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Atlantic Tropical Weather Discussion

AXNT20 KNHC 231013

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Mon Nov 23 2020

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 0600 UTC surface analysis and satellite imagery through 
1000 UTC.


A tropical wave extends its axis along 89W and from 20N southward, 
moving westward at 10 to 15 kt. The wave combined with middle 
level divergent flow continues to produce scattered showers and 
tstms over the W Caribbean, mainly west of 78W. 


The monsoon trough extends from the coast of West Africa near 
11N16W to 10N20W. The ITCZ begins near 10N20W and continues 
to 01N50W. Scattered moderate convection is noted within 100 nm on
either sides of the boundaries.


A cold front has entered the northern Gulf, extending from 30N88W
to 29N91W to 28N97W. Weak surface ridging ahead of the cold front
continue to support gentle to moderate northeasterly winds over 
the eastern half of the basin, while moderate to locally fresh
northeasterly winds prevail over the western half of the basin. 
Water vapor and low level precipitable water imagery depict very 
dry conditions that continue to support fair weather basin-wide. 
Seas are in the 3 to 5 ft range as indicated by recent altimeter 

The cold front will continue moving quickly across the basin 
while weakening. High pressure will build in the wake of the 
front. Fresh southerly return flow will set up over the western 
Gulf tonight through Tue night ahead of the next cold front 
forecast to reach the northern Gulf late on Wed, then stall and 
lift northward Thu. Looking ahead, a third and stronger cold front
is expected to move across the Gulf waters over the weekend. 


A tropical wave moving over the far west Caribbean along with 
divergent flow aloft continue to support scattered showers and 
tstms over that region. Latest scatterometer data depict light to
gentle winds across the western Caribbean, while moderate to fresh
trades are noted east of 73W. Dry air at the middle levels is 
supporting fair weather elsewhere. 

Seas are 3 to 5 ft over the western half of the Caribbean, 5 to 7
ft E of 74W, and 8 to 9 ft over the Atlantic waters east of the
Lesser Antilles. 

Moderate easterly winds and seas in the 8-9 ft range
will continue to impact the waters east of the Lesser Antilles 
through today. Building high pressure north of the area will 
bring an increase in winds and seas across the south-central 
Caribbean Tue through Thu. Fresh to strong NE winds are expected 
across the Windward passage and south-central Caribbean Tue 
night through Thu night.


Latest scatterometer data continues to depict the surface trough 
extending from 30N68W to 22N71W. Moderate to fresh E to SE winds
prevail east of the trough axis, as well as scattered showers and
tstms between 55W-70W.

There is a slight chance that the surface trough could acquire 
some subtropical characteristics as it moves northeastward over 
the next day or so. On Tuesday, however, the disturbance is 
expected to merge with a cold front. Later in the week, this 
system may have a second opportunity to develop subtropical 
characteristics if it becomes separated from the front and 
meanders over the central Atlantic.

Over the east Atlantic, a surface trough is about 600 nm west of 
the Canary Islands along 31N28W to 26N30W, which is supporting 
scattered showers and tstms N of 28N between 24W and 29W. The 
remainder subtropical Atlantic is under the influence of a surface
ridge that supports generally moderate trade winds.