[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150006
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
806 PM EDT Sat Jul 14 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.

...SPECIAL FEATURES...

Subtropical storm Beryl is centered near 37.3N 65.2W as of
14/2100 UTC or about 345 mi north of Bermuda, moving NE at 12 kt.
Estimated minimum central pressure is 1010 mb. Maximum sustained
wind speed is 35 kt with gusts to 45 kt. Little change in
strength is forecast through Sunday. After that, Beryl should
weaken as it moves over colder water, and the cyclone is expected
to degenerate into a remnant low pressure area by Monday. Scattered
moderate convection is within 120 nm north and south of the
center. Refer to the latest NHC Forecast/Advisory under AWIPS/WMO
headers MIATCMAT2/WTNT22 KNHC and high seas forecasts issued by
the National Weather Service under AWIPS header NFDHSFAT1 and WMO
header FZNT01 for more information.

SW Caribbean gale warning off the coast of Colombia: NE gale
force winds are forecast to resume near 0600 UTC Sun and continue
through Sun afternoon hours. The pressure gradient will tighten
up again Sun evening, and gale force winds will resume once more
into early Mon within the same area. Model guidance indicates
that these winds will once again pulse to minimal gale force Tue
night until early on Wed morning. Seas are expected to build to
the range of about 10-14 ft with these wind conditions. Please
read the High Seas Forecast, under the AWIPS/WMO headers
HSFAT2/FZNT02 KNHC, for more details.

...TROPICAL WAVES...

An E Atlantic tropical wave has its axis along 22W from 05N to
18N, moving westward at 10-15 kt. Scattered moderate convection is
in the southern wave environment associated with the monsoon
trough. This convection is from 06N-10N between 17W-31W. The
remainder wave environment lacks convection as it continues under
the influence of Saharan dry air and dust.

A central Atlantic tropical wave has its axis extending from near
05N53W to 21N49W, moving W at 15-20 kt. The wave continues to
move through a rather dry and stable environment, and is void of
deep convection.

A central Caribbean Sea tropical wave has its axis along 70W, moving
W at 15 kt. The wave is supporting scattered moderate isolated
strong convection in NW Haiti and isolated showers over the
central Caribbean between 66W and 74W. The leading edge of the
Saharan Air layer (SAL) as noted from Univ. of Wisconsin CIMSS and
as observed in the GOES-16 RGB Geocolor and dust images has
entered the far eastern Caribbean Sea in the wake of the wave.

A central Caribbean Sea tropical wave has its axis along
78W, moving westward near 15 kt. Its northern extent reaches to
eastern Cuba where it supports scattered showers. No convection is
noted elsewhere.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coastal areas of Africa
near 10N14W to 07N30W, where latest scatterometer data indicates
that it transitions to the ITCZ to 08N40W to 08N58W. For
information about convection see the tropical waves section.

...DISCUSSION...

GULF OF MEXICO...

High pressure ridging from a 1021 mb high center at 26N91W as of
18Z continues to dominate the basin allowing for generally light
to gentle anticyclonic flow to prevail through most of next week.
Seas will remain on the rather low side, generally under 5 ft.
Gentle to moderate southeast to south winds will continue over the
western part of the gulf through the next few days. Per latest
GOES-16 RGB Geocolor imagery, African dust has reached the SE
Gulf, including the Yucatan Channel. A surface trough will move
westward off the Yucatan Peninsula each evening through Wednesday.
It will enhance nocturnal winds in the SW corner of the Gulf.

CARIBBEAN SEA...

Two tropical waves will continue to move across the basin. Refer
to the Tropical Waves section above for details.

A gale warning is in effect for the waters near the coast of
Colombia. Refer to the Special Features section above for more
information on this event.

The tropical wave along 78W will move across the remainder of the
central through early this evening, then across the western
Caribbean tonight through Mon night. The eastern Caribbean Sea
tropical wave along 66W/67W will move through the rest of the
eastern Caribbean Sea through Sun afternoon. Drier air and haze
attributed to the Saharan Air Layer (SAL) will filter across the
eastern and central Caribbean in the wake of the wave into Mon.
The shower and thunderstorm activity may be further aided by an
upper-level trough that extends from the Mona Passage to the far
SW Caribbean. An extensive area of dry sinking air is evident on
water vapor imagery to the west of the trough. This wave is
forecast to move across the central Caribbean Sun night tonight
through Mon night and the western Caribbean Tue. This wave is
expected to lack deep convection as it moves across the central
and western Caribbean as it will be moving through a very dry and
stable environment. The gradient behind the waves will tighten
enough to freshen trade winds across the central Caribbean Sea
well into next week.

ATLANTIC OCEAN...

Newly formed subtropical storm Beryl is well north of the area.
See Special Features section above for the latest information on
this system.

A surface trough extends from 32N68W 28N72W and to the
northwestern Bahamas. Scattered to numerous showers and
thunderstorms are noted southeast and south of the trough north of
27N between a line from 32N62W to 27N65W and 73W. The trough will
move little through Sun night while weakening.

The remainder of the Atlantic forecast area is under the
influence of the Bermuda-Azores High, with a center of 1033 mb
located WNW of the Azores near 37N41W. Its associated ridge
extends southwestward to the northeastern Caribbean and the SE
Bahamas. High pressure building westward from the central
Atlantic through Tue will support fresh to strong trade winds
south of 23N W of 65W. Winds will pulse to strong north of
Hispaniola at night this weekend. High pressure building
westward from the central Atlantic Ocean through Wed will
support fresh to strong trade winds south of 23N. The winds will
pulse to strong north of Hispaniola at night through early
Mon.

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

$$
JA/NR
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