Tropical Storm Ana

[WxWatcher007]

Ok, it's time to get back into the swing of things. 

This is our first cherry of the season and will likely become a named storm, extending the streak of named preseason storms to 7 years. Not expected to have any US impacts. 

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Fri May 21 2021

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

1. Showers and thunderstorms associated with a non-tropical low 
pressure area centered about 450 miles east-northeast of Bermuda 
have become better organized during the past several hours.  The 
low has not yet acquired subtropical storm characteristics.  
However, if current trends continue advisories could be initiated 
on the system later today or tonight as it moves westward 
to west-southwestward to the northeast of Bermuda.  Subsequently, 
the low is forecast to move northeastward into a more hostile 
environment by Saturday night or Sunday.  Additional information on 
this low pressure area can be found in High Seas forecasts issued by 
the NOAA Ocean Prediction Center and forecast products, including a 
tropical storm watch, issued by the Bermuda Weather Service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.

[Cat Lady]

Does anyone have any knowledge on how long we've been naming sub tropical systems? I assume it correlates with the satellite era, but I'm wondering if there are any other specifics.

[WxWatcher007]

17 minutes ago, Cat Lady said:

Does anyone have any knowledge on how long we've been naming sub tropical systems? I assume it correlates with the satellite era, but I'm wondering if there are any other specifics.

The NHC started naming subtropical storms in 2002 but they had a separate designation (numbers, rather than a name) for decades. More info here: https://www.weather.gov/source/zhu/ZHU_Training_Page/tropical_stuff/sub_extra_tropical/subtropical.htm

[NorthHillsWx]

1 hour ago, WxWatcher007 said:

The NHC started naming subtropical storms in 2002 but they had a separate designation (numbers, rather than a name) for decades. More info here: https://www.weather.gov/source/zhu/ZHU_Training_Page/tropical_stuff/sub_extra_tropical/subtropical.htm

Imo it should have stayed that way, though from an impact perspective I understand why to group them together with tropical systems as they share the same impacts. 

[Tezeta]

10 minutes ago, NorthHillsWx said:

Imo it should have stayed that way, though from an impact perspective I understand why to group them together with tropical systems as they share the same impacts. 

Let’s only name bonafide 65kt hurricanes. Avoids the dipping into the secondary list problem. Kill off all weaksauce StS and regular TS. Last season had plenty that barely made the cut. 

[WxWatcher007]

Very close to advisories per the 2pm outlook. Still at 90% odds.

[thunderman]

Still 90% with 8PM outlook

Quote

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Fri May 21 2021

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

1. Recent satellite images indicate that the area of low pressure 
located about 250 miles northeast of Bermuda is well-defined and is
gradually acquiring subtropical characteristics. In addition, 
earlier satellite-derived wind data revealed that the system is
producing gale-force winds. The associated shower and thunderstorm
activity has increased slightly over the past several hours. If that 
trend continues, it would result in advisories being initiated on
the system later tonight or Saturday morning while it moves slowly
westward to west-southwestward to the northeast of Bermuda.  The  
low is forecast to move northeastward into a more hostile 
environment by Saturday night or Sunday and the system’s development 
chances diminish after that time. Additional information on this 
low pressure area can be found in High Seas forecasts issued by the 
NOAA Ocean Prediction Center and forecast products, including a 
tropical storm watch, issued by the Bermuda Weather Service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.

 

[WxWatcher007]

Subtropical Storm Ana Discussion Number   2
NWS National Hurricane Center Miami FL       AL012021
1100 AM AST Sat May 22 2021
 
Satellite imagery and radar data from Bermuda indicate that the
central convection associated with Ana has changed little in
organization during the past several hours, with a complex of small
bands near the center at this time.  The initial intensity will be
held at 40 kt based on the latest intensity estimate from TAFB, 
although recently-received ASCAT data suggests this could be a 
little generous.  Although the cyclone has some characteristics of 
a tropical cyclone, Ana remains a subtropical storm based on its 
position near the center of a large upper-level low pressure system 
and the current lack of anticyclonic upper-level outflow.
 
The initial motion is 270/3.  Ana and the large low it is embedded
in are expected to turn northward later today as a developing
mid-latitude cyclone over eastern Canada and the New England
states erodes the subtropical ridge west of Ana.  After that, the
storm is expected to turn northeastward on the southeast side of
the mid-latitude cyclone.  The track guidance is in good agreement
with this scenario, and the new track forecast is similar to, but a
little slower than, the various consensus models.
 
Little change in strength is expected for the next 12 h or so.
After Ana recurves, a combination of increasing shear, dry air, and
decreasing SSTs should cause the storm to gradually weaken tonight
and Sunday.  The large-scale models agree upon Ana opening up into
a trough of low pressure in 36-48 h, and the official forecast
shows this happening just after 48 h.  The remnant trough will
likely be absorbed by a cold front associated with the mid-latitude
cyclone shortly thereafter.
 
The Bermuda Weather Service has discontinued the Tropical Storm
Watch for Bermuda.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/1500Z 34.3N  63.0W   40 KT  45 MPH
 12H  23/0000Z 34.8N  62.8W   40 KT  45 MPH
 24H  23/1200Z 35.8N  61.2W   35 KT  40 MPH
 36H  24/0000Z 37.2N  57.9W   35 KT  40 MPH
 48H  24/1200Z 39.7N  52.9W   35 KT  40 MPH
 60H  25/0000Z...DISSIPATED
 
$$
Forecaster Beven

[Prospero]

Ana begins 2021, what name where it end? What name will be the one to remember?

Is "Ida" a safe bet as the name to never forget?

 

 

[Windspeed]

Ana did transition to a purely tropical system, even if it will be short-lived.

Satellite images indicate that Ana has contracted significantly since yesterday and now has a compact area of moderate convection around the center. Given the tight low-level circulation, small radius of maximum wind, and compact central convection, Ana is now estimated to have transitioned from a subtropical storm to a tropical storm.

[Tezeta]

5 hours ago, Windspeed said:

Ana did transition to a purely tropical system, even if it will be short-lived.
 

What a hottie

 

[WxWatcher007]

Tropical Storm Ana Discussion Number   6
NWS National Hurricane Center Miami FL       AL012021
1100 AM AST Sun May 23 2021

Ana is barely holding on as a tropical cyclone this morning, as the
core of the system has become devoid of organized deep convection. A
recent ASCAT overpass showed that wind field is slowly weakening,
with peak winds of 35 kt located just to the southeast of the
center. Based on this data, the initial advisory intensity has also
been decreased to 35 kt.

The cyclone is currently located over cool SSTs of about 20 degrees
C and surrounded by very dry air in the mid-troposphere. The
environmental conditions will only become more hostile through
tonight, as Ana gets caught between a digging mid- to upper-level
trough to its northwest and a strong subtropical upper-level jet to
its southeast. These features will impart increasing southwesterly
shear over the system by later today, and any convection that tries
to regenerate should be stripped away. Whatever is left of Ana's
low-level circulation should then open into a trough on Monday as it
becomes absorbed by a large approaching baroclinic zone
associated with the upper-trough.

The storm is now moving northeastward at 12 kt, and an accelerating
forward speed is anticipated until dissipation as Ana gets caught up
in increasing deep-layered southwesterly flow.


FORECAST POSITIONS AND MAX WINDS

INIT  23/1500Z 36.6N  59.4W   35 KT  40 MPH
 12H  24/0000Z 38.0N  56.7W   35 KT  40 MPH
 24H  24/1200Z 41.7N  50.3W   35 KT  40 MPH...POST-TROPICAL
 36H  25/0000Z...DISSIPATED

$$
Forecaster Latto