[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
204 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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...SPECIAL FEATURES...

What was earlier an area of low pressure associated with the
remnants of Beryl has regenerated into subtropical storm Beryl
centered near 36.4N 65.7W as of 14/1700 UTC or about 250 nm north
of Bermuda, moving NE at 10 kt. Estimated minimum central pressure
is 101 mb. Maximum sustained wind speed is 35 kt with gusts to 45
kt. Beryl is forecast to maintain intensity through Sun, then
weaken to a depression afterwards as it continues on a
northeastern track motion over cold water. Satellite imagery shows
scattered moderate isolated strong convection within 180 nm
north- northeast 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 coast of Colombia: NE gale-force
winds that occurred within 90 nm off the coast of Colombia
during the overnight hours have diminished to strong to near
gale force. Resultant seas with the recent gale force winds are
in the 10-13 ft range from 11N-14N between 74W and 75W. The
pressure gradient will tighten up again tonight into early Sun,
and from Sun night into early Mon to allow for a repeat pulsing
of the NE gale force winds to once again develop 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...

A far eastern Atlantic broad tropical wave has its axis along 22W
from 07N to 19N, moving westward at 10-15 kt. Both satellite
imagery and 700 mb model diagnostic guidance correlate very well
with respect to the location of this wave. The satellite imagery
shows scattered moderate convection within about 270 nm to the
west of the southern segment of the wave's axis within 60 nm of
the monsoon trough axis. Similar convection is behind the wave
from 07N-11N east of 20W to the coast of Africa.

A central Atlantic tropical wave has its axis extending from near
20N48W to 10N51W. This wave is observed as having a broad
inverted-V shape cloud structure as seen in satellite imagery as
it moves westward at 15-20 kt. The wave is moving through a rather
dry and stable environment, and is void of deep convection.
Isolated showers are possible from 10N-14N between 47W-51W.

An eastern Caribbean Sea tropical wave has its axis along 66W/67W
S of 19N, moving westward around 16 kt. The northern portion is
passing just to the south of Puerto Rico. Expect increasing
moisture with scattered showers and isolated to affect some areas
of the eastern Caribbean into tonight. 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 76W/77W,
moving westward at 15 kt. Its northern extent reaches to eastern
Cuba. No significant deep convective precipitation is noted in
latest satellite imagery, however isolated showers moving quickly
westward are possible near the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from through the coastal areas of
Guinea Bissau near 11N15W to 10N20W and 09N29W, where latest
scatterometer data indicates that it transitions to the ITCZ to
08N38W to 09N48W to 09N55W to 09N60W. Aside from convection
associated with the tropical wave along 22W, only scattered
moderate convection is seen within 150 nm south and 60 nm north
of the ITCZ between 41W-43W.

...DISCUSSION...

GULF OF MEXICO...

High pressure ridging from a 1021 mb high center at 26N91W as of
15Z 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 76W/77W 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 the next
few days.

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

$$
Aguirre
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