Possible STD/S over N ATL 21–23 May (INVEST 90L is up)

[Shell Mound]

Both the GFS and the ECMWF are now hinting at short-lived subtropical development in the same region and timeframe, so I decided to post this thread.

[Iceresistance]

12z GFS trying to spin something off near Spain between May 24th & May 28th . . .

[tolakram]

Unless a feature actually exists we do not allow new threads on model storms. Please keep this in global model run thread.

[Nancy Smar]

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Wed May 19 2021

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

1. A non-tropical low pressure system is forecast to develop a few
miles northeast of Bermuda by late Thursday or early Friday. The low
is then expected to move southwestward over warmer water on Friday
and possibly acquire subtropical characteristics before the system
lifts out toward the north and northeast on Saturday and Sunday.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

Forecaster Stewart

[Shell Mound]

Both the GFS and the ECMWF are showing Subtropical Storm Ana (~45–55 kt / ~1005 mb) forming within the next two days and curving OTS south of Newfoundland.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Wed May 19 2021

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

1. A non-tropical low pressure system is forecast to develop a few
hundred miles northeast of Bermuda by late Thursday and produce
gale-force winds. The low could then move southwestward over warmer
waters on Friday and acquire some subtropical characteristics
before the system moves toward the north and northeast into a more
hostile environment by Sunday.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

High Seas Forecasts issued by the National Weather Service
can be found under AWIPS header NFDHSFAT1, WMO header FZNT01
KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php

Forecaster Blake

[InfernoFlameCat]

Very interesting its always those subtropical storms.

[AnnularCane]

Awwww...our first little yellow circle.

[tolakram]

Topics merged.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Wed May 19 2021

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

A non-tropical low pressure system is forecast to develop a few
hundred miles northeast of Bermuda by tomorrow afternoon and
produce gale-force winds. The low is then forecast to move
west-southwestward over warmer waters on Friday and could become a
short-lived subtropical cyclone over the weekend to the northeast
of Bermuda. The system is expected to move toward the north and
northeast into a more hostile environment by Monday. For more
information on this system, please see High Seas forecasts issued
by the Ocean Prediction Center.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...40 percent.

&&
High Seas Forecasts for this system can be found under AWIPS header
NFDHSFAT1, WMO header FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSFAT1.php

$$
Forecaster Blake

[Iceresistance]

Now we have a Medium for Bermuda . . .

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Wed May 19 2021

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

A non-tropical low pressure system is forecast to develop a few
hundred miles northeast of Bermuda by tomorrow afternoon and
produce gale-force winds. The low is then forecast to move
west-southwestward over warmer waters on Friday and could become a
short-lived subtropical cyclone over the weekend to the northeast
of Bermuda. The system is expected to move toward the north and
northeast into a more hostile environment by Monday. For more
information on this system, please see High Seas forecasts issued
by the Ocean Prediction Center.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...40 percent.

&&
High Seas Forecasts for this system can be found under AWIPS header
NFDHSFAT1, WMO header FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSFAT1.php

$$
Forecaster Blake

Also this:

[Sciencerocks]

[wxman57]

I think it's about 100% certain that a low center with 35-50 kt winds will develop NE of Bermuda by the weekend. The main uncertainty is whether the NHC will deem it name-worthy. The way they're talking, chances may be better than not that this is named Ana.

[aspen]

The 12z GFS, Euro, CMC, and ICON all have this becoming either TD One or TS/STS Ana. The GFS has a compact TC peaking at 997 mbar by 108 hours, before it gets squished in a front.

[ElectricStorm]

The 12z GFS, Euro, CMC, and ICON all have this becoming either TD One or TS/STS Ana. The GFS has a compact TC peaking at 997 mbar by 108 hours, before it gets squished in a front.

Of course this will develop just a few days after I put "no" on the May development thread lol

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed May 19 2021

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

1. A large area of cloudiness and thunderstorms has developed several
hundred miles east of Bermuda. A non-tropical low pressure system is
expected to form within this broad cloud system a few hundred miles
northeast of Bermuda by tomorrow and produce gale-force winds. The
low is then forecast to move westward and southwestward over warmer
waters on Friday, and will likely become a short-lived subtropical
cyclone late Friday and into the weekend near and to the northeast
of Bermuda. The system is expected to move toward the north and
northeast into a more hostile environment by late Sunday into
Monday. For more information on this developing system, please
see High Seas forecasts issued by the Ocean Prediction Center.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...60 percent.

High Seas Forecasts for this system can be found under AWIPS header
NFDHSFAT1, WMO header FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSFAT1.php

Forecaster Stewart

[DorkyMcDorkface]

The 12z GFS, Euro, CMC, and ICON all have this becoming either TD One or TS/STS Ana. The GFS has a compact TC peaking at 997 mbar by 108 hours, before it gets squished in a front.

Of course this will develop just a few days after I put "no" on the May development thread lol

I did the same...probably not alone in saying it caught me off-guard

[aspen]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed May 19 2021

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

1. A large area of cloudiness and thunderstorms has developed several
hundred miles east of Bermuda. A non-tropical low pressure system is
expected to form within this broad cloud system a few hundred miles
northeast of Bermuda by tomorrow and produce gale-force winds. The
low is then forecast to move westward and southwestward over warmer
waters on Friday, and will likely become a short-lived subtropical
cyclone late Friday and into the weekend near and to the northeast
of Bermuda. The system is expected to move toward the north and
northeast into a more hostile environment by late Sunday into
Monday. For more information on this developing system, please
see High Seas forecasts issued by the Ocean Prediction Center.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...60 percent.

High Seas Forecasts for this system can be found under AWIPS header
NFDHSFAT1, WMO header FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSFAT1.php

Forecaster Stewart

Wow, Stewart is straight up expecting development at this point. We’ll probably have a cherry on the map tomorrow.

[AnnularCane]

The 12z GFS, Euro, CMC, and ICON all have this becoming either TD One or TS/STS Ana. The GFS has a compact TC peaking at 997 mbar by 108 hours, before it gets squished in a front.

Of course this will develop just a few days after I put "no" on the May development thread lol

I did the same...probably not alone in saying it caught me off-guard

I haven't been "feeling" any May development this year. It's possible my feelings are less than reliable.

[Sciencerocks]