ATL: ANDREA - Remnants

[cycloneye]

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sun May 19 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. An area of low pressure is expected to form by Monday several
hundred miles southwest of Bermuda. This system could develop into a
short-lived tropical or subtropical cyclone late Monday or Tuesday
while moving northward or northeastward. Environmental conditions
are expected to become unfavorable for further development by
Wednesday. The next Special Tropical Weather Outlook will be issued
by 2 PM EDT today.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Blake

As of 12:00 UTC May 19, 2019:

Location: 24.0°N 68.0°W
Maximum Winds: 20 kt Gusts: N/A
Minimum Central Pressure: 1016 mb
Environmental Pressure: 1017 mb
Radius of Circulation: 120 NM
Radius of Maximum Wind: 90 NM



Thread that was the topic for this area at Talking Tropics forum.

viewtopic.php?f=31&t=120274&p=2741513#p2741513

[AJC3]

:uarrow: Yep, 50kts of southwesterly shear is kicking its butt!

https://s3.gifyu.com/images/C06176C2-42B3-4036-B483-2B39AFA32DBE.gif

I wanted to bring this post over here to re-emphasize a point about BI and BE systems like this one.

And that's this: Shear really isn't "kicking its butt".

What's causing all that shear is actually what will cause the lowering of pressures. It's 50 knots of highly divergent shear on the eastern flank of the large mid-upper level gyre that will be consolidating over the Bahamas. Make no mistake...if you don't have that 50 knot jet streak out there in mid-May, then that low is not going to form without the baroclinic enhancement that it's providing.

In short, with BI/BE systems, we need to look beyond the traditional "low-shear environment" paradigm that we normally want to see purely tropical development. Another way of saying this is: Don't discuss systems such as these with the mindset that they are "tropical" disturbances, because they're not. Think of them, in part or whole, as baroclinic, or non-tropical entities. This will keep you from getting "tropical myopia", as I like to call it.

[Cypresso]

Most informative post. Thanks for bringing it over.

[cycloneye]

Recon for Monday if necesarry.

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
125 PM EDT Sun May 19 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

An area of low pressure is expected to form by Monday several
hundred miles southwest of Bermuda. This system could develop into a
short-lived subtropical or tropical cyclone late Monday or Tuesday
while moving northward or northeastward. Environmental conditions
are expected to become unfavorable for further development by
Wednesday. An Air Force Reserve reconnaissance aircraft is scheduled
to investigate the disturbance Monday afternoon, if necessary.
Interests in Bermuda should monitor the progress of this system. The
next Special Tropical Weather Outlook will be issued by 8 PM EDT
this evening.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...40 percent.

$$
Forecaster Stewart

[Monsoonjr99]

I wanted to bring this post over here to re-emphasize a point about BI and BE systems like this one.

And that's this: Shear really isn't "kicking its butt".

What's causing all that shear is actually what will cause the lowering of pressures. It's 50 knots of highly divergent shear on the eastern flank of the large mid-upper level gyre that will be consolidating over the Bahamas. Make no mistake...if you don't have that 50 knot jet streak out there in mid-May, then that low is not going to form without the baroclinic enhancement that it's providing.

In short, with BI/BE systems, we need to look beyond the traditional "low-shear environment" paradigm that we normally want to see purely tropical development. Another way of saying this is: Don't discuss systems such as these with the mindset that they are "tropical" disturbances, because they're not. Think of them, in part or whole, as baroclinic, or non-tropical entities. This will keep you from getting "tropical myopia", as I like to call it.

--snip--

Does this mean there probably is not much chance of this becoming fully tropical, especially given the short time window? I don't expect this being anything more than subtropical.

[Hypercane_Kyle]

Has a legit chance to develop into a subtropical depression tomorrow evening before shear rips it apart.

[cycloneye]

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
730 PM EDT Sun May 19 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

An area of low pressure is expected to form several hundred miles
southwest of Bermuda by Monday. This system could develop into a
short-lived subtropical or tropical cyclone late tomorrow or
Tuesday while moving northward or northeastward. By Wednesday,
however, conditions are forecast to become unfavorable for further
development, and the system should become rapidly absorbed by a
cold front. An Air Force Reserve reconnaissance aircraft is
scheduled to investigate the disturbance Monday afternoon, if
necessary. Interests in Bermuda should monitor the progress of this
system. The next Special Tropical Weather Outlook will be issued by
Monday 2 AM EDT.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...50 percent.

$$
Forecaster Avila

[Tailspin]

https://imgur.com/DidMZGR

Interesting one to follow this, ohc don't really look supportive atm as-per cimss plot.

[StruThiO]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Mon May 20 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Satellite-derived wind data indicate that a trough of low pressure
has developed within a large area of cloudiness and disorganized
showers several hundred miles to the southwest of Bermuda. A low
pressure system is expected to form within this area of disturbed
weather later today, and possibly develop into a short-lived
subtropical or tropical cyclone by tonight or Tuesday while moving
northward or northeastward. By Wednesday, however, conditions are
forecast to become unfavorable for further development, and the
system should become rapidly absorbed by a cold front. An Air Force
Reserve reconnaissance aircraft is scheduled to investigate the
disturbance this afternoon, if necessary. Interests in Bermuda
should monitor the progress of this system. The next Special
Tropical Weather Outlook will be issued by 8 AM EDT today.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.

[Sciencerocks]

[Sciencerocks]

[plasticup]

https://imagizer.imageshack.com/img923/2700/4oRnNc.gif

That is the least threatening cloud I've seen in a while.

[USTropics]

Some slow development over night, still very broad circulation:

[SEASON_CANCELED]

Some slow development over night, still very broad circulation:

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/GIFS/GOES16-EUS-GEOCOLOR-1000x1000.gif

Looks healthier

[Gums]

Salute from slightly west of Michael !!

Not all that early for a storm considering a mild winter here in the southeast. We should get better word this afternoon'

From a climatology viewpoint, we generally have a mild Gulf and Carib storm season with a healthy El Nino. Current El Nino not all that strong, but definitely not neutral or La Nina. Seems the shear is stronger with a El Nino, so we Gulf Coast folks like to see that even if it affects rainfall for the farmers without irrigation wells.

What are the "rules" for naming this thing? If it gets above 45 mph we call it Andrea? Seems we have had a few named disturbances last coupla years just to keep folks interested besides we cycloniacs.

Gums sends...

[chaser1]

Some slow development over night, still very broad circulation:

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/GIFS/GOES16-EUS-GEOCOLOR-1000x1000.gif

Looks healthier

Quite so! Admittedly more then I would've expected at this juncture. Still can't see them finding a closed LLC with co-located convection and sustained near center 35kt winds by tomm. morning though. However I'd guess recon should have little difficulty finding higher gradient induced wind gusts well North and Northeast of Center. Looks like a health gale.

[MGC]

Looking more organized today. Good chance of a STD or STS later tonight or tomorrow.....MGC

[NDG]

This looks to be main area of broad low pressure, over an area of better UL divergence, becoming better defined and has that subtropical look to it.

[Kazmit]

Looks like it has a spin to it. Watching it closely here in Bermuda but it shouldn't be too much of a problem.

[wxman57]

This looks to be main area of broad low pressure, over an area of better UL divergence, becoming better defined and has that subtropical look to it.

https://i.imgur.com/q8VcK9Q.gif

Looks like a dissipating eddy in that loop. Good chance that if the NHC wants to upgrade it then it will be TD One this afternoon or this evening. I don't think it qualifies yet. Isn't recon heading out there soon?