Low pressure west of the Azores (Is Invest 96L)

[MarioProtVI]

This is a system that has been on the models for several days now and appears to be undergoing STCG by transitioning. However the NHC for whatever reason has refused to mark it despite some solid model support and the precursor actually existing. Wanted to make a thread to discuss it since I haven’t seen it posted anywhere else yet.

[underthwx]

This is a system that has been on the models for several days now and appears to be undergoing STCG by transitioning. However the NHC for whatever reason has refused to mark it despite some solid model support and the precursor actually existing. Wanted to make a thread to discuss it since I haven’t seen it posted anywhere else yet.

https://media.discordapp.net/attachments/857017650042503178/1301530407480721510/image0.png?ex=6724d026&is=67237ea6&hm=d4f45fb2efef2ee00a6941a1d82f588cab1c8fd0e7b3c0d95a75b1dcacebf027&
https://cdn.discordapp.com/attachments/1052378176732540979/1301560243351715900/IMG_1949.gif?ex=6724ebef&is=67239a6f&hm=155d2e121295750dbbe5d249e8477c05e19fbd0d98ac3d45a27d98062f2603eb&

Great satellite loop!. Definitely looking as if it's trying to get organized. I think the NHC is biding it's time on this system, they have the luxury of time and expertise, as we all know and rely on. I think ar a minimum a TD may eventually form from this, maybe meander around a bit, but beyond that, remains to be seen.

[TheAustinMan]

I'm surprised this doesn't have at least a low-probability marking on the NHC Tropical Weather Outlook. These sorts of high-latitude developments with smaller-scale circulations centrally nestled within a broader upper-level trough tend to overperform, and it wouldn't shock me at all to see actually develop central convection and, yes, perhaps even an eye (or "eye feature") of some sort as these systems are wont to do once warm-seclusion occurs sometime tomorrow. That sounds like a very bold claim given the current state of the storm, but in fact the CMC, GFS, and even the ECMWF have shown this sort of thing to varying degrees tomorrow or Saturday. The tropopause is a bit lower and thus warmer than the types of environments that typically favor this manner of development, which could put a damper on convective intensity and limit the depth of the warm core, making for a more shallow system. I'd normally like to see a 80C difference between the 200hPa temperature and SSTs (as exemplified by 2016's Hurricane Alex), but the tropopause appears to be hanging out at about 300hPa with a 65C temperature difference between that layer and the sea. Still, could be an interesting thing to monitor and could be a neat display of high-latitude development.

[Pasmorade]

North Atlantic:
Showers and thunderstorms have developed near the center of a
storm-force non-tropical low pressure area located about 550 miles
west of the western Azores. However, any additional development into
a subtropical or tropical cyclone is expected to be slow to occur as
the system moves eastward during the next few days. Additional
information on this system is available in High Seas Forecasts
issued by the National Weather Service.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...20 percent.

[WaveBreaking]

About to cut off from the occluded front.

[cycloneye]

North Atlantic:
A storm-force non-tropical low pressure area located about 500
miles west of the western Azores is producing limited shower
activity. Some subtropical development is possible while the low
moves generally eastward during the next few days. Additional
information on this system is available in High Seas Forecasts
issued by the National Weather Service.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...20 percent.

[TheAustinMan]

As anticipated, the low pressure system is evolving quickly after having occluded. Weak to moderate convective activity should continue overnight, and we may be seeing some sort of eye or eye-feature tomorrow should the global guidance pan out. The storm could bring some gusty winds to the Azores Saturday into Sunday, so I would not be surprised if this gets an INVEST designation soon, commensurate with the improved organization.

Source: AWIPS CAVE

[WaveBreaking]

This’ll probably be Patty soon

[WaveBreaking]

As of 00Z last night, the low was still connected to an occluded front according to Met Office. I’m sure the 06Z update will probably show further decay or no fronts connected to the low.

[cycloneye]

Impressive.

[tolakram]

Some posts removed ....

Mind boggling, what's next, .... more NHC bashing. As was warned in the other thread, give your opinions about a storm and leave the bashing out or you will be gone. I'm not sure how to phrase that politely. You can certainly express your opinion on this disturbance / storm and how you would classify it. It's not that hard to leave the bashing out of posts.

[TheAustinMan]

Largely extratropical, but gradually looking more subtropical in character. Additional detachment from fronts could aid in that transition, as this morning's scatterometer suggested that frontal structures were still close to the small region of organized convection. The strongest winds were in the 40-45kt range and located within the band of convection surrounding the center of circulation.

Source: GOES MSFC, but colorized by myself.

[cycloneye]

North Atlantic:
A low pressure system located a few hundred miles west of the Azores
has been producing increased convection near its center over the
past few hours. Earlier satellite derived wind data depicted winds
to storm-force mainly to the south of the the center.
Environmental conditions appear favorable for some additional
development and the system could become a subtropical or tropical
storm as it moves generally eastward during the next few days.
Interest in the Azores should monitor the progress of this system.
Additional information on this system is available in High Seas
Forecasts issued by the National Weather Service.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...40 percent.

[WaveBreaking]

[Sciencerocks]

Reminds me of the perfect storm 1991 or Grace https://en.wikipedia.org/wiki/Tropical_ ... race_(2009) of a few years ago. I agree that it is probably a subtropical storm.

[cycloneye]

Invest 96L is up