[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 270005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Thu Jul 26 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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...TROPICAL WAVES...

A tropical wave is near the Cabo Verde Islands with axis
extending from 05N-18N along 26W, moving westward at 10-15 kt.
Shallow moisture near the monsoon trough supports scattered
showers from 05N-10N between 24W-30W. The remainder of the wave
environment lacks convection due in part to the presence of
Saharan dry air and dust.

A tropical wave is over central Atlantic with an axis extending
from 04N-20N along 39W, moving westward at 10-15 kt. A large
outbreak of Saharan Air Layer continue to hinder convection from
developing nearby the wave.

A tropical wave is over the central Atlantic with an axis
extending from 06N-18N along 54W, moving westward at 10-15 kt. Strong
deep layer wind shear and Saharan dry air and dust are hindering
deep convection to develop at the time.

A tropical wave is over the central Caribbean with axis along 72W,
moving W at 10-15 kt. Precipitable water satellite imagery shows
a very dry environment across the central Caribbean, which along
with strong deep layer wind shear are hindering convection S of
Hispaniola.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of Africa near
12N16W to 08N23W to 07N34W. The ITCZ extends from 04N40W to
07N53W. Aside from convection associated with the tropical waves,
scattered moderate convection is from 06N-10N E of 21W.

...DISCUSSION...

GULF OF MEXICO...

An upper level trough prevails across the E Gulf with its base
extending SW from central Florida to the Bay of Campeche. This
trough supports a weakening stationary front that extends from S
Alabama to SE Louisiana. It also supports a surface trough that
extends from 27N82W to 24N88W. Scattered showers are within 120 nm
S of the trough. The front is transitioning to a surface trough.
Both troughs are expected to lift north through tonight.
Otherwise, the Atlantic subtropical ridge covers the remainder of
the SE Gulf and will continue to build northwestward across the
remainder of the basin through the weekend. Light to gentle
variable flow will dominate the basin during this time period.

CARIBBEAN SEA...

A weak upper level low centered near Jamaica along with shallow
moisture in the NW Caribbean support scattered showers and tstms N
of 17N between 75W and 83W. In the SW basin, the monsoon trough
supports numerous showers and tstms S of 11N. A tropical wave is
crossing the central Caribbean waters. Please refer to the
tropical waves section above for further details. GOES-16 water
vapor imagery continues to indicate very dry conditions across the
remainder of the basin while enhanced RGB satellite imagery
indicates a thin layer of Saharan Air Dust moving across the area.
Strong deep layer wind shear is also noted in the E Caribbean.
These hostile factors are suppressing convection across the
remainder of the Caribbean basin. A new tropical wave is forecast
to move across the Lesser Antilles Friday night, with showers and
thunderstorms beginning to spread across the southern Leeward
islands starting this evening in advance of the wave.

ATLANTIC OCEAN...

Three tropical waves are moving across the basin. Please refer to
the tropical waves section above for more details. Scattered
showers and tstms N of 23N W of 75W are being supported by an
upper trough along the eastern United States that extends across
the Florida peninsula. This upper trough will prevail through
Friday, enhancing shower and thunderstorm activity over this
area. Farther east, an upper level low supports a surface trough
that extends from 31N63W to 28N66W. These features support a broad
area of cloudiness with scattered showers and isolated tstms from
20N to 31N between 62W and 70W. The Atlantic subtropical ridge
dominates the remainder of the basin being anchored by a 1030 mb
high centered near 37N54W. 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

$$
ASL/NAR
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