[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192234
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri May 20 2022

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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2140 UTC.

...SPECIAL FEATURES...

Global models continue to suggest a Central American Gyre (CAG)
will form across Central America and the adjacent southwest
Caribbean by Fri, and then gradually shift west to northwest
across Central America through early next week. CAGs tends to
enhance the strength of SW monsoon flow, and lift the monsoon
trough well north of its typical position. This will increase
convergent surface winds and advect abundant tropical moisture
northward, triggering widespread strong convection over Central
America. Expect heavy rainfall commencing across Panama and Costa
Rica today, then spreading to parts of Costa Rica, Nicaragua,
Guatemala and Honduras. Extreme rainfall is possible across the
Pacific coasts of these countries, and also over southern Honduras
and northeast Nicaragua. This will increase the potential for
flash flooding and mudslides, especially across mountainous
terrain. Please refer to products issued by your local weather
service for more information.

...TROPICAL WAVES...

A tropical wave is in the central Atlantic with axis along 40W-
41W, from 03N to 10N along 39W, moving west at 10-15 kt.
Associated convection has decreased due to SW upper level wind
shear. Widely scattered moderate convection is from 04.5N to 07N
between 38W and 41W.

A tropical wave is in the western Caribbean with axis S of 18N
along 85W, moving west at 10-15 kt. Scattered moderate to strong
convection is occurring mostly behind the wave, S of 16N between
76W and 85W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the African coast near 07N11.5W
to 06N21W. The ITCZ continues from 06N21W to 03N39W, then resumes
west of the tropical wave from 01.5N41W to 01N52W. Scattered
moderate to strong convection is noted from 05N to 07N between 11W
and 16W. Scattered moderate isolated strong convection is noted
from 00N to 07N between 45W and 51W.

...GULF OF MEXICO...

Surface ridging extends from the W Atlantic to central Florida
and then across the eastern Gulf to 91W. A low pressure trough
extends southward across northeast Mexico. This pattern is
supporting moderate to fresh return flow and seas of 3-5 ft W of
90W and light to gentle variable winds with seas to 3 ft E of 90W.
Fair skies dominate most of the Gulf, except for scattered
thunderstorms across western Cuba lifting northward across
portions of the Straits of Florida.

For the forecast, high pressure over the northeast Gulf will
shift eastward through Fri, as low pressure develops south of the
area over Central America. This pattern will allow an area of
moderate to fresh southeast winds over the western Gulf to expand
eastward across the Gulf by late Fri. Winds and seas will then
diminish slightly across most of the basin Sun through early next
week as the pressure gradient relaxes, leaving only pulses of
fresh to occasionally strong winds at night off the northern and
western Yucatan Peninsula.

...CARIBBEAN SEA...

Please see the Special Features section for information on a
potential heavy rainfall event.

Surface ridging over the western Atlantic along 27N-28N is
supporting moderate to fresh trade winds across the east and
central Caribbean, except for fresh to strong winds in the south-
central Caribbean. Seas in these regions are in the 5-8 ft range.
Gentle to moderate SE winds are elsewhere with seas to 4 ft.
Microwave satellite imagery show abundant moist air across the
western Caribbean, which coincides with a region of middle to
upper level divergent flow. These atmospheric conditions along
with the influence of the E Pacific monsoon trough and a tropical
wave along 85W are combining to support heavy showers and tstms
over portions of the SW Caribbean south of 16N. For further
information, see the tropical waves section.

For the forecast, winds and seas across the basin will increase
tonight into the weekend as the ridge strengthens and broad lower
pressure forms over Central America. The strongest winds and
highest seas are expected to be over parts of the northwestern and
south-central Caribbean during this period. Looking ahead, winds
and seas will start to diminish over the eastern and central
Caribbean early next week as the ridge to the north and the lower
pressure over Central America weakens.

...ATLANTIC OCEAN...

A weak surface ridge covers the SW N Atlantic waters, extending
along 27N-28N, which is supporting mainly light to gentle
anticyclonic winds in that region, except for locally moderate to
fresh winds in the Great Bahama Bank and N of Hispaniola and
Puerto Rico. Seas in this region are in the 2-4 ft range except
lower in the protected waters of the Bahamas. The remaining
subtropical Atlantic waters are under the influence of a ridge
anchored by a 1021 mb high near 28N42W. Morning scatterometer data
showed moderate to locally fresh tradewinds south of 20N and west
of 35W, with seas of 5 to 7 ft. North of 20N, light to gentle
variable winds prevail, with seas 3 to 5 ft.

For the forecast west of 55W, the surface ridge will lift north
to 30N through Fri and strengthen. This pattern will support
mainly gentle to moderate breezes across the region through early
next week, except for moderate to fresh winds north of Hispaniola
starting late Fri.

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