Hurricane City Hurricane TV CaneTalk Logo
CaneTalk Forum | Search Messages | Post a New Message | Member Map

| HurricaneCity | Tropical Atlantic | Chat Room | Board Rules




11am Sat: 96L becomes Potential Tropical Cyclone Fifteen; TS watches for parts of Lesser Antilles

Posted by Chris in Tampa on 9/16/2017, 11:34 am

Track:
http://www.nhc.noaa.gov/refresh/graphics_at5+shtml/?cone#contents

Floater:
http://www.ssd.noaa.gov/PS/TROP/floaters/15L/15L_floater.html
Wider Atlantic views: http://www.ssd.noaa.gov/PS/TROP/trop-atl.html





Potential Tropical Cyclone Fifteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL152017
1100 AM AST Sat Sep 16 2017

Satellite images indicate that the area of low pressure located
several hundred miles east of the Lesser Antilles has become better
organized with curved banding features now better established.
Since there is still no indication of a well-defined center and
because tropical storm watches have been issued for portions of
the Leeward Islands, NHC has initiated advisories on this system as
a potential tropical cyclone.  The initial wind speed is estimated
to be 30 kt based on a blend of the Dvorak classifications from TAFB
and SAB.

The initial motion estimate is 280/19, but this is uncertain due to
the lack of a clear center.  A slower west-northwestward motion is
expected during the next several days as a mid-level ridge to the
north of the system weakens but remains nearly stationary.  The NHC
track forecast takes the system across the Leeward Islands in a few
days and then near the Virgin Islands and Puerto Rico by the end of
the forecast period.  It should be noted that confidence in the
track and forward speed of this system is low due to the spread in
the models and the current lack of a well-defined center.

The disturbance is expected to be in environmental conditions
conducive for strengthening during the next several days as the
shear is expected to be 10 kt or less while the cyclone moves over
warm 29 deg C SSTs.  These conditions should allow for at least
steady strengthening, and the models unanimously show that trend.
The NHC intensity forecast is conservative for now, but does show
the system becoming a tropical storm later today and a hurricane by
the time it reaches the Leeward Islands.

KEY MESSAGES:

1. The disturbance is expected to intensify and will likely bring
tropical storm and hurricane conditions as well as flooding
rainfall to portions of the Lesser Antilles early next week. These
conditions could also spread into the Virgin Islands and Puerto Rico
by mid week. Interests in these areas should monitor the progress
of this system and follow any advice given by local officials.

FORECAST POSITIONS AND MAX WINDS

INIT  16/1500Z 12.2N  50.5W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
12H  17/0000Z 12.8N  52.8W   35 KT  40 MPH...TROPICAL STORM
24H  17/1200Z 13.6N  55.1W   40 KT  45 MPH
36H  18/0000Z 14.3N  56.9W   50 KT  60 MPH
48H  18/1200Z 15.0N  58.6W   60 KT  70 MPH
72H  19/1200Z 16.3N  61.3W   75 KT  85 MPH
96H  20/1200Z 17.6N  64.0W   80 KT  90 MPH
120H  21/1200Z 18.7N  67.3W   80 KT  90 MPH

$$
Forecaster Cangialosi





Potential Tropical Cyclone Fifteen Advisory Number   1
NWS National Hurricane Center Miami FL       AL152017
1100 AM AST Sat Sep 16 2017

...TROPICAL STORM WATCHES ISSUED FOR A PORTION OF THE LESSER
ANTILLES...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...12.2N 50.5W
ABOUT 755 MI...1220 KM ESE OF THE LESSER ANTILLES
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The government of St. Lucia has issued a Tropical Storm Watch for
St. Lucia.

The government of France has issued a Tropical Storm Watch for
Martinique and Guadeloupe.

The government of Barbados has issued a Tropical Storm Watch for
Dominica.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* St. Lucia
* Martinique
* Guadeloupe
* Dominica

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

Interests elsewhere in the Lesser Antilles should monitor the
progress of this system.  Additional Tropical Storm or Hurricane
Watches will likely be issued later today.

For storm information specific to your area, please monitor products
issued by your national meteorological service.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 1100 AM AST (1500 UTC), the disturbance was centered near
latitude 12.2 North, longitude 50.5 West.  The system is moving
toward the west near 22 mph (35 km/h).  A slower west-northwest
motion is expected during the next couple of days.  On the forecast
track, the system is expected to approach the Leeward Islands on
Monday.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Strengthening is expected during the next 48 hours. The
disturbance is forecast to become a tropical storm later today and
could be near hurricane strength when it approaches the Leeward
Islands.

Satellite images indicate that the disturbance has become better
organized, and it is expected to become a tropical cyclone later
today or tonight.
* Formation chance through 48 hours...high...near 100 percent
* Formation chance through 5 days...high...near 100 percent

The estimated minimum central pressure is 1008 mb (29.77 inches).


HAZARDS AFFECTING LAND
----------------------
WIND:  Hurricane conditions are possible within portions of Leeward
Islands by Monday night or Tuesday, with tropical storm conditions
possible on Monday.

RAINFALL:  The system is expected to produce total rain
accumulations of 5 to 10 inches with isolated maximum amounts of 15
inches across portions of the central and southern Leeward Islands
through Tuesday night.  These rains could cause life-threatening
flash floods and mudslides.

SURF:  Swells generated by the system are expected to begin
affecting the Lesser Antilles by Sunday night.  These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.


NEXT ADVISORY
-------------
Next intermediate advisory at 200 PM AST.
Next complete advisory at 500 PM AST.

$$
Forecaster Cangialosi

136



In this thread:

11am Sat: 96L becomes Potential Tropical Cyclone Fifteen; TS watches for parts of Lesser Antilles - Chris in Tampa, 9/16/2017, 11:34 am

< Return to message board



Post A Reply

Subject:


Message:

Add Smiley:

Add Image (Tutorial):
Image URL:
Add  


Embed Video or other Social Media:
Page URL of YouTube Video: Add
Page URL of Facebook post or image (not image URL): Add
Page URL of Twitter tweet: Add
Page URL of recorded Ustream Video: Add
Page URL of Vine Video: Add
If you prefer to embed something manually for any of these sites, you can also do that. For Ustream, you can only embed live videos manually rather than using the above feature. No other sites are currently supported.

If you embed something manually please be aware that due to the security restrictions on some browsers manually entering embedded code may not allow it to appear correctly when you view it. However, after you post the message it will work properly. This will not be a problem if you use the above feature to add embedded content.