[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271156
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
755 AM EDT Fri Jul 27 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 0600 UTC surface analysis and satellite imagery through
1145 UTC.

...TROPICAL WAVES...

A tropical wave is west of the Cabo Verde Islands with axis
extending from 06N-16N along 30W, moving W at 10-15 kt. The wave
is being covered by a Saharan air layer outbreak, which dry air
and dust suppresses convection mainly N of 10N. Shallow moisture
associated with the monsoon trough and diffluence in the upper
levels support scattered moderate convection from 06N-10N between
30W- 35W.

A tropical wave is over central Atlantic with axis extending from
05N-17N along 41W, moving westward at 10-15 kt. Intrusion of
Saharan dry air and dust to the wave environment hinders
convection at the time.

A tropical wave is over the central Atlantic with axis extending
from 06N-19N along 56W, moving westward at about 10 kt. Similar
to the tropical wave to the E, Saharan dry air and dust hinders
convection at this time.

A tropical wave is over the central Caribbean with axis S of 21N
along 76W, moving W at 10-15 kt. Both GOES-16 water vapor imagery
and CIRA LPW imagery at lower levels show a very dry environment
in this region. Scattered showers are noted along the southern
portion of the wave where it meets the monsoon trough S of 11N.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 12N17W
to 07N27W to 05N38W. The ITCZ extends from 06N42W to 06N54W.
Scattered showers are noted alog the axis between 16W-25W.

...DISCUSSION...

GULF OF MEXICO...

The Atlantic subtropical ridge extends an axis SW across the
Florida peninsula and into the E Gulf, thus supporting light to
gentle variable winds basin-wide. A surface trough is moving over
the Bay of Campeche this morning enhancing winds in the eastern
half of the SW gulf to moderate levels. The trough will then
dissipate later this morning. This feature will continue the next
several night with winds increasing to locally fresh at times.
GOES-16 water vapor imagery at lower levels show very dry air in
the Gulf. Surface ridging will prevail across the basin through
the weekend. Otherwise, isolated showers and tstms are likely in
the Bay of Campeche associated with a tropical wave that will move
into this region Sunday.

CARIBBEAN SEA...

Shallow moisture in the NW Caribbean, low deep layer wind shear
along with a divergent environment aloft are supporting heavy
showers and tstms within 90 nm off the coast of Cuba. In the SW
Caribbean, the EPAC monsoon continue to support scattered showers
and tstms within 105 nm of the coast of NW Colombia, Panama and
Costa Rica. Isolated showers are occurring in the northern Leeward
Islands and the Virgin Islands being supported by diffluence aloft
associated to an upper level low NE of Puerto Rico. A tropical
wave moves over the central basin, however general hostile
conditions across the basin associated with strong shear and dry
air hinder convection at the time. See the waves section for
further details. A new tropical wave is forecast to move across
the Lesser Antilles tonight, and a second wave will enter the E
Caribbean Sun night. Otherwise, fresh to strong winds are forecast
for the south-central basin through the weekend.

ATLANTIC OCEAN...

Three tropical waves are moving across the basin. Please refer to
the section above for more details. Diffluent flow between the
base of an upper trough over the SE CONUS and a high over the
northern Bahamas continue to support scattered showers and tstms N
of 23N W of 70W. The upper-level trough will prevail through
today, enhancing shower and thunderstorm activity over this area.
Farther east, a middle level low just N of Hispaniola supports a
surface trough that extends from 20N68W to 26N67W along with
scattered showers and isolated tstms from 21N to 27N between 65W
and 70W. The Atlantic subtropical ridge dominates the remainder of
the basin being anchored by a 1030 mb high centered near 37N53W.
Surface ridging will dominate the central and eastern Atlantic
through the end of the week providing stable and dry conditions.

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

$$

Ramos/ERA
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