# St Barts Forums > Storm Tracker >  >  Current Five-Day Tropical Weather Outlook

## cassidain

Sorry, this is only the Atlantic Outlook  :cool: 

Three tropical waves currently out there, but none appear to be heading the direction of our belle île.

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## cec1

Fantastique!

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## GramChop

Yay for St Barth.  :Big Grin: 

Oh, dang for the Northeastern US.  :Embarrassment:

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## stbartshopper

Good news but still a long ways to go!

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## cassidain

> Good news but still a long ways to go!



current five day forecast:


still a long way to go thru hurricane season, no doubt.

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## stbartshopper

Potentially Ida, Julian and Kate-
An update- now an 80% probability at least one of the three will develop into a storm-
https://www.google.com/amp/s/www.orl...outputType=amp

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## cassidain

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Wed Aug 25 2021

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

1. A broad area of low pressure is expected to form over the 
southwestern Caribbean Sea during the next day or so from a tropical 
wave currently located over northwestern Colombia and the 
south-central Caribbean Sea.  Environmental conditions are forecast 
to be conducive for development, and a tropical depression is likely 
to form late this week or over the weekend while the system moves 
west-northwestward to northwestward over the northwestern Caribbean 
Sea. The disturbance is expected to move near or across the Yucatan 
Peninsula of Mexico on Saturday, and move into the western Gulf of 
Mexico by Sunday where conditions could be favorable for additional 
development to occur. 
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...80 percent.

2. A broad trough of low pressure is producing disorganized showers and 
thunderstorms over the central tropical Atlantic about 800 miles 
southeast of Bermuda. Only slow development of this system is 
expected during the next day or so due to unfavorable upper-level 
winds. Afterwards, environmental conditions are forecast to become 
more conducive for development, and a tropical depression is likely 
to form late this week or this weekend while the system turns 
eastward over the central Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...high...80 percent.

3. A tropical wave over the far eastern tropical Atlantic located 
several hundred miles southwest of the Cabo Verde Islands is 
producing a disorganized area of showers and thunderstorms. Some 
development of this system is possible over the next several days 
while it moves west-northwestward at 10 to 15 mph over the eastern 
tropical Atlantic. Upper-level winds are forecast to become less 
conducive for development by this weekend.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...30 percent.

Forecaster Stewart

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## stbartshopper

So it seems none of those three potential storms are concerns for SBH?

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## cassidain

Ida expected to visit Louisiana as a Cat 2 or 3 H, TS 10 is expected to head due North and weaken to a TD, Invest 1 is headed NorthEast, so Invest 2 is the only TW folks on SBH will be keeping an eye on over next days. Question is how North and how West it travels and how much it strengthens . . . or not. À suivre . . .

2. A tropical wave is expected to emerge off the coast of west Africa 
by the middle of next week.  Thereafter, environmental conditions 
appear somewhat conducive for gradual development toward the end of 
next week as the system moves west-northwestward to northwestward at 
10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...50 percent.

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## cassidain

Invest 1 off the coast of Africa may be one to keep a close eye on



ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Mon Aug 30 2021

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

The National Hurricane Center is issuing advisories on Tropical  
Storm Ida, located inland over western Mississippi, and on recently 
upgraded Tropical Storm Kate, located over the central tropical 
Atlantic.

1. Satellite-derived wind data and satellite imagery indicate that an 
area of low pressure has formed over the far eastern Tropical 
Atlantic in association with a tropical wave that recently moved off 
the west coast of Africa.  Environmental conditions are conducive 
for development, and a tropical depression is likely to form within 
the next couple of days while the system moves west-northwestward at 
10 to 15 mph over the eastern tropical Atlantic. 
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

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## cassidain

Looks like a hurricane coming. Hopefully steering out to sea. À suivre. . .

142 
WTNT42 KNHC 312035
TCDAT2

Tropical Depression Twelve Discussion Number   1
NWS National Hurricane Center Miami FL       AL122021
800 PM CVT Tue Aug 31 2021

Satellite imagery, along with earlier scatterometer data, indicates 
that the low pressure area over the eastern tropical Atlantic has 
a well-defined circulation and sufficient organized convection to 
be considered a tropical depression.  Thus, advisories are being 
initiated on Tropical Depression Twelve.  The initial intensity is 
set at 30 kt based on satellite intensity estimates from TAFB and 
SAB as well as the scatterometer data.

The initial motion is a somewhat uncertain 285/14.  A strong low- 
to mid-level ridge to the north should cause the cyclone to move 
westward at a faster forward speed for the next 36 h or so, 
followed by a gradual turn toward the west-northwest and northwest 
by the end of the period as the depression moves along the 
southwest side of the ridge.  There is some spread in the guidance 
after 36-48 h, with the GFS and GFS ensemble mean showing a more 
northward motion while the UKMET and the UKMET ensemble mean show a 
more westward motion.  The official forecast is near the middle of 
the guidance envelope and is close to the HFIP corrected consensus 
model, which is a little to the south of the other consensus models.

Conditions appear favorable for intensification during the next 72 
h or so as the cyclone is in a moist environment with light shear 
and warm sea surface temperatures.  The intensity forecast thus 
calls for the cyclone to become a tropical storm in 12 h or so and 
reach hurricane strength in 48-60 h.  By the end of the forecast 
period, the forecast track takes the cyclone over slightly cooler 
water and into a drier air mass.  Based on this, the intensity 
forecast calls for a slower development rate.  The official 
intensity forecast is in the middle of the intensity guidance, and 
it is possibly conservative given that many of the global models 
are showing the development of a large and powerful tropical 
cyclone.

FORECAST POSITIONS AND MAX WINDS

INIT  31/2100Z 11.2N  21.1W   30 KT  35 MPH
 12H  01/0600Z 11.6N  23.9W   35 KT  40 MPH
 24H  01/1800Z 12.0N  27.5W   40 KT  45 MPH
 36H  02/0600Z 12.1N  30.7W   50 KT  60 MPH
 48H  02/1800Z 12.5N  33.7W   60 KT  70 MPH
 60H  03/0600Z 13.3N  36.5W   70 KT  80 MPH
 72H  03/1800Z 14.3N  39.0W   80 KT  90 MPH
 96H  04/1800Z 16.5N  43.5W   85 KT 100 MPH
120H  05/1800Z 19.5N  47.5W   90 KT 105 MPH

$$
Forecaster Beven

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## cec1

Case . . . I appreciate the guidance & hope that you will spell out any risks for me in simple terms.  Like, “batten down the hatches” or “get the hell out of there!”  LOL!

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## cassidain

Mon ami, I’m sure you’re plugged into savvy island grapevine. But, I’ll try to do my bit

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## cassidain

the latest forecast. you dont want to encounter this storm.

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## JEK

You would think we are at the height of hurricane season <checking calendar> Oh, we are!

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## cassidain



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## cassidain

a TW to keep an eye on. conducive environmental conditions and westerly direction



2. A tropical wave continues to produce a concentrated area of showers 
and thunderstorms just southeast of the Cabo Verde Islands. 
Environmental conditions appear generally conducive for gradual 
development, and a tropical depression is likely to form late this 
weekend or early next week while the system moves westward over the 
far eastern Atlantic.  Regardless of development, this system is 
likely to bring gusty winds and locally heavy rain across the Cabo 
Verde Islands later today and tonight.  
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...70 percent.

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## cassidain



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## cassidain

1. Showers and thunderstorms associated with a low pressure area 
located a few hundred miles south of the Cabo Verde Islands continue 
to show signs of organization.  Environmental conditions are 
expected to remain conducive for development, and a tropical 
depression is likely to form during the next couple of days while 
the system moves generally westward at about 15 mph across the 
eastern tropical Atlantic Ocean.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.

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## cassidain

Rose and Peter headed out to sea, but Invest #1 off the coast of Africa is next one to keep an eye on . . .



ZCZC MIATWOAT ALLTTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Mon Sep 20 2021

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

The National Hurricane Center is issuing advisories on Tropical 
Storm Peter, located east-northeast of the northernmost Leeward 
Islands, and on Tropical Storm Rose, located over the eastern 
tropical Atlantic Ocean.

1. A tropical wave located over the far eastern tropical Atlantic 
several hundred miles south-southeast of the Cabo Verde Islands 
is producing an area of showers and thunderstorms that are showing 
some signs of organization.  Upper-level winds are expected to 
become more conducive for further development by midweek, and a 
tropical depression is likely to form by Friday while the system 
moves westward at 10 to 15 mph across the eastern and central 
tropical Atlantic Ocean.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...high...70 percent.

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## rolltide

The latter part of next week looks scary.

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## JEK

Yes indeed!

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## JEK

Hoo-Boy!

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## cassidain

000
WTNT43 KNHC 222054
TCDAT3

Tropical Depression Eighteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL182021
500 PM AST Wed Sep 22 2021

The tropical wave that NHC has been monitoring over the last several 
days has gradually become better organized. The satellite structure 
in particular is quite impressive for a tropical depression, with 
both the 1800 UTC subjective Dvorak estimates from TAFB and SAB 
at T2.5/35 kt. This bigger question, however, was if the system 
possessed a well-defined closed earth-relative circulation. An 
ASCAT-C pass from earlier this morning hinted that the circulation 
was becoming better defined, with the development of westerly 
low-level winds to the south of the convective shield. This westerly 
low-level flow is also confirmed by atmospheric motion vectors 
(AMVs) available from the GOES-16 meso domain over the system. While 
the low-level circulation may still be somewhat broad, it now 
appears to be well-defined enough to mark the formation of a 
tropical cyclone. The initial intensity is set at 30-kt, in 
agreement with peak wind retrievals of 28-30 kt by the earlier 
scatterometer data.  

The initial motion is estimated to be at 270/13 kt, though this is 
somewhat uncertain given that the center has only recently formed. 
An expansive mid-level ridge is located to the north and west of 
the cyclone, which should maintain its heading toward the west, 
though with a gradual gain in latitude as the system approaches 
the western extent of the ridge by day 5. The track guidance is in 
excellent agreement on this track evolution for the first three 
days, with just a bit more spread in the guidance thereafter. The 
ECMWF and its ensemble mean towards the end of the forecast is on 
the left side of the guidance envelope, while the GFS and HWRF 
models are currently on the right side. For the first NHC track 
forecast, I have elected to stay close to the track consensus aids, 
taking a blend of the HCCA and TCVN aids which are near the 
middle of the guidance envelope.

The environment ahead of the tropical depression appears quite 
favorable for intensification. Vertical wind shear is forecast by 
both the ECWMF- and GFS-based SHIPS guidance to stay at or under 10 
kt for the next 3-5 days as the storm traverses warm 28-29 C sea 
surface temperatures. Most of the guidance responds to this 
environment by indicating strengthening, and the NHC intensity 
guidance follows suit, showing a steady increase in intensity 
throughout the forecast period. While it might take a bit of time 
for the formative low-level circulation to become vertically aligned 
with the mid-level center, once that occurs, it is possible a period 
of rapid intensification could occur during the five day forecast. 
The forecast intensity by 120 hours (100 kt) is on the higher end of 
the guidance envelope, but not as high as the latest HWRF or HAFS-B 
forecasts. 

FORECAST POSITIONS AND MAX WINDS

INIT  22/2100Z 10.1N  33.9W   30 KT  35 MPH
 12H  23/0600Z 10.1N  36.0W   35 KT  40 MPH
 24H  23/1800Z 10.5N  38.6W   40 KT  45 MPH
 36H  24/0600Z 11.0N  41.1W   50 KT  60 MPH
 48H  24/1800Z 11.7N  43.4W   60 KT  70 MPH
 60H  25/0600Z 12.4N  45.3W   70 KT  80 MPH
 72H  25/1800Z 13.0N  46.8W   80 KT  90 MPH
 96H  26/1800Z 14.2N  49.5W   90 KT 105 MPH
120H  27/1800Z 16.0N  52.5W  100 KT 115 MPH

$$
Forecaster Papin

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## cassidain

this current graph appears to represent tracks of all the models. consensus seems to be solid cat 3 and a near miss for saint-barth. undoubtedly, our island friends are following this storm very closely.

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## amyb

I like the MISS part of this forecast, Cass

Keep safe and dry friends and family.

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## cassidain

The peak season parade continues, as Sam begins to weaken and move across open ocean, and two new tropical disturbances move westward from off the coast of Africa.



2. Disorganized showers and thunderstorms are associated with a broad 
area of low pressure located several hundred miles southwest of the 
Cabo Verde Islands.  Environmental conditions are forecast to be 
conducive for further development of this disturbance, and a 
tropical depression is likely to form around midweek while it moves 
westward to west-northwestward at 5 to 10 mph over the central 
tropical Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...high...80 percent.

3. A tropical wave is expected to move off of the west coast of Africa 
later today.  Upper-level winds are forecast to be conducive for 
gradual development thereafter, and a tropical depression is likely 
to form in a few days while the system moves westward to 
west-northwestward at 10 to 15 mph over the far eastern tropical 
Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...high...80 percent.

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## cassidain

For Oct 7 in storm season not bad.

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## cassidain

bon

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