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Hurricane Center - Atlantic


Tropical Outlook

altantic tropical storm outlook
Atlantic Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sunday September 23 2018

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

The National Hurricane Center is issuing advisories on weakening
Tropical Depression Eleven, located several hundred miles east of
the Windward Islands, and on Tropical Storm Kirk, located several
hundred miles south-southwest of the Cabo Verde Islands.

A broad area of low pressure located between Bermuda and the Bahamas
continues to produce limited shower and thunderstorm activity.
The strong upper-level winds currently affecting the system are
expected to diminish, and this could favor some development during
the next couple of days. The low is forecast to move westward and
west-northwestward at about 10 mph over the southwestern Atlantic
Ocean and by Tuesday or Wednesday, upper-level winds are forecast
to strengthen again, likely limiting the development.  By then,
the system is expected to be moving by the southeastern coast of
the United States.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...30 percent.

The evolution of a complex weather system over the central Atlantic
Ocean could lead to two separate episodes of subtropical or
tropical development during the upcoming week.  First, a non-
tropical low pressure system currently located about 1000 miles
west-southwest of the Azores is producing gale-force winds with
some associated showers and thunderstorms.  Conditions appear
conducive for this system to acquire some subtropical or tropical
characteristics during the next day or so while meandering over the
central Atlantic Ocean, and the low could become a subtropical or
tropical cyclone before it is overtaken and absorbed by a cold front
late Tuesday or Wednesday.  Additional information on this system
can be found in High Seas Forecasts issued by the National Weather
Service.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...70 percent.

A second non-tropical low pressure system is expected to form
along the central Atlantic cold front by Wednesday several hundred
miles west of the Azores.  Conditions appear conducive for this
system to also acquire subtropical or tropical characteristics by
the latter part of this week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

and under AWIPS header MIATCPAT2. Forecast/Advisories on Kirk are
issued under WMO header WTNT22 KNHC and under AWIPS header
MIATCMAT2.

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

Forecaster: Lixion Avila, National Hurricane Center


For detailed analysis see the Atlantic Tropical Weather Discussion.

Sea Temperatures

sea temperatures

sea temperatures north atlantic

sea temperatures south atlantic

Tropical Discussion

Atlantic Tropical Weather Discussion
NWS National Hurricane Center Miami FL
807 AM EDT Sunday September 23 2018

Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N.

Based on 0600 UTC surface analysis and satellite imagery through 1115 UTC.

...Special Features...

Tropical Storm Kirk centered near 9.1N 28.0W at 23/0900 UTC or 400 nm SSW of the Southernmost Cabo Verde Islands moving W at 16 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Some strengthening is forecast during the next day or two. Weakening is likely during the middle to latter part of the week. Scattered moderate to strong convection is from 08N-12N between 25W-32W. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT2/WTNT32 KNHC for more details.

Tropical Depression Eleven centered near 14.5N 55.0W at 23/0900 UTC or 360 nm ENE of the Windward Islands moving NW at 5 kt. Estimated minimum central pressure is 1009 mb. Maximum sustained wind speed is 25 kt with gusts to 35 kt. A slow west-northwest to northwest motion is expected until the system dissipates in a day or so. Scattered moderate convection is noted from 12N-15N between 52W-55W. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC for more details.

Satellite imagery indicates that a non-tropical low pressure system currently located about 1000 miles west-southwest of the Azores is producing gale-force winds with some associated showers and thunderstorms. Conditions appear conducive for this system to acquire some subtropical or tropical characteristics during the next day or so while meandering over the central Atlantic Ocean, and the low could become a subtropical or tropical cyclone before it is overtaken and absorbed by a cold front late Tuesday or Wednesday. The system has a high chance of tropical cyclone formation within the next 48 hours. Please refer to the latest Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more information.

A cold front extends from a 1004 mb low pressure located N of the area near 34N46W to 31N40W to 24N50W to 27N60W. The most recent scatterometer data provide observations of minimal gale-force winds N of 30N within 60 nm E of front with seas 11-13 ft. These conditions are expected to decrease below gale shortly at 23/1200 UTC.

Tropical Waves / Developing Storms

A tropical wave has its axis along 46W from 03N-16N and is moving west at 10-15 kt. The wave corresponds nicely with a maximum in TPW imagery. Model analyses depict an associated 700 mb trough along 44W. Isolated moderate convection is located from 03N-14N between 40W-50W.

A Central American tropical wave has its axis along 89W from 08N- 20N, moving west around 10 kt. The 700 mb trough associated with this wave is well depicted in model guidance, and TPW imagery shows abundant moisture in its environment. Widely scattered moderate convection is south of 20N between 85W-92W.

Monsoon Trough And Intertropical Convergence Zone - ITCZ
(The ITCZ is also known by sailors as the doldrums)
The monsoon trough extends from the African coast near 13N17W to 10N20W. It continues west of T.S. Kirk near 06N30W to 05N34W. The ITCZ begins near 05N34W to 04N40W to 05N44W, then resumes near 05N48W to the South American coast near 04N51W. Aside from the convection associated with the tropical wave and cyclones across the area, widely scattered moderate convection is located S of 75 the monsoon from 04N-11N between 10W-18W.

Discussion: Gulf Of Mexico
An upper-level cyclonic circulation is centered near 25N87W. This feature is enhancing convection across the eastern Gulf waters mainly along 84W. To the west, a surface trough is analyzed along 91W from 24N-29N. Scattered showers are noted along the trough. A cold front is entering the northwest Gulf enhancing convection north of 25N and west of 95W. This front is likely to stall and dissipate today. Gentle to moderate E to SE winds and seas 3 ft or less will prevail across most of the Gulf of Mexico through the middle of next week. A surface trough will develop over the Yucatan peninsula each evening, shift W over the SW Gulf each night, then dissipate by morning. Moderate to fresh winds will accompany this trough.

Discussion: Caribbean Sea
A tropical wave is moving across Central America, and a portion of the wave's convection is over the W Caribbean. Please see the Tropical Waves section for more details.

The eastern Pacific monsoon trough combined with diffluence aloft continues to enhance convection over portions of Panama and the waters of the southwest Caribbean from the coasts of Panama and Costa Rica northward to 13N and eastward to 78W. Plenty of moisture will persist over the extreme southwest Caribbean, Panama and Costa Rica through the weekend. Elsewhere, fresh to strong winds prevail over the central Caribbean. These winds will diminish across most of the basin by tonight.

Discussion: Atlantic Ocean
Currently, there are two tropical cyclones and a tropical wave between the west coast of Africa and the Lesser Antilles. Please see the Special Features and Tropical Waves sections for more details.

A broad 1010 mb low is centered near 28N67W. A surface trough runs through the low from 30N64W to the low center to 26N72W. Scattered showers are noted along the trough and near the low. Unfavorable upper-level winds and dry air are expected to limit development today, but conditions could become more conducive for some development of this system on Monday or Tuesday while it moves westward and west-northwestward over the southwestern Atlantic Ocean. By the middle of next week, strong upper-level winds are likely to limit additional development as the system turns northward and moves closer to the southeastern coast of the United States. This feature has a low chance of tropical cyclone formation during the next 48 hours.

The remainder of the basin is under the influence of a surface ridge, anchored by a 1028 mb high centered near 40N21W.

Forecaster: Mike Formosa, National Hurricane Center



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