRAFTS OCCASIONALLY BECOMING BETTER

ORGANIZED OR PERSISTING IN THE PRESENCE OF POCKETS OF STRONGER

INSTABILITY AND/OR POSITIVE STORM/BOUNDARY INTERACTIONS. BRIEF

EXTREME RAINFALL AND WET MICROBURSTS WITH SCATTERED DAMAGING WINDS

SHOULD BE THE PRIMARY HAZARDS FROM THIS ACTIVITY

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At least with high MUcape values there should be lots of CG lightning.

Overall, your statement is true most of the time, especially with the deep layer CAPE we will have today. However, don't always assume the MUCAPE will be a good indicator because it only takes the most unstable parcel.

Several papers have documented what to look for but here is a quick list:

1) LCL at or warmer than -10°C (more likely to have supercooled droplets)

2) EL at or colder than -20°C (more likely that cloud top is above the charge reversal temp zone)

3) Sufficient CAPE (allowing for updraft speeds of 6 m/s or greater) in the lower mixed phase region of the cloud (mixed phase is -10 to -40°C so lower end is at or warmer than -20°C let's say).

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SPC upgraded just CT to slight risk

...MID ATLANTIC/NORTHEAST...

A BREAK FROM THE RECENT HEAT IN THE EAST WILL EVENTUALLY COME IN THE

FORM OF A WEAK COLD FRONT THAT WILL CROSS THE APPALACHIANS TODAY AND

MOVE OFF THE MID ATLANTIC SEABOARD BY EARLY SATURDAY. A VERY MOIST

AND INCREASINGLY UNSTABLE AIR MASS WILL PRECEDE THE FRONT THIS

AFTERNOON WITH SBCAPE LIKELY TO EXCEED 2000 J/KG FROM NC TO NYC.

TSTMS SHOULD BECOME MORE COMMON AS CONVECTIVE TEMPERATURES ARE

BREACHED EARLY AND LIFT WITH THE FRONT AND UPPER TROUGH SPREADS EAST

ACROSS THE SPINE OF THE APPALACHIANS.

EFFECTIVE SHEAR MAGNITUDES COINCIDENT WITH THE DEVELOPING CONVECTION

ARE FORECAST TO REMAIN GENERALLY UNDER 30KT. THUS...EXPECT

MULTICELLULAR STORMS WITH UPDRAFTS OCCASIONALLY BECOMING BETTER

ORGANIZED OR PERSISTING IN THE PRESENCE OF POCKETS OF STRONGER

INSTABILITY AND/OR POSITIVE STORM/BOUNDARY INTERACTIONS. BRIEF

EXTREME RAINFALL AND WET MICROBURSTS WITH SCATTERED DAMAGING WINDS

SHOULD BE THE PRIMARY HAZARDS FROM THIS ACTIVITY

Perfect outlook; Could not agree more.

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Overall, your statement is true most of the time, especially with the deep layer CAPE we will have today. However, don't always assume the MUCAPE will be a good indicator because it only takes the most unstable parcel.

Several papers have documented what to look for but here is a quick list:

1) LCL at or greater than -10°C (more likely to have supercooled droplets)

2) EL at or below -20°C (more likely that cloud top is above the charge reversal temp zone)

3) Sufficient CAPE (allowing for updraft speeds of 6 m/s or greater) in the lower mixed phase region of the cloud (mixed phase is -10 to -40°C so lower end is below -20°C let's say).

should this be +10ºC? -10 is a pretty chilly LCL for a t-storm day

edit: Ehh not really I guess..

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should this be +10ºC? -10 is a pretty chilly LCL for a t-storm day

The numbers are correct; they are just general guidelines for determining the potential for CG lightning year-round. There is no question today all criteria is met. So yes, you can simplify days like today with simply looking at a CAPE parameter. I just wanted to make sure he doesn't always do that for determining CG potential.

LCL temps will be +12 to +18 today easy

EL temps will be well well well below -20 (like -40 or lower).

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The numbers are correct; they are just general guidelines for determining the potential for CG lightning year-round. There is no question today all criteria is met. So yes, you can simplify days like today with simply looking at a CAPE parameter. I just wanted to make sure he doesn't always do that for determining CG potential.

LCL temps will be +12 to +18 today easy

EL temps will be well well well below -20 (like -40 or lower).

Gotcha. thanks man.

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The numbers are correct; they are just general guidelines for determining the potential for CG lightning year-round. There is no question today all criteria is met. So yes, you can simplify days like today with simply looking at a CAPE parameter. I just wanted to make sure he doesn't always do that for determining CG potential.

LCL temps will be +12 to +18 today easy

EL temps will be well well well below -20 (like -40 or lower).

LCL less than -10? That's not right.

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