[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 312349
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
749 PM EDT Tue Jul 31 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 in the E Atlc with axis extending from 08N-18N
along 23W, moving W at 10 kt. The wave is in a low deep layer
wind shear environment, however is being severely affected by a
Saharan Air Layer outbreak as depicted by GOES-16 RGBs and CIRA
LPW imagery. Shallow moisture and middle level diffluence support
scattered showers S of the monsoon trough from 05N-09N between
22W-30W.

A tropical wave is in the central Atlc with axis extending from
07N-17N along 37W, moving W at 10-15 kt. The wave is in a low
deep layer wind shear environment, however is being severely
affected by Saharan Air Layer dry air and dust as depicted by
GOES-16 RGBs, low-level water vapor and CIRA LPW imagery. No
significant convection is associated with this wave at this time.

A tropical wave in the central Atlc with axis extending from 06N-
16N along 54W, moving W at 15-20 kt. The wave is being supported
by a middle to upper level inverted trough and is mainly in a dry
air environment as depicted by GOES-16 RGBs and CIRA LPW imagery.
Moderate moisture in the southern wave environment associated with
the ITCZ supports scattered showers from 09N-11N and west of 55W.

A tropical wave is in the central Caribbean with axis extending S
of 21N along 78W, moving W at 15-20 kt. The wave is mainly in a
strong deep layer wind shear environment and Saharan dust is noted
across the central Caribbean in GOES-16 RGBs imagery. However,
CIRA LPW imagery show abundant low-level moisture associated with
this wave, which along diffluence aloft support scattered
moderate convection between Colombia and S Panama S of 12N. An
upper-level low centered E of Jamaica support isolated showers
across Hispaniola and the Windward Passage.

A tropical wave is moving off the Yucatan Peninsula into the E Bay
of Campeche. Its axis is S of 24N along 93W, moving W at 10-15
kt. The wave is being supported by a middle-level inverted trough
that along with shallow moisture support scattered showers in the
SW Gulf S of 25N W of 90W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 18N16W
to 09N21W to 09N35W. The ITCZ begins near 08N38W and continues to
09N53W, then resumes W of a tropical wave near 09N56W and
continues to the coast of Venezuela near 09N63W. Aside from the
convection associated with the tropical waves, scattered showers
are from 07N-10N from 26N-34N.

...DISCUSSION...

GULF OF MEXICO...

The Atlc subtropical high continues to extend a ridge axis SW
across the Florida Peninsula to the central Gulf, thus supporting
light to gentle south-southeasterly flow. CIRA LPW imagery show
very moist air at the lower levels across the basin, which is
being advected from the Caribbean by the return flow. This moist
environment along with diffluence aloft support scattered showers
and tstms N of 23N E of 90W. In the E Bay of Campeche, a tropical
wave support scattered showers. See tropical waves section for
further details. Elsewhere, scattered showers and tstms are
within 90 nm off the SE coast of Texas and SW coast of Louisiana
associated with a frontal system N of the area and anchored by a
1015 mb low in NE Texas. This front is forecast to come off the
coast of Texas Wed morning, stall from SW Louisiana to near
Tampico, Mexico Thu morning and weakening to a surface trough late
Thu night. Showers are forecast to continue in the aforementioned
regions through early Fri.

CARIBBEAN SEA...

Abundant shallow moisture is in the NW and central Caribbean as
noted in CIRA LPW imagery. This moisture along with middle to
upper level diffluence is supporting scattered showers and tstms N
of 18N between 79W-86W. Similar convection is in the SW basin S of
12N between 74W-84W, which is associated with the EPAC monsoon
trough that connects to a 1011 mb low off the coast of Colombia
near 11N75W. An upper level low off the E coast of Jamaica
support isolated showers over western Dominican Republic, Haiti
and the Windward Passage. GOES-16 water vapor and RGB imagery show
dry air and dust across the E basin, which in part is hindering
the development of convection. A new tropical wave is forecast to
move across the Lesser Antilles Thu with showers for the Windward
Islands. Another tropical wave will move into the E Caribbean on
Sunday with showers.

ATLANTIC OCEAN...

Three tropical waves move across the basin, see section above.
Otherwise, the Atlc subtropical high dominates the basin, thus
supporting mainly fair weather conditions. Surface ridging will
dominate the central and eastern Atlantic through the next couple
of days providing stable and dry conditions.

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

$$

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