[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031143
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
742 AM EDT Mon Jul 3 2017

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
1100 UTC.

...TROPICAL WAVES...

A tropical wave is in the Eastern Atlantic with axis near 21W
extending from 07N to 15N, moving slowly westward within the last
24 hours. No significant deep convection is occurring near the
wave, though there are scattered showers within 120 nm of the wave
axis. The wave is embedded in a moist monsoonal flow, as seen in
the Total Precipitable Water imagery, and extends across the
monsoon trough. Little to no surface signature of the wave is
apparent from satellite imagery and limited surface observations,
though the SUNY-Albany Trough Diagnostics depicts the wave at 700
mb well.

A tropical wave is in the central Atlantic with axis near 35W
extending from 05N to 16N, moving west at about 5 kt within the
last 24 hours. A broad 1012 mb surface low appears to have
detached from the wave, which is now a couple hundred miles west
of the low. It is embedded on the wave axis near 10N, as
suggested by low-level cloud motions. The wave also is very
apparent at 700 mb in the Trough Diagnostics. Quite dry conditions
are occurring north of about 12N in the vicinity of the wave, as
seen in the Saharan Air Layer imagery from Meteosat 9. Scattered
moderate and isolated strong convection is occurring from 05N and
10N between 25W and 32W, while scattered showers are seen within
120 nm of the wave axis south of 12N.

A new tropical wave just east of the Lesser Antilles with axis
near 55W extending from 08N to 18W has been added to the Surface
Map. The wave is strongly identified in the Trough Diagnostics,
the Total Precipitable Water imagery, as well as the low-level
cloud motions. Scattered showers and isolated moderate convection
are occurring up to 180 nm ahead of the wave axis between 10N and
15N.

A tropical wave is in the Eastern Caribbean with axis near
71W extending 08N to 18N. The wave is not apparent in either the
surface observations, nor in the Trough Diagnostics. However, it
remains detectable in the Total Precipitable Water imagery as a
maximum east of the wave axis. No significant convection or shower
activity are currently noted with this wave.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough axis extends from the west coast of Africa
near 17N16W to 08N45W. The Intertropical Convergence Zone extends
from 08N44W to 06N57W along northeastern South America.
Convection observed near the Monsoon Trough and ITCZ is mainly
related to tropical waves. Refer to the section above for details.
Otherwise, scattered moderate convection is observed from 05N to
10N between 15W and the West African coast.

...DISCUSSION...

GULF OF MEXICO...

A 1020 mb surface high is over the northeastern Gulf near 28N87W.
Scattered moderate convection is observed within 120 nm of the
trough axis south of 20N. Isolated showers are occurring in the
eastern Gulf within 120 nm of the southwest Florida coast. Winds
throughout the Gulf are fairly tranquil, generally 5 to 15 kt. The
piece of Saharan Air Layer that had moved across the Gulf during
the last couple of days and reached Texas, Louisiana, and
Mississippi appears to still be in place. This should gradually
moisten up, though the overall synoptic pattern should not change
during the next two days.

CARIBBEAN SEA...

The moderate pressure gradient across the Caribbean between the
Bermuda high to the north and the Colombia low to the south is
generally producing 10 to 20 kt tradewind easterlies. The
exception is the 25 kt east to northeasterlies just north of
Colombia. Scattered moderate and isolated strong convection is
located in the southwesternmost Caribbean, south of 11N,
associated with the eastern extension of the Northeast Pacific's
monsoon trough. An upper low is centered over central Cuba, as
seen in both the water vapor imagery as well as the rawindsondes
from Key West, Nassau, Grand Cayman, and Kingston. It is helping
to promote isolated moderate convection over the northwestern
Caribbean including Cuba and the central and southeastern Bahamas.
As the tropical wave along 71W this evening is relatively weak,
this will have little impact on the winds/convection. The upper
low should drift slowly westward during the next couple of days,
enhancing scattered moderate convection from Cuba to the Yucatan
of Mexico.

...HISPANIOLA...

During late afternoon and early evening, scattered moderate
convection occurred over central Haiti and Dominican Republic.
This has since dissipated. With some increased moisture from a
weak tropical wave over the eastern Caribbean, more moderate
convection and showers may occur during the next couple of days.

ATLANTIC OCEAN...

Three tropical waves are analyzed over the basin. Refer to the
Tropical Waves section above for details. The only other area with
significant convection is the scattered moderate convection
occurring over the central Bahamas and the Florida Straits in
association with a vigorous upper-level low over Cuba.
Scatterometer data indicate that a surface trough developed in
association with the upper low. The trough extends from central
Cuba to just east of southeastern Florida. The convection will
likely diminish during the next day as the upper-level low pushes
slowly westward. The remainder of the basin remains under the
influence of a broad Bermuda/Azores high along 35N. This synoptic
pattern will change little through Tuesday.

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

$$
Landsea
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