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Atlantic Tropical Weather Discussion



013 
AXNT20 KNHC 191745
TWDAT 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
145 PM EDT Wed Sep 19 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. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through 
1715 UTC.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 19W/20W from 20N 
southward, moving W at 10 kt. This wave is associated with a 
distinct 700 mb trough. Scattered showers over Africa from 14N- 
18N between 12W-17W. Widely scattered moderate convection is over 
the southern portion of the wave over the Atlantic from 05N-08N 
between 18W-25W.

A surface trough is over the the E Atlantic from 20N28W to 12N31W,
moving NW at 15 KT. This trough has no significant convection. It
is associated with a distinct 700 mb trough.  

A surface trough is over the Atlantic along 46W/47W from 12N 
southward, moving W at 10-15 kt. This trough may be developing a 
surface low. Isolated moderate convection is from 04N-14N between
40W-50W. 

A Caribbean tropical wave is along 64W/65W from 19N southward, 
moving W at 15 kt. Isolated moderate convection is from 10N-17N 
between 58W-64W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes from W Africa near 13N16W, to 12N19W. 
The ITCZ continues from 10N21W to 08N30W to 07N45W. Scattered 
moderate convection is from 04N-10N between 25W-35W.

...DISCUSSION...

GULF OF MEXICO...

The northern extent of a surface trough, the remnants of Isaac, 
is over the Yucatan Peninsula. Scattered moderate convection is
over the Yucatan Channel and the eastern Yucatan Peninsula. Weak
surface ridging is over the remainder of the Gulf of Mexico with
axis along 28N.  

In the upper levels an upper level low is centered over S Texas
near 28N98W. Upper level diffluence is over the W Gulf. Scattered
showers are from 20N-25N between 95W-98W. The remainder of the
Gulf has mostly fair weather. 

The remnants of Isaac will move across the Yucatan Channel
today and move into the southwest Gulf of Mexico Thu and Fri.

CARIBBEAN SEA...

The remnant trough of Isaac extends from 22N86W to the Gulf of
Honduras near 16N88W. Widely scattered moderate convection is over
the NW Caribbean N of 15N between 79W-89W. 

Scattered moderate to isolated strong convection is over the SW 
Caribbean S of 15N between 77W-87W. The monsoon trough is along 
09N over Costa Rica and Panama enhancing convection. 

A tropical wave is over the E Caribbean. See above. This tropical 
wave will move west across the central Caribbean Thu into Fri, 
and pass west of the area through late Sat into Sun. Strong gusts 
are possible near showers and thunderstorms associated with this 
tropical wave near the Lesser Antilles and eastern Caribbean. 
Meanwhile high pressure building from the central Atlc into the 
central Bahamas will support moderate to fresh trade winds and 
building seas across the entire basin late Wed through Fri. 

ATLANTIC OCEAN...

A quasi-stationary front is off the coast of Georgia. Scattered
moderate convection is from 29N-31N between 74W-78W. A surface
trough is further E from 34N64W to 28N68W. Scattered showers are
within 90 nm of this trough. A 1022 mb high is centered over the
central Atlantic near 28N49W. The remnant low of Joyce is over the
E Atlantic near 30N29W. Scattered showers are within 120 nm of the
center. 

Of note in the upper levels, an upper level low is centered over
the W Atlantic near 31N66W enhancing convection. 

Low pressure moving off the Carolinas tonight will drag an 
attendant frontal trough across the NW Atlantic waters north of 
27N Thu and Fri. The low will sink to near 31N67W Fri evening then
drift W and slowly weaken Sat and Sun. NE swell will dominate 
waters N of 26N over the weekend. 

For additional information please visit 
http://www.hurricanes.gov/marine

$$
Formosa