老農民版夜神月

  熱帶風暴  
編號：01 L
名稱：Ana

  基本資料  
擾動編號日期：2021 年 05 月 20 日 10 時
命名日期　　：2021 年 05 月 22 日 15 時
撤編日期　　：2021 年 05 月 25 日 08 時
登陸地點　　：無

  巔峰時期資料  
近中心最強風速 ：40  kt ( TS )
海平面最低氣壓 ：1006 百帕

  擾動編號資料  
90L.INVEST.30kts.1013mb.30.4N.55.4W


  NHC：30%  

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.

以上資料來自：NHC、颱風論壇整理製作

dom

NHC撤銷評級

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Mon May 24 2021

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

The National Hurricane Center has issued the last advisory on
Post-Tropical Cyclone Ana, located several hundred miles northeast
of Bermuda.

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Cangialosi
NNNN

dom

NHC03Z判定成為後熱帶氣旋

660
WTNT41 KNHC 240242
TCDAT1

Post-Tropical Cyclone Ana Discussion Number   8
NWS National Hurricane Center Miami FL       AL012021
1100 PM AST Sun May 23 2021

Ana has mainly remained devoid of deep and organized convection
today, with only a couple of short-lived bursts noted in satellite
imagery earlier this morning. The cyclone has been an exposed cloud
swirl through the afternoon and evening hours, and Ana continues
moving into a hostile environment characterized by cool sea-surface
temperatures, dry mid-level air, and increasing vertical wind shear.
Thus, Ana has become a post-tropical cyclone, and this will be the
final NHC advisory on the system.

Although a recent ASCAT-B pass missed the center of post-tropical
Ana, it still shows an area of 30-35 kt winds in the southeast
quadrant of the low near the edge of the swath. Therefore, the
initial intensity is set at 35 kt, with the slightly stronger winds
likely just a product of the accelerating forward speed of the
system. The post-tropical cyclone is embedded in deep-layer
southwesterly flow and will continue to accelerate northeastward
until it opens up into a trough and becomes absorbed by a strong
baroclinic zone approaching from the northwest on Monday.

Additional information on post-tropical Ana can be found in High
Seas Forecasts issued by the National Weather Service, under AWIPS
header NFDHSFAT1, WMO header FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSFAT1.php


FORECAST POSITIONS AND MAX WINDS

INIT  24/0300Z 38.3N  55.2W   35 KT  40 MPH...POST-TROPICAL
12H  24/1200Z 41.0N  50.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
24H  25/0000Z...DISSIPATED

$$
Forecaster Reinhart/Brown

老農民版夜神月

NHC21Z降TD

508
WTNT41 KNHC 232043
TCDAT1

Tropical Depression Ana Discussion Number   7
NWS National Hurricane Center Miami FL       AL012021
500 PM AST Sun May 23 2021

Other than brief puff of convection late this morning, tiny Ana has
been devoid of organized deep convection for several hours. ASCAT
overpass data from this morning indicated that the peak winds had
deceased to 35 kt. Due to the lack of convection since that time,
it is reasonable to assume that the vortex has spun down a bit, and
therefore the initial advisory intensity has been lowered to 30 kt.

Ana is over cool waters and surrounded by very dry air in the
mid-troposphere. The brief convection that did occur today was
quickly stripped away, indicating that the anticipated increase in
shear has begun. Satellite imagery suggests that the circulation of
Ana is approaching a strong subtropical upper-level jet just to its
east, which is expected to produce even stronger shear over the
cyclone. These conditions should prevent further convection, if any,
from surviving, and the cyclone is expected to degenerate into a
remnant low by tonight. What is left of Ana's low-level circulation
should open into a trough on Monday as it is absorbed by a large
baroclinic zone approaching from the northwest.

The depression continues to accelerate northeastward, and the
forward motion is now northeastward at 15 kt. An accelerating
northwestward motion is anticipated until dissipation as Ana
gets caught up in increasing deep-layer southwesterly flow.


FORECAST POSITIONS AND MAX WINDS

INIT  23/2100Z 37.5N  57.7W   30 KT  35 MPH
12H  24/0600Z 39.4N  53.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
24H  24/1800Z...DISSIPATED

$$
Forecaster Latto

老農民版夜神月

TS,Ana首報

WTNT41 KNHC 230830
TCDAT1

Tropical Storm Ana Discussion Number   5
NWS National Hurricane Center Miami FL       AL012021
500 AM AST Sun May 23 2021

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. The initial intensity remains 40 kt for this
advisory based on the earlier ASCAT data, which indicated that the
tropical-storm-force winds were confined to the south side of the
circulation.

Ana is not expected to be around much longer.  The storm is headed
for an environment of lower SSTs, drier air, and increasing wind
shear.  All of these factors should cause the compact cyclone to
lose strength and ultimately open into a trough in 24 to 36 hours.  
In fact, some of the models suggest that the storm could dissipate
even sooner than that.  The remnants of Ana will likely be absorbed
by a cold front on Monday.

The storm continues to increase its forward speed, and the initial
motion is now estimated to be 045/10 kt. A faster motion to the
northeast is expected until the cyclone dissipates.


FORECAST POSITIONS AND MAX WINDS

INIT  23/0900Z 35.7N  60.5W   40 KT  45 MPH
12H  23/1800Z 36.7N  58.7W   40 KT  45 MPH
24H  24/0600Z 39.4N  53.9W   35 KT  40 MPH
36H  24/1800Z...DISSIPATED

$$
Forecaster Cangialosi

老農民版夜神月

NHC判定已於06Z再轉化為TS

AL, 01, 2021052306,   , BEST,   0, 354N,  611W,  40, 1006, TS,  

老農民版夜神月

NHC首報預測目前便是巔峰

000
WTNT41 KNHC 220832
TCDAT1

Subtropical Storm Ana Discussion Number   1
NWS National Hurricane Center Miami FL       AL012021
500 AM AST Sat May 22 2021

Satellite images indicate that the low pressure system that is
located a couple of hundred miles northeast of Bermuda has become
better organized overnight.  The low now has a well-defined center
of circulation, some central deep convection, and thunderstorms that
are organized in curved bands to the north and northeast of the
center.   The system is considered a subtropical cyclone rather than
a tropical cyclone since it is still entangled with an upper-level
low as evident in water vapor satellite images, but it does have
some tropical characteristics as well.  The initial intensity is
estimated to be 40 kt, which makes the system Subtropical Storm Ana.

Ana is moving slowly to the west-southwest with the initial motion
estimated to be 240/3 kt.  An even slower motion is expected later
this morning, and Ana is forecast to meander through tonight while
it remains embedded within the upper-level low in weak steering
currents.  However, a mid- to upper-level trough moving off of
Atlantic Canada should cause Ana to turn northeastward thereafter
and accelerate in that direction on Sunday and Monday.  The NHC
track forecast lies close to the HCCA and TVCA consensus models.

Ana will likely change little in strength in the short term, but a
combination of increasing shear, dry air, and decreasing SSTs should
cause the storm to gradually weaken tonight and Sunday.  Nearly all
of the models show Ana opening up into a trough of low pressure in
about 48 to 60 hours, and so does the NHC forecast.  The remnant
trough will likely be absorbed by a front shortly thereafter.

The Bermuda Weather Service has a Tropical Storm Watch in effect
for the island of Bermuda.


FORECAST POSITIONS AND MAX WINDS

INIT  22/0900Z 34.2N  62.2W   40 KT  45 MPH
12H  22/1800Z 34.3N  62.6W   40 KT  45 MPH
24H  23/0600Z 35.1N  61.9W   35 KT  40 MPH
36H  23/1800Z 36.2N  59.6W   35 KT  40 MPH
48H  24/0600Z 37.9N  55.4W   35 KT  40 MPH
60H  24/1800Z...DISSIPATED

$$
Forecaster Cangialosi

老農民版夜神月

NHC命名Ana

01L ANA 210522 0600 34.2N 62.1W ATL 40 1006