[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040606
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
206 AM EDT Sat Aug 4 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 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...TROPICAL WAVES...

A tropical wave is off the coast of Africa with axis extending
from 06N-18N along 19W. The wave is in a low deep layer wind
shear environment N of 10N, however is being affected by intrusion
of Saharan dry air and dust as indicated by GOES-16 RGB imagery
and by CIRA LPW imagery. Shallow moisture and diffluence aloft
support scattered to isolated showers from 05N-15N E of 23W.

A tropical wave is in the E Atlc with axis extending from 03N-17N
along 25W, moving W at 10-15 kt. The wave is in a low deep layer wind
shear environment N of 05N, however is being affected by
intrusion of Saharan dry air and dust as indicated by GOES-16 RGB
imagery and by CIRA LPW imagery. Shallow moisture and diffluence
aloft support scattered showers from 05N-14N between 23W and 32W.

A tropical wave is in the central Atlc with axis extending from
07N-18N along 52W, moving W at 10-15 kt. The wave is in a strong
deep layer wind shear environment and is being affected by
intrusion of dry air and dust, which is limiting convection to
isolated showers and tstms from 10N-14N between 50W and 58W.

A tropical wave is in the E Caribbean with axis extending from
10N-19N along 67W, moving W at 15-20 kt. The southern half of the
wave environment is in a strong deep layer shear environment and
GOES-16 RGB show Saharan dust affecting the entire wave. However,
the wave in underneath an upper level low that along with shallow
moisture support isolated showers from 13N-19N between 60W and
69W...including the Puerto Rico and the Lesser Antilles.

A tropical wave is in the W Caribbean with axis S of 20N along
82W, moving W at 15 kt. The southern half of the wave is in a low
to moderate deep layer wind shear environment that along with
abundant low level moisture and upper level divergence support
scattered showers and tstms from 10N-17N between 80W-85W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 13N17W to 12N20W to 10N25W to
10N38W. The ITCZ begins near 06N37W and continues to
04N52W. Please refer to the TROPICAL WAVES section for
information about precipitation.

...DISCUSSION...

GULF OF MEXICO...

A middle to upper level trough extends from Michigan SW to a base
over NE Mexico. To the SE of the trough base, the northern
periphery of an upper level ridge generates diffluent flow across
the western half of the basin, thus supporting isolated showers.
Scattered showers and tstms are in the eastern Bay of Campeche
ahead of a surface trough that will come off the Yucatan Peninsula
later this morning. This trough is enhancing winds in this region
to fresh. CIRA LPW imagery show abundant low level moisture
advecting from the SW N Atlc to the SE Gulf where along with
middle level diffluent flow support scattered showers and tstms E
of 87W. Otherwise, the SW periphery of the N Atlc Subtrpcl ridge
extends across most of the gulf, thus providing light to gentle SE
wind. No major changes are expected during the weekend.

CARIBBEAN SEA...

CIRA LPW and GOES-16 water vapor imagery at the lower levels
indicate that mostly shallow moisture is across the Caribbean,
except for the far W basin. In the W Caribbean, a tropical wave
support showers and tstms off the coast of Nicaragua and Honduras
while an upper level low support scattered heavy showers and tstms
over adjacent waters of central Cuba. In the SW basin, the EPAC
monsoon trough support numerous heavy showers and scattered tstms
within 60 nm of the coast of Colombia and southern Panama. A
second tropical wave moves over the E Caribbean, however lacking
deep convection partly due to strong wind shear and Saharan dry
air and dust moving across this region. For further information
on the waves...see section above. Otherwise, ridging N of the area
is supporting fresh to strong winds in the south-central basin.
The trpcl wave over the W basin will move to the EPAC Sun night
while a new wave enters the E Caribbean.

ATLANTIC OCEAN...

A surface ridge dominates the SW N Atlc waters with a weakness
analyzed as a surface trough NE of the northern Bahamas. Farther
east, a weak cold front extends from 30N54W to 30N63W. Ahead of
the front, a surface trough extends from a 1017 mb low located
near 31N44W. Scattered showers and tstms are within the front and
this trough to the N of 27N. Otherwise, aside from the tropical
waves already discussed, surface ridging dominates elsewhere. The
cold front will continue to move into the area through Sun night
when is forecast to weaken and then dissipate Mon night.

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

$$
Ramos
This weather bulletin was brought to you by:
www.nashvilleweather.net