Non Tropical Atlantic Low

[tolakram]

I think this is spinning down but I've been watching it for a few days and there continues to be light convection near the center.



Every low is a bit different.

[HURAKAN]

Yesterday I noticed this system but didn't post anything since it's too far north for anything tropical or subtropical to occur. Still, interesting to watch.

[HURAKAN]

All the images:















GFS 24 hrs:


GFS 48 hrs:


GFS 72 hrs:


GFS 96 hrs:


Windshear:


Windshear tendency:

[Frank2]

I couldn't help but notice the strong shear across the Caribbean - looks like the May 5 first (statistical) maximum might pass quietly...

[tolakram]

So what's powering this sucker anyway. Convection near the center has been persistent all day.


http://www.ssd.noaa.gov/goes/east/natl/loop-rb.html

[HURAKAN]

Satellite loops indicate the system is still non-tropical in nature as the low-level circulation looks to be attached to a cold front or trough. Very interesting storm but there shouldn't be any transition to subtropical and/or tropical in the future.

[tolakram]

Sure, it's too far north and the water is way too cold to boot, but I'm still curious why it's behaving this way. I suppose it can be chalked up to extratropical lows not always following the rule book.


SST

[tolakram]

http://www.ssd.noaa.gov/goes/east/natl/loop-wv.html



The water vapor loop is interesting to look at. You can see the two air masses but it seems to me the center of low pressure is being surrounded by moist air. /shrug If any met wants to school me on what I'm seeing it would be most appreciated.

[HURAKAN]

TWD 805 PM:

A
DEEP LAYERED TROUGH IS OVER THE REMAINDER OF THE CENTRAL ATLC
WITH THE UPPER LOW CENTERED N OF THE REGION NEAR 35N47W AND A
1000 MB SURFACE LOW NEAR 35N48W. A SURFACE TROUGH EXTENDS INTO
THE REGION THROUGH 32N39W S ALONG 28N41W THEN SW TO 20N54W WITH
ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH.
BROAD UPPER RIDGE COVERS THE E ATLC WITH THE AXIS ALONG 24W
EXTENDING TO 31N WITH A DEEP LAYERED LOW/TROUGH INLAND OVER W
AFRICA. A WEAK SURFACE TROUGH IS BENEATH THE UPPER RIDGE
EXTENDING FROM 25N25W TO 31N29W.

[Matt-hurricanewatcher]

It looks kind of subtropical. But appearances can be a challege to put a finger on if it has a warm core. I would say its not impossible that it could develop into a borderline subtropical like system.

[tolakram]

It's over 64-65F water ... I don't think it can be anything but non-tropical but I would like to know why it's behaving the way it is. All the extratropical lows I remember watching never have convection of any significance near the center of the low. I'm guessing it's an area where the warm/cold or moist/dry air is mixing and creating an area ripe for convection.

[MiamiensisWx]

The "water's too cold" argument has been proven false on several occasions. Many tropical and subtropical systems (see Epsilon, Zeta, Ana, et al) have formed over 64-65 F SSTs and even cooler waters. Other factors such as the placement of the upper low above the system, shear, and heat content are far more decisive as to whether the transition and development takes place.

With that said, this one (gale center) likely will not complete the transition to a warm core system at the low levels.

[george_r_1961]

Just glancing at the sattelite imagery it looks like a cold core low that is occluding or closing off and separating from the parent front. It will likely spin down over the next day or so.

If this were late summer or fall I would be concerned that this could become a tropical or subtropical cyclone but like others that have posted in this thread I feel that any tropical development is unlikely.

[Ptarmigan]

The "water's too cold" argument has been proven false on several occasions. Many tropical and subtropical systems (see Epsilon, Zeta, Ana, et al) have formed over 64-65 F SSTs and even cooler waters. Other factors such as the placement of the upper low above the system, shear, and heat content are far more decisive as to whether the transition and development takes place.

With that said, this one (gale center) likely will not complete the transition to a warm core system at the low levels.

I saw a chart that higher and colder cloud tops is a factor as well.

[Category 5]

The title of the thread says it all.

It's a frontal low over 17C waters.

[Category 5]

The "water's too cold" argument has been proven false on several occasions. Many tropical and subtropical systems (see Epsilon, Zeta, Ana, et al) have formed over 64-65 F SSTs and even cooler waters. Other factors such as the placement of the upper low above the system, shear, and heat content are far more decisive as to whether the transition and development takes place.

With that said, this one (gale center) likely will not complete the transition to a warm core system at the low levels.

Actually I believe Ana, Epsilon, and Zeta formed over about 22C SST's.

[HURAKAN]

[Cyclone1]

Cat5: Yeah, I don't think a storm has ever formed over anything colder than 70.