[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161803
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
203 PM EDT Thu Aug 16 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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...SPECIAL FEATURES...

The center of Subtropical Storm Ernesto at 16/1500 UTC is near
42.0N 43.2W, or 510 nmi to the ESE of Cape Race in Newfoundland.
Ernesto is moving NE at 14 knots. The estimated minimum central
pressure is 1007 mb. The maximum sustained wind speeds are 40
knots with gusts to 50 knots. Scattered moderate convection is
from 39N to 46N between 39W and 44W. Please read the latest NHC
forecast/advisory under AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC
for more details.

...TROPICAL WAVES...

A tropical wave is in the E Atlc with axis extending from 06N-17N
along 23W, moving W at 10 kt. The wave is in a moderate deep
layer wind shear environment, and CIRA LPW imagery shows dry air
affecting the wave. These two factors are contributing to the
lack of convection at this time.

A tropical wave is in the central Atlc with axis extending from
04N-16N along 49W, moving W at 20 kt. The wave is in a low deep
layer wind shear environment, and CIRA LPW imagery shows abundant
low level moisture associated with it. These factors along with
upper level diffluence support scattered moderate convection and
isolated tstms from 07N-18N between 46W-60W.

A tropical wave is in the E Caribbean with axis extending from
09N-18N along 65W, moving W at 15-20 kt. The wave is in a
moderate to strong deep layer wind shear environment. GOES-16
water vapor imagery at the lower levels show very dry air over
this region of the Caribbean. There is no convection associated
with this wave at this time.

A tropical wave is in the Yucatan Peninsula S of 21N with axis
along 89W, moving W at 10-15 kt. GOES-16 water vapor imagery at
the lower levels shows very dry air over this region, which in
part is hindering convection at the time.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of W Africa near
12N16W to 09N29W. The ITCZ begins near 09N29W and continues to
10N36W to 11N47W. Scattered moderate isolated strong convection is
from 11N-14N E of 18W. Isolated moderate convection is within 120
nm either side of the ITCZ between 27W-37W. For more information
about convection, see the tropical waves section.

...DISCUSSION...

GULF OF MEXICO...

The Bermuda high extends a ridge axis SW across Florida and large
portions of the Gulf to 96W, and weak winds in the range of 5-10
kt prevail in the region. Inflow of shallow moisture from the
Caribbean by southeasterly wind along with a middle level inverted
trough in the E basin support scattered showers and tstms N of
24N E of 90W. Winds in this region may be slightly higher in the
range of 15-20 kt enhanced by the convection. Otherwise, a surface
trough is in the W Bay of Campeche supporting scattered heavy
showers and tstms within 75 nm of the coast of Vera Cruz. Surface
ridging will prevail across the basin through early next week.
Showers over the NE basin are forecast to continue through Sat
night.

CARIBBEAN SEA...

CIRA LPW imagery shows abundant shallow moisture across most of
the Caribbean. In the western basin, diffluent flow aloft supports
a broad area of scattered showers and tstms from 11N-18N W of 76W.
A tropical wave is moving across the E basin, however both
Saharan Air Layer dry air and strong deep layer wind shear are
suppressing the development of convection at the time. Otherwise,
surface ridging extending from the Atlc continues to support
fresh to near gale force winds in the south-central Caribbean that
is forecast to continue the next two days...strongest winds will
be along the coast of Colombia. A tropical wave within 700 nm SE
of the Lesser Antilles will move across the Islands Sat morning
along with showers.

ATLANTIC OCEAN...

The Bermuda high and the Azores high covers most of the Atlc ocean
mainly supporting fair weather. A weakness in the ridge is
analyzed as a 1019 mb low centered near 32N55W from which a
surface trough extends SW to 24N63W. Scattered showers and tstms
are within 150 nm ahead of the low and trough N of 27N. A large
area of disorganized showers and thunderstorms is SE of Lesser
Antilles associated with a tropical wave. Some development of
this system is possible over the next couple of days while it
moves west-northwestward toward the Windward Islands. By late
Saturday, unfavorable environmental conditions should limit the
chances for additional development while the system moves over the
eastern Caribbean Sea. Regardless of development, this system is
likely to bring locally heavy rainfall to portions of the Lesser
Antilles on Friday and Saturday. For further information
associated with the tropical waves, see section above.

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

$$
Ramos/Hagen
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