[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280531
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
131 AM EDT Fri Sep 28 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...SPECIAL FEATURES...

Satellite images, radar data, aircraft data, and surface observations
all indicate that Kirk's center made landfall on St. Lucia around
0030 UTC. Now, the center of Kirk is moving into the eastern Caribbean
Sea. Heavy rainfall and strong winds will continue to spread across
portions of the Lesser Antilles overnight. Tropical Storm Kirk is
centered near 13.8N 61.4W at 28/0300 UTC. It is moving toward the
west or 260 degrees 10 knots. Estimated minimum central pressure
is 1002 mb. Maximum sustained wind speed is 45 knots with gusts
to 55 knots. This tropical cyclone is expected to produce total
rainfall of 4 to 6 inches across the northern Windward and
southern Leeward Islands, with isolated maximum totals up to 10
inches across Martinique and Dominica. These rains may produce
life-threatening flash floods and mudslides. Across Saint Croix
and eastern Puerto Rico, Kirk is expected to bring 2 to 4 inches
with isolated maximum totals of 6 inches by Friday and Saturday.
Currently, satellite imagery indicates a band of numerous moderate
and isolated strong convection within 60 nm NW semicircle of
center. Numerous moderate to isolated strong convection is also
noted elsewhere from 11.5N- 15N between 56W- 61W. Gradual
weakening is anticipated during the next couple of days while the
system moves over the eastern Caribbean Sea. Kirk is forecast to
become a tropical depression Friday night, and degenerate into a
trough of low pressure by Saturday. Please read the latest NHC
Forecast/Advisory under AWIPS/WMO Headers MIATCMAT2/WTNT22 KNHC
for more details.

Post-Tropical Cyclone Leslie, is located over the central Atlantic
Ocean several hundred miles west of the Azores. Satellite derived
winds indicate that the powerful non-tropical low is producing
storm-force winds that extend several hundred miles from the
surface circulation center. Although, associated shower activity
remains rather limited, Leslie, is still expected to again become
a subtropical storm, or possibly a tropical storm, Friday or
Saturday while it moves west-southwestward at about 10 mph over
the north-central Atlantic. For more information on this system,
see High Seas Forecasts issued by the National Weather Service
under AWIPS header NFDHSFAT1, and WMO header FZNT01 KWBC.

...TROPICAL WAVES...

A tropical wave is approaching the W coast of Africa, and will
likely be added to the 0600 UTC analysis/surface map. A cluster
of moderate to isolated strong convection is related to the wave.

A tropical wave extends from 17N30W to 05N31W moving W at 10 kt.
The wave shows up well in the TPW product. A patch of moisture
with embedded showers is noted near the northern end of the wave
axis.

A tropical wave extends from 17N41W to 05N42W moving W at 10 kt.
The Total Precipitable Water (TPW) imagery shows a maximum E of
the wave axis. Satellite imagery indicates scattered showers
mainly behind the wave axis from 10N-13N between 35W and 40W.

A tropical wave is in the Caribbean Sea along 79W from 20N
southward. A pronounced 700 mb trough in the GFS analysis is
noted with the wave, which also coincides with a north-south
moisture maximum. The wave, along with the monsoon trough, is
helping to induce some shower activity over the SW Caribbean.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Senegal
near 13N16W to 07N20W to 06N29W. The ITCZ extends from 06N32W to
07N40W to 06N50W to near the coast of Guyana at 07N58W. Scattered
moderate to isolated strong convection is from 03N to 08N between
15W and 24W.

...DISCUSSION...

GULF OF MEXICO...

A band of showers with embedded tstms is noted across the Gulf
waters ahead of a stationary front extending from SE Louisiana
to NE Mexico near 25N97W. Recent scatterometer data provide
observations of mainly gentle easterly winds on either side of
the front, forecast to weaken on Fri as high pressure builds
across the Gulf. The high pressure located NE of the region will
support gentle to moderate E to SE winds and seas less than 4 ft
across most of the Gulf waters through Sun.

A surface trough is analyzed over the Yucatan Peninsula. An area
of showers and tstms is seen on the west side of the trough
affecting mainly the W coast of the Yucatan Peninsula and the
eastern part of the Bay of Campeche. A surface trough is forecast
to develop each evening over the Yucatan Peninsula before pushing
offshore into the SW Gulf each night. A surge of moderate to fresh
winds will accompany the trough.

CARIBBEAN SEA...

Tropical Storm Kirk will bring strong winds and heavy rain over
portions of the Lesser Antilles overnight. Please, see Special
Features section for details. A tropical wave is moving across the
Caribbean Sea. See Tropical Wave section for details. Recent
scatterometer data indicate increasing winds of 20-30 kt over the
eastern Caribbean ahead of Kirk, and mainly moderate to fresh
winds across the remainder of the eastern and central Caribbean
while gentle to moderate winds are noted over the NW Caribbean.
As tropical cyclone Kirk weakens over the Caribbean Sea, expect
mainly moderate to fresh winds through early next week. Large
northerly swell associated with Post-Tropical Cyclone Leslie will
affect the tropical Atlantic waters Fri through Sun, building seas
to 10 or 11 ft.

ATLANTIC OCEAN...

A cold front enters the forecast region near 31N33W then continues
SW to 25N40W to 22N57W where it becomes stationary to near 25N70W.
The front is associated with Post-Tropical Cyclone Leslie, which
is centered N of area near 37N45W with a central pressure of 983
mb. This system is moving W at 10 kt. Please, see Special Features
Section for more details.

Large swell generated by Leslie, currently a powerful non-tropical
low pressure system with storm-force winds, is expected to spread
east of 75W by tonight, reaching the Bahamas, the waters N of
Hispaniola and the Atlantic Passages E of la Mona Passage by
early Sat, and the north and central Florida later on Sat.

A ridge extends from a 1022 mb high pressure located near 36N59W
across the western Atlantic, reaching Florida and the Bahamas.
Another ridge dominates the remainder of the Atlantic E of the
aforementioned cold front.

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

$$
GR
This weather bulletin was brought to you by:
www.nashvilleweather.net