[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210514
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 AM EDT Sun Jun 21 2020

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
0500 UTC.

...TROPICAL WAVES...

The axis of a tropical wave is along 25W south of 17N, moving
W near 20 kt. Scattered moderate convection is within 210 nm
of the wave axis from 09N-11.5N. There is no convection
north of 12N due to the presence of dense Saharan dust.

The axis of a tropical wave is along 47W south of 15N, moving
W near 20 kt. Scattered moderate showers and isolated tstorms
are within 270 nm of the wave axis from 03N-11N. Dense Saharan
dust is preventing convection north of 11N.

The tropical wave that was analyzed over the eastern Caribbean
along 64W at 1800 UTC Saturday has been removed from the
analysis.

The tropical wave that was analyzed along 76W at 1800 UTC
Saturday has been moved back east to 70W based on recent
satellite data and upper-air soundings from the Caribbean. The
tropical wave is moving W at 15-20 kt. Isolated moderate
convection is near the wave axis from 15N-17N. TPW imagery
shows moisture extending several hundred miles to the
northeast, enhancing showers near Puerto Rico and the Virgin
Islands.

The axis of a tropical wave is along 85/86W south of 20N,
moving W at 10 kt. Scattered moderate convection is seen
south of 16.5N and west of 82.5W, to include portions of
Nicaragua and eastern Honduras.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 12N17W to 10N22W. The ITCZ is
from 09N27W to 07N45W, then resumes W of a tropical wave from
07N49W to 06N57W. Aside from convection mentioned in the
tropical waves section above, scattered moderate convection is
within 210 nm N of the ITCZ between 30W-44W. Similar convection
is within 180 nm of the ITCZ west of 53W.

GULF OF MEXICO...

A 1017 mb surface high is centered over the NE Gulf of Mexico
near 28N86W, leading to subsidence and relatively dry air over
this region as shown by recent GOES-16 mid-level water vapor
images. Scattered showers and isolated tstorms are seen farther
south over the SE Gulf of Mexico between Key West and the
Yucatan Channel. Isolated showers and tstorms are also noted
over the SE Bay of Campeche. A recent ASCAT pass shows gentle
anticyclonic winds over the NE Gulf associated with the surface
high. Moderate winds prevail over the remainder of the Gulf
waters, except over the eastern Bay of Campeche, where fresh NE
winds are noted.

Surface ridging will dominate the Gulf waters during the next
five days. Gentle to moderate easterly winds and slight seas
are expected through today. Moderate to fresh southerly winds
are forecast over the western Gulf this evening through Thu
night as the pressure gradient tightens between the ridge and
deepening low pressure over Mexico. Strong winds are expected
over the Bay of Campeche at night during this period.

CARIBBEAN SEA...

Two tropical waves are over the Caribbean. See above.

Upper-level diffluence and enhanced mid-level moisture over the
NW Caribbean is leading to scattered showers and tstorms over
Cuba and over the waters between Jamaica and Cuba, as well as
the Yucatan Channel. The east Pacific monsoon trough is
enhancing scattered moderate isolated strong convection over the
SW Caribbean, mainly south of 14N between 75W-84W. An east-west
oriented upper-level trough axis is over the eastern Caribbean.
Isolated showers and tstorms cover portions of the Virgin Islands
and Puerto Rico. The GOES-16 Saharan Air Layer tracking product
shows that a large, westward-moving plume of dense Saharan dust
has now reached the eastern Caribbean Sea. The leading edge of
this plume has reached 63W and is expected to continue westward.
A recent ASCAT pass shows strong trades over the central
Caribbean south of 16N between 69W-77W, with fresh trades
elsewhere south of 18N between 65W-80W. Moderate winds prevail
over the western Caribbean although fresh winds are seen in the
southern Gulf of Honduras.

Fresh to strong trades over the south-central Caribbean will
expand to the north-central and southwest basin this morning
through the middle of the week as high pressure builds over
the western Atlantic. Winds will pulse to near gale force near
the coast of Colombia each night through Wed night with seas
building to near 12 ft with the strongest winds. Fresh to strong
winds are also expected in the Gulf of Honduras from tonight
through Thu night.

ATLANTIC OCEAN...

A weak surface trough extends from 32N69W to 27N72W. A broad
upper-level trough is over the same area. Upper-level
diffluence east of the upper-trough is enhancing scattered
moderate convection from 27N-32N between 65W-70W. Isolated
moderate convection is also seen east of the coast of central
Florida. Farther east, a large upper-level low is centered
near 28N51W. A surface trough extends from 32N49W to 21N58W.
Those two features are causing scattered moderate convection
from 25N-30N between 48W-52W. Isolated showers are elsewhere
from 23N-32N between 45W-53W. A surface high pressure ridge
is over the subtropical eastern Atlantic, with a 1029 mb high
near 33N38W and a 1031 mb high near 35N26W. A large plume of
Saharan dust continues to spread across the tropical waters.
The Saharan dust appears to be particularly dense from
10N-20N between 40W-60W, with a second surge seen between
Africa and 30W.

High pressure will prevail across the offshore waters of the
western Atlantic Ocean through Fri. Fresh to occasionally
strong easterly winds will pulse north of Hispaniola at night
through Thu night.

$$
Hagen
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