216
AXNT20 KNHC 270551
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
151 AM EDT Sat May 27 2017

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.

...TROPICAL WAVES...

A tropical wave is in the eastern Atlc with axis extending from
11N22W to 01N22W, moving W at 15 kt. CIRA LPW imagery shows a
moderate moist environment near the ITCZ with dry air in the
Saharan Air Layer N of 10N. The 700 mb analysis shows a good wave
reflection. Scattered showers are within 120 nm of the wave axis.

A tropical wave is in the central Atlc with axis extending from
10N35W to 01N36W, moving W at 20 kt. CIRA LPW imagery shows a
moderate moist environment near the ITCZ with dry air in the
Saharan Air Layer N of 10N. The 700 mb analysis shows a good wave
reflection along 38W. Scattered moderate convection is E of the
wave axis from 05N-07N between 32W-35W. Scattered showers are
within 120 nm of the remainder of the wave axis.

A tropical wave is in the W Atlc with axis extending from 13N53W
to 05N53W, moving W at 20 kt. This wave shows a well defined
inverted-V surface reflection on satellite imagery. CIRA LPW
imagery shows a moist environment. The 700 mb analysis shows a
good wave reflection along 54W. Scattered moderate convection is
W of the wave axis from 10N-12N between 53W-55W. Scattered
showers are within 120 nm of the remainder of the wave axis.

A tropical wave is just E of the Lesser Antilles with axis
extending from 15N58W to 08N59W, moving W at 15 kt. Unfavorable
wind shear and Saharan dry air across the wave environment is
hindering convection at this time. There is a very pronounced 700
mb wave reflection however along 61W.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough enters the tropical Atlantic near 10N14W and
continues to 06N20W. The ITCZ extends between tropical waves from
06N25W to 05N33W. The ITCZ resumes again near 04N37W and extends
to the coast of South America near 01N50W. Besides the convection
associated with the tropical waves, scattered moderate convection
is from 02N-07N between 15W-21W.

...DISCUSSION...

GULF OF MEXICO...

As of 0300 UTC, a 1019 mb high is located over the NE Gulf of
Mexico near 28N84W. 5-10 kt anticyclonic winds are over the NE
Gulf. 10-20 kt SE surface winds are over the W Gulf. In the upper
levels, a ridge is over the Gulf with axis along 91W. Strong
subsidence is over the Gulf, while upper level moisture is over
Texas. Expect showers to advect into the Bay of Campeche over the
next 24 hours.

CARIBBEAN SEA...

A tropical wave is just E of the Leeward Islands. See above. the
monsoon trough extends over Costa Rica and Panama producing
scattered moderate to strong convection. Further N, scattered
moderate to isolated strong convection is along the coast of
Nicaragua, and inland over Honduras. In the upper levels, a ridge
is over the W Caribbean. An upper level trough is over the E
Caribbean with strong subsidence. Expect over the next 24 hours
for the tropical wave to enter the Caribbean. Also expect
continued convection over the SW Caribbean, and Central America.

...HISPANIOLA...

Saharan dust continue to be reported across the Island and is
observed in satellite enhanced imagery. Water vapor imagery show
strong subsidence over the Island, which is hindering convection
at the moment. However, patches of low level moisture, embedded
in the trade wind flow, could bring some cloudiness and isolated
showers, particularly late Saturday into Sunday.

...ATLANTIC OCEAN...

A cold front in the SW N Atlc long 31N67W to 29N72W. A stationary
front continues to 25N80W. Scattered showers are over portions of
the N Bahamas. A 1025 mb high is centered over the central
Atlantic near 30N50W. A dissipating cold front is over the Canary
Islands with scattered showers. Four tropical waves are over the
tropical Atlantic. Please refer to the Tropical Waves section for
more details. Saharan dry and dust is noted across much of the
Atlantic Ocean between 10N-25N. Of note in the upper levels, a
small upper level low is centered near 23N59W producing upper
level diffluence with scattered showers from 20N-27N between 50W-
55W. Expect over the next 24 hours for the W Atlantic front to
drift E, while a new cold front dips into the central Atlantic
along 32N between 25W-40W with showers.

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

$$
Formosa