Monday, May 16, 2022 Convective Potential

[weatherwiz]

A strong cold front is set to move across New England late Monday. Combination of surface temperatures into the upper 70's to lower 80's and dewpoints into the lower 60's will yield modest levels of instability (MLCAPE ~1000 J/KG) with poor lapse rates limiting further instability. Aloft, a strong shortwave trough rotates across the region resulting in ample wind shear with 700mb winds approaching 40 knots and 500mb winds approaching 60 knots. 

As the cold front encounters the warm and humid airmass, a line of rain and thunderstorms will likely form across NY/PA and propagate southeast into New England. Strong shear will help aid in convection organized. While instability will wane with southeastward extent due to marine flow, strong dynamics aloft may help compensate and allow for the line to continue progressing towards the coast, albeit weakening. 

Given modest CAPE and strong wind shear there will be localized threat for damaging wind gusts. 

By no means a BIG severe threat but something to be excited over, especially knowing the REAL stuff isn't far away.

[radiator]

I always look forward to your heads-up threads about upcoming potential severe WX.

Whether or not they actually materialize, a guy can always hope, can't he?

 

 

[OceanStWx]

4 hours ago, weatherwiz said:

A strong cold front is set to move across New England late Monday. Combination of surface temperatures into the upper 70's to lower 80's and dewpoints into the lower 60's will yield modest levels of instability (MLCAPE ~1000 J/KG) with poor lapse rates limiting further instability. Aloft, a strong shortwave trough rotates across the region resulting in ample wind shear with 700mb winds approaching 40 knots and 500mb winds approaching 60 knots. 

As the cold front encounters the warm and humid airmass, a line of rain and thunderstorms will likely form across NY/PA and propagate southeast into New England. Strong shear will help aid in convection organized. While instability will wane with southeastward extent due to marine flow, strong dynamics aloft may help compensate and allow for the line to continue progressing towards the coast, albeit weakening. 

Given modest CAPE and strong wind shear there will be localized threat for damaging wind gusts. 

By no means a BIG severe threat but something to be excited over, especially knowing the REAL stuff isn't far away.

I'm not sleeping on tomorrow either. Looks more like a straight up and down pulse type event, but I'm interested.

[weatherwiz]

11 hours ago, OceanStWx said:

I'm not sleeping on tomorrow either. Looks more like a straight up and down pulse type event, but I'm interested.

Sometimes these can be fun 

[WxWatcher007]

D3 slight risk for most of the region. 

[Typhoon Tip]

2 hours ago, WxWatcher007 said:

D3 slight risk for most of the region. 

yup...  Not bad for this region considering the lead.  But, that's not claiming much for the competency and climate awareness of the source lol. 

[Torch Tiger]

Don't want to jinx it but looks pretty good for WNE

[Cyclone-68]

Yup some good ones north and west of 495 and le nada inside of 128. Lather rinse repeat 

[Sey-Mour Snow]

[Cyclone-68]

Looks like fun. Just wish I didn’t have to drive to Natick to catch a lightning flash

[weatherwiz]

I'm a bit surprised by the ENH tomorrow. Instability will be limited due to poor mid-level lapse rates. Wind shear will certainly be strong - especially mid-level shear which will help with storm organization and updrafts to become organized, but I don't think llvl shear is overly impressive and we'll have to see how steep llvl lapse rates can get. 

[Modfan2]

Seeing it looks like a decent threat, anyone got some good spots with elevation to chase? Example 

Rt 31 Charlton Ma at Dresser Hill Farm Stand, great view west. 

Town Farm Rd Palmer I also believe has great views west

[DavisStraight]

34 minutes ago, Modfan2 said:

Seeing it looks like a decent threat, anyone got some good spots with elevation to chase? Example 

Rt 31 Charlton Ma at Dresser Hill Farm Stand, great view west. 

Town Farm Rd Palmer I also believe has great views west

Dresser Hill is my spot since Its only 4 miles from my house. Another good spot is the golf course in Charlton.

[Chrisrotary12]

Nice solid t-storm this evening.

[Sey-Mour Snow]

[CoastalWx]

Seems like this will be good into VT as well. Decent support to sustain some activity east of the river too so hopefully some rain. 

[Whineminster]

2% damage chance, I'll take it

[Modfan2]

1 hour ago, CoastalWx said:

Seems like this will be good into VT as well. Decent support to sustain some activity east of the river too so hopefully some rain. 

What is the time frame?

[weatherwiz]

Woah SPC went 45% for wind in eastern PA? Not sure if this setup is one that really favors a widespread significant damaging wind event. Would like to see much steeper low-level lapse rates, stronger llvl flow, and much higher DCAPE values. 

[WxWatcher007]

I was surprised to see that 45% wind too. Hopefully we can at least get a line that holds together near central CT so I can get good vid/pics. 

[Hoth]

We're dawning clear, which normally would make me giddy on a potential severe day. However, given my proximity to the Sound, and the wind likely to be out of the south later, I assume my goose is still cooked for severe chances?

[weatherwiz]

2 minutes ago, Hoth said:

We're dawning clear, which normally would make me giddy on a potential severe day. However, given my proximity to the Sound, and the wind likely to be out of the south later, I assume my goose is still cooked for severe chances?

We do have decent dynamics aloft so that will help compensate some for the marine taint. Severe weather chances will certainly decrease south and east across SNE. I'm still a bit shocked at the 45% wind contour. Also that area of higher probs may even be a bit too far west. Higher potential may be Hudson Valley right into Berkshire/Litchfield/Fairfield County. Still not sold though on a widespread significant damaging wind event. 

[hudsonvalley21]

10 minutes ago, weatherwiz said:

We do have decent dynamics aloft so that will help compensate some for the marine taint. Severe weather chances will certainly decrease south and east across SNE. I'm still a bit shocked at the 45% wind contour. Also that area of higher probs may even be a bit too far west. Higher potential may be Hudson Valley right into Berkshire/Litchfield/Fairfield County. Still not sold though on a widespread significant damaging wind event. 

In my region to your west, the north/south running valleys should keep an eye out for the discrete cells that form in front the linear action. 

[weatherwiz]

1 minute ago, hudsonvalley21 said:

In my region to your west, the north/south running valleys should keep an eye out for the discrete cells that form in front the linear action. 

agreed

[CT Rain]

Looks pretty good to me WOR. I think there's definitely a tornado threat W CT and Hudson Valley as wind fields increase later this afternoon and surface winds remain backed a bit. 

[weatherwiz]

3 minutes ago, CT Rain said:

Looks pretty good to me WOR. I think there's definitely a tornado threat W CT and Hudson Valley as wind fields increase later this afternoon and surface winds remain backed a bit. 

Models do show >100 J 3km CAPE WOR too later on but models also rapidly begin to diminish CAPE moving through the late afternoon. May not see any discrete cells but even a broken line of storms would need to be watched for rotation in the line breaks. 

[weatherwiz]

I would have also loved to see an observed sounding from OKX. Helium shortage must still be a thing I'm guessing. 

[WhiteLawns]

@CT Rain @weatherwizcan you point me in the direction of some links or books that explain the development of severe storms/supercells/tornados?

[weatherwiz]

1 minute ago, WhiteLawns said:

@CT Rain @weatherwizcan you point me in the direction of some links or books that explain the development of severe storms/supercells/tornados?

In a nutshell this is what you want to look for

1) Lift (cold front or pre-frontal trough for example) 

2) Rich low-level moisture (sfc dewpoints > 60-65 and sufficient moisture through the lowest 5,000-7,000 feet)

3) Instability (to fuel thunderstorms) 

4) Wind shear (to help with updraft strength and organization)

There are plenty of links I can send along later. There are plenty of parameters which can be assessed when determining the potential for convection and severe convection. While parameters are certainly helpful to look at and can give a great idea, everything needs to be factored together. Perhaps one of the more overlooked aspects of convective forecasting involves your lift/forcing. You can have 5,000 J/KG of CAPE but if your lift/shear suck it's going to be tough to get widespread severe weather. Meanwhile, you can have 1200 J/KG and tons of shear and get significant events. 

[WhiteLawns]

6 minutes ago, weatherwiz said:

In a nutshell this is what you want to look for

1) Lift (cold front or pre-frontal trough for example) 

2) Rich low-level moisture (sfc dewpoints > 60-65 and sufficient moisture through the lowest 5,000-7,000 feet)

3) Instability (to fuel thunderstorms) 

4) Wind shear (to help with updraft strength and organization)

There are plenty of links I can send along later. There are plenty of parameters which can be assessed when determining the potential for convection and severe convection. While parameters are certainly helpful to look at and can give a great idea, everything needs to be factored together. Perhaps one of the more overlooked aspects of convective forecasting involves your lift/forcing. You can have 5,000 J/KG of CAPE but if your lift/shear suck it's going to be tough to get widespread severe weather. Meanwhile, you can have 1200 J/KG and tons of shear and get significant events. 

Thank you sir! I just want to have a better understanding of the forces at play. I hurt my back so all I’ve been doing for the last two weeks is trying to learn stuff to distract me from the pain lol.