Atlantic Tropical Weather Discussion (Text)

AXNT20 KNHC 211751

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1251 PM EST Tue Nov 21 2017

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. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through 
1645 UTC.

Low pressure is forecast to develop over the central Gulf of
Mexico on Wednesday, while high pressure builds SE from the
central US. The pressure gradient between these two features will
produce near gale to gale force northerly winds S of 21N W of 
95W. The gale force wind field is expected to persist until mid 
Thursday morning...diminishing into strong to near gale force 
strength by Thursday afternoon across portions of the SW Gulf of 
Mexico. See the latest NWS High Seas Forecast under AWIPS/WMO 
headers MIAHSFAT2/FZNT02 KNHC for more details.

A 1003 mb low centered near 32N25W is producing gale force winds
across the Meteo-France forecast area of Irving as confirmed by a
morning scatterometer pass indicating 35 kt winds from 29N to 33N
between 22W and 25W. These winds are forecast to diminish below 
gale force by 0000 UTC tonight. Please refer to the Meteo- France 
forecast found at www.meteofrance.com/previsions- meteo- 
marine/bulletin/grandlarge/metarea2 for more details. 

The monsoon trough extends from the African coast near 11N15W to 
09N20W. The Intertropical Convergence Zone axis extends from 
09N20W to 08N35W to 08N45W to the South America Coast near 
06N57W. Scattered moderate convection is from 02N to 13N between
10W and 31W, and from 03N to 07N between 31W and 44W.


An upper trough over the central Gulf of Mexico is supporting a
1013 mb surface low near 28N85.5W. A cold front extends from the
low to near 23N88W. A warm front extends from the low across
central Florida. A pre-frontal trough extends from 27N83W to
23N86W. This system is supporting a cluster of moderate 
convection with embedded thunderstorms N of 25N E of 86W. A 
surface trough extends from 23N95W to 20N96W. Scattered showers 
are within 60 nm of the trough axis. Over the next 24 hours the 
low over the NE gulf will cross N Florida. Another piece of energy
at the mid to upper levels will enter the NW Gulf which will 
develop another low over the central Gulf. A cold front will 
accompany this low. Gale force winds are expected behind this 
front over the SW Gulf. Please see the special features section 
for more details. 


A surface trough extends from 18N76W to 11N79W supporting
scattered thunderstorms N of 17N between 73W and 77W. SW flow in
the mid to upper levels and deep moisture support patches of 
scattered thunderstorms over the SW Caribbean. Mainly gentle to
moderate winds cover the western Caribbean. Moderate easterly
winds cover the eastern Caribbean. Over the next 24 hours the 
trough will move west with thunderstorms. 

Deep moisture in mid to upper level SW flow continues to support
showers and isolated thunderstorms over the region. This pattern
will likely continue through tonight, with a possible drying 
trend by late Wednesday as a mid to upper level ridge builds over
the area. 


A cold front enters the area of discussion near 31N55W and extends
to 29N60W where it transitions to a stationary front to near
28N70W, then transitions again to a warm front to central 
Florida. Scattered showers are within 60 nm of the front E of 76W.
Scattered moderate convection is within 90 nm north of the front 
W of 76W. A surface trough extends from 22N66W to 18N69W. This 
trough is interacting with an upper level trough to the west to 
support scattered showers and thunderstorms from 20N to 25N 
between 63W and 76W. A dissipating 1023 mb area of high pressure 
is centered near 30N51W. Another cold front enters the area of 
discussion near 32N24W to 27N25W to 25N30W where it transitions to
a stationary front to a 1012 mb low near 24N38W to 18N50W to 
21N63W. Showers and isolated thunderstorms are within 240 nm SE of
the cold front. Gale force winds are occurring near the cold 
front N of 29N. Please see the special features section for more 
details. Scattered showers are within 90 nm of either side of the 
low and stationary front. Fresh to strong NE winds are within 300 
nm N of the low and stationary front. Over the next 24 hours a new
area of low pressure will develop along the warm front over the W
Atlantic and will move NE. The low over the central Atlantic will
drift SW. 

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Page last modified: Tuesday, 21-Nov-2017 17:52:04 UTC