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Ju-ply 2026 Obs and Disco - Kicking it off with heat, humidity, and ... severe?

weatherwiz

By weatherwiz,
in New England

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powderfreak
powderfreak

Made it to my grandparents’ homeland… Norwegian family here.  Second time over in Norway, but man, this place is absolute sensory overload. Fun watching the Red Sox win 14 from various airports t

HIPPYVALLEY
HIPPYVALLEY
CT Rain
CT Rain

This is a big/strong signal for big rains.   

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vortex95

vortex95

Posted
Posted
15 hours ago, CoastalWx said:

Still some disagreement, which is no surprise with these cold season synoptics in the warm season. I do think someone’s gonna get dumped on, especially if we have these little embedded meso lows to enhance the rainfall locally.

Something that *really* stands out for this event and why I think 10"+ is likely in some spots.  Let's see if @CoastalWx and @WxWiz know this excessive rainfall rule of thumb! :P

CAPE for a nor'easter is outstanding, esp. for New England.  The entire time for much of cntrl and srn New England, the values are 500-1000.  These are *ideal* values for maxing rainfall rates and droplet collision/coalescence for high rainfall efficiency.  Warm rain process rule.  The CAPE provides additional lift on top of the synoptic-scale lift, but it is not too strong as to push a lot of drops above the freezing layer or at least above -40 C where spontaneous freezing occurs.

So look out!

Also, w/ CAPE present, it is going to be windier, esp. inland, b/c of good mixing of the BL.  And likely a lot tstm activity for a Nor'easter.  This happened on Oct 23-24, 2014.  A lot of tstms and I recall it was windy from the NE even before the rain moved in b/c BL mixing was excellent.  Up to 6" of rain from this event (does CoastalWx recall it?).

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vortex95

vortex95

Posted
Posted
6 hours ago, Damage In Tolland said:

Life threatening ? So much hype 

"Life-threatening" -- most inclement wx is life-threatening in some way.

Why not just "dangerous?"  That is all-inclusive for being injured and a fatality.  Yet we see "extremely dangerous and life-threatening" in the same line en masse now.  Superfluous wording and redundant.  More is not always better. 
 

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vortex95

vortex95

Posted
Posted
5 hours ago, CoastalWx said:

Actually, the 18 nam  was kind of what I pictured yesterday, but I know it’s the nam lol. But it kind of shows you what I was sort of envisioning.

 

I find these events very difficult to predict, you gotta look at synoptics and sort of climatology and try to figure out where the best rain would be and not knee jerk model to model or run to run.

What about the warm front position!!!!  You were all over that and dogmatic last event! LOL.

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WxWatcher007

WxWatcher007

Posted
Posted
2 hours ago, SJonesWX said:

what does this map even mean? Like, there is a slight ~15% chance that I get excessive rainfall? what is excessive? And yes I know it is going to rain

just seems stupid to me

15% chance of an area within 25 miles seeing rainfall that exceeds flash flood guidance. Kind of similar to SPC outlooks of having a certain percentage chance of seeing severe within 50mi or whatever it is. Flash flood guidance varies depending on recent rainfall (among other things, probably). 
 

Caveat is moderate risk on rainfall is not the same as a mod risk for severe. When I see a mod rain risk it’s noteworthy but not uncommon. A high risk is serious though—they almost always precede catastrophic flooding somewhere within the zone. 

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Amped

Amped

Posted
Posted
20 minutes ago, WinterWolf said:

Is that stuff down off NJ and Delaware supposed to rotate up in here? 

It does on the Hrrr, just takes like 8 to 12hrs.

Edit HRRR takes a 996mb low into New Haven this run and 5" for most of Faifield County.

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vortex95

vortex95

Posted
Posted
1 hour ago, Amped said:

It does on the Hrrr, just takes like 8 to 12hrs.

Edit HRRR takes a 996mb low into New Haven this run and 5" for most of Faifield County.

996 mb for a coastal low is quite impressive for July here.  And it's tight little sucker!

Going see some big rain from this esp. since CAPE are 500-1000 over srn New England for most of the event.  Those  are ideal values for max rainfall rates and warm rain processes.

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metagraphica

metagraphica

Posted
Posted
2 hours ago, Amped said:

It does on the Hrrr, just takes like 8 to 12hrs.

Edit HRRR takes a 996mb low into New Haven this run and 5" for most of Faifield County.

 

39 minutes ago, vortex95 said:

996 mb for a coastal low is quite impressive for July here.  And it's tight little sucker!

Going see some big rain from this esp. since CAPE are 500-1000 over srn New England for most of the event.  Those  are ideal values for max rainfall rates and warm rain processes.

 

Screenshot 2026-07-29 022721.jpg

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vortex95

vortex95

Posted
Posted

04z HRRR rides a 996 mb low into cntrl CT (makes "landfall") later this morning.

This is how the BDL F4 occurred on 10/3/1979.  Sfc low from S of LI came up from the S and moving right over cntrl CT. 

Did WxWiz even get a hint of this before going to bed?  I know CoastalWx did not, and now be like, "HUH????, where did this come from?!  I was focused on all the rain!"   :P

Sooo...has anyone looked at the svr wx parameters?  They are sneaky impressive.

From 04z HRRR:

1)
CAPE values NE of the sfc (meso?) low. 500-1000.  That's more than enough when low-level shear is solid (see below).

2)
0-3 km CAPE - areas of 200+ CT/RI border to srn NH - again, more than enough (75 or more is good).

3)
Now this is where it gets interesting.  0-1 km SRH NE of sfc low, large area of 200 w/ a max of 447 at 17z over NW RI!  That is crazy and no reason this is spurious given the set up and evolution here.

4) SCP and SIGTOR area are there.  Not honkin' but that's due to low CAPE largely.  Low CAPE/high shear can do some amazing things!

4) Sim radar shows discrete cells in an arcing line NE of the sfc low.

NE of sfc lows (synoptic, meso, or tropical) are prime areas for spinners.  You have low CAPE in the column, but its more than enough for stout convective updrafts, 0-3 km CAPE is high so there is your low-level vortex stretching, and 0-1 km SRH is excellent.

SPC 06z outlook has gen tstms only for the NE.  I don't know about that. 

And yes, the small low pressure is already there off the NJ coast (radar attached).
 

hrrrsfc.png

hrrrradar.png

 

 

 

 

mucape.png

03c.png

01k.png

scp.png

sigtor.png

radar.png

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