[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152353
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
753 PM EDT Fri Jun 15 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 Atlantic, with axis extending from
12N29W to 04N31W, moving W at 10 kt. The wave shows up well as a
low amplitude moisture surge on the TPW product. The GOES-16
Geocolor RGB imagery shows the presence of the Saharan dust and
dry air N of the wave at 15N. Isolated showers are noted where
the wave meets the ITCZ.

A tropical wave is in the central Atlantic, with axis extending
from 14N45W to 04N46W, moving W at 10-15 kt. The wave is well
depicted in the TPW product. Shallow moisture and isolated showers
are near the wave's axis.

A tropical wave is moving westward across the eastern Caribbean.
Its axis extends 61W/62W. African dust also surrounds the wave.
As a result, shallow moisture with embedded showers is associated
with the wave. Moisture related to this system will reach Puerto
Rico late today into tonight, and Hispaniola early on Sun,
increasing the likelihood of showers and isolated tstms.

A tropical wave is over the W Caribbean, with axis along 83W from
10N-19N, moving W at 10-15 kt. Scattered showers and tstms are
seen over the SW Caribbean, likely a combination of the wave and
the proximity of the Monsoon Through. The wave will move westward
into Central America through Sat, helping to induce some shower
and tstm activity. The GFS model indicates plenty of moisture over
Central America this upcoming weekend.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 11N15W
to 07N25W. The ITCZ continues from 07N25W to 07N29W, then resumes
west of a tropical wave from 07N32W to 08N45W then from 07N47W to
06N57W. Besides the convection mentioned in the Tropical Waves
section, scattered moderate convection is noted within about 75 nm
S of the monsoon trough between 14W-22W. Similar convection is
also seen from 07N-09N between 37W- 40W.

...DISCUSSION...

GULF OF MEXICO...

A surface trough is analyzed over the SW Gulf and extends from
23N95W to the central Bay of Campeche near 19N93W. Scattered
showers and isolated thunderstorms are noted over the western Gulf
under a SE wind flow. An upper-level low centered over the
western Gulf is helping to induce this convective activity. A
large area of cloudiness with embedded showers and tstms is
affecting the far SE Gulf, including parts of the Yucatan
Peninsula and the Yucatan Channel. A ridge dominates the
remainder of the Gulf waters.

The surface trough across the Bay of Campeche and western Gulf
will shift WNW moving inland of Mexico by this evening. The second
and stronger trough will shift from the NW Caribbean through NW
Gulf tonight through Sun, accompanied by widespread convection. A
tightening pressure gradient E of this second trough will induce
fresh SE winds in west-central Gulf waters tonight, becoming
strong to near gale in the central Gulf this weekend, spreading W
through early next week.

CARIBBEAN SEA...

A large area of disorganized showers and thunderstorms over the
northwestern Caribbean Sea and the Yucatan Peninsula is associated
with a surface trough. While significant development of this
system is not anticipated, heavy rain and strong gusty winds are
occurring across the Yucatan Peninsula today, and will overspread
the central Gulf of Mexico on Saturday and reach portions of the
Texas and southwestern Louisiana coasts by Sunday. A diffluent
pattern aloft is currently helping to induce this convective
activity. Scattered showers and tstms are also seen over the SW
Caribbean just N of Panama. Two tropical waves are moving westward
across the basin. Please, see Tropical Wave section for details.

Recent scatterometer data provided observations of fresh to strong
winds across the central Caribbean, with seas of 10-11 ft. The
aerial extent of the strong trades, roughly between 70W and 83W,
will slightly diminish this weekend. However, fresh to strong
winds will persist across the Gulf of Honduras and the NW
Caribbean over the next couple of days in association with the
surface trough.

ATLANTIC OCEAN...

As of 1500 UTC, a surface trough is located E of Florida, and
extends from 31N77W to 27N80W. Scattered showers and tstms are
near and ahead of the trough. Farther E, a stationary front enters
the forecast region near 31N54W and extends SW to near 27N60W. An
upper-level low is generating some showers and isolated tstms just
E of the frontal boundary. The remainder of the Atlantic Ocean is
under the influence of a ridge, anchored by a 1030 mb high pressure
located SW of the Azores near 36N32W.

The trough offshore of northern and central Florida will be
overtaken by a backdoor cold front this weekend, which will move
S through early next week. The high pressure ridge located S of
these boundaries will sink southward ahead of the features. New
high pres is forecast to build from N of the area by Tue.

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

$$

GR/ERA
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