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weatherwiz

Widespread Severe Wx Saturday, July 20, 2019 across NNE

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Great combination of high temperatures, dewpoints, steep lapse rates, and wind shear look to become juxtaposed across northern New England late Saturday. While you would think timing may become a concern, extreme instability looks to remain in place well into the overnight hours. Forecast models indicate a potential MCS developing...or re-energizing as it rides over the crest of the ridge. Wind shear will be more than supportive for organized and sustaining updrafts. Looks like a signal for a widespread damaging wind event may be unfolding. 

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I don't see anywhere across the US outlooked for Saturday (Day 4) on SPC... don't even mention NE at all anyway lol

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Better chance Sunday i think, Unless the trough gets here quicker the forecasted.

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Could be some cap issues Sat, but maybe NNE can get something going on that theta-e gradient.

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NWS BOX throwing out the D word in their latest discussion. SPC still doesn't have us highlighted at all yet.

Friday through Sunday ...

Hot and humid. H85 temperatures around +20-22C, H7 around +10-12C.
But concern. Steep mid-level lapse rates around Saturday, a lot of
low-level instability. Shear vectors and orientation that suggest
that if something were to become organized over Michigan within the
region of steep mid level lapse rates and advect that perhaps we
could see MCS / derecho activity Saturday and Sunday. Initial
thinking, but nothing set in stone. Initial indications per 17.12z
NAM and 17.0z EC, but not much indication in SREF / GFS. It would
subsequently impact 2m temperature with cloud cover altering the
heat and humidity forecast. Typically when we get the heat and
humidity where highs alone approach triple digits do we see via
climatology MCS / derecho events. Continued forecast of mid to
upper 90 highs, some locations at or just slightly above 100
with dewpoints in the low 70s as boundary layer moisture is
trapped beneath the cap, fueled by S flow, yielding heat indices
around the triple digits, for some locations at or above 110F.
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Yeah, talked about this last week/two weeks. Derecho? More likely sw of NE. However most of NE should have a shot at some more severe wx whether it is mcs related or forcing from prefrontal trough or cfp. I think the better shot of mcs would be NY PA maybe WNE

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9 hours ago, dendrite said:

Could be some cap issues Sat, but maybe NNE can get something going on that theta-e gradient.

H7 temps >+12-13...even seeing +14C on the GFS...that's pretty damn strong 

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Signals are still there for a rather significant event. Obviously the capping is an issue, but it's not like we're looking for initiation...the convection will already initiated and will be moving in from SE Canada. Heights do begin to fall during the evening and forcing slightly increases as the trough moves into SE Canada. 

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I've edited to include Sunday as severe weather potential increases across the remainder of the region. Biggest threat again for damaging winds in association with a line..perhaps multiple. 

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So has this switched to more of a Sunday thing ...  seems this threads opener describes Sunday more succinctly - 

Saturday one would think we are capped and searing ... exclusively.  

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I am still a bit shocked there isn't some risk area across NNE for tomorrow. I totally understand it's capped, but we're not looking for convection to develop...it's going to already be in place and arriving from the W or WNW. Could be a rather nasty MCS trucking through tomorrow night up north. 

We are big time capped Sunday too, but looks like there is some room to weaken that Sunday evening and we get stuff to fire off..don't know how widespread but whatever develops could be quite significant. 

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Looks like Monday could feature widespread action...though we may have lost the best ingredients for a big event 

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31 minutes ago, weatherwiz said:

Looks like Monday could feature widespread action...though we may have lost the best ingredients for a big event 

Is this still NNE wiz or throughout ?

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1 hour ago, OceanStWx said:

CAMs are pretty meh overall, but I'm a little curious what this anomalous jet streak might do. 

I am a little perplexed that MCS sort of fizzles like the models show. 

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CAMS have been all over the place. Still don't seem to have a good handle of the derecho out west as it heads towards NNE. I still think there could be issues tonight up in NY/NNE.

18z NAM NEST goes wild down here too over the next few hours lol

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26 minutes ago, weatherwiz said:

CAMS have been all over the place. Still don't seem to have a good handle of the derecho out west as it heads towards NNE. I still think there could be issues tonight up in NY/NNE.

18z NAM NEST goes wild down here too over the next few hours lol

I'm interested in this stuff in Quebec now, although it does stabilize fairly quickly as you move from VT into NH. You can see the Cu field basically nonexistent across the GYX CWA right now. 

But I'm very interested in CAMs insisting on some sort of MCS moving through around 12z tomorrow morning. 

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3 minutes ago, OceanStWx said:

I'm interested in this stuff in Quebec now, although it does stabilize fairly quickly as you move from VT into NH. You can see the Cu field basically nonexistent across the GYX CWA right now. 

But I'm very interested in CAMs insisting on some sort of MCS moving through around 12z tomorrow morning. 

It does look like we get a llvl jet max moving through between 6-12z with some decent height falls. 

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This has been getting delayed...

As it stands now, inside the day-4 Euro's wheel house and the front is slowed enough that given any sunshine at all Monday morning and we pop back up over 90 real quick S of VT/NH borders down here... With frontal drap also stalled as S/W digs into the Lakes... that day is becoming a bigger player.  

Tomorrow ( Sunday ) may still rock and roll.. We just have pig SB CAPE so any kind of Lake front/breeze boundary triggers or oreographic assisted hole punches will probably do what is happening now actually...with windy cells ripping down the Mohawk Trail...

But, the systemic lift and jet mechanical stuff occurs with EML slipping away and we could have problems on Monday. 

18 z MAV (GFS MOS) came in over 80 F south of Rt 2 ...so I suspect the GFS cluster is slowly coming around to belaying fropa, too.  

Just some modeling observations to consider -

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