[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170918
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Thu Jun 17 2021

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 0600 UTC surface analysis and satellite imagery through
0800 UTC.

...SPECIAL FEATURES...

A broad low pressure area located over the eastern portion of the
Bay of Campeche is producing widespread cloudiness and disorganized
showers and a few thunderstorms. This system will move little
today, and little if any development is expected during that time
due to interaction with land and unfavorable upper-level winds.
However, the low should begin to move northward by this afternoon,
and a tropical or subtropical depression is likely to form by
late tonight or on Fri when the low moves across the western Gulf
of Mexico. Regardless of development, heavy rainfall will
continue over portions of Central America and southern Mexico
during the next few days. Heavy rains should also begin to affect
portions of the northern Gulf Coast on Fri. Please consult
products from your local meteorological service for more
information. This area has a high chance of tropical cyclone
formation in the next 48 hrs. Please refer to the latest Tropical
Weather Outlook issued by the NWS National Hurricane Center at
www.hurricanes.gov for more details on this area.

...TROPICAL WAVES...

An Atlantic tropical wave axis is analyzed near 39W/40W from 19N
southward, moving W at around 20 kt. Scattered moderate convection
is noted from 10N to 13N between 34W and 41W.

An Atlantic tropical wave is approaching the eastern Caribbean
Islands and is analyzed near 49W/60W from 20N southward, moving W
at around 20 kt. Scattered moderate and isolated strong
convection is noted from 12N to 16N between 56W and 62W. Intense
lightning and squalls with very gusty winds have been reported
with this convection at Barbados. Scattered moderate convection is
also noted south of 10N to the north coast of South America
between 55W and 60W.

A Caribbean Sea tropical wave axis is analyzed near 80W/81W from
18N southward across western Panama, moving W at 10 to 15 kt. No
significant convection is directly related to the tropical wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Africa near 11N15W
to 07N21W. Segments of the ITCZ are analyzed from 07N21W to 05N28W
to 07N35W, then resumes near 07N41W to 04N47W to the coast of
French Guiana at 05.5N53W. Scattered moderate and isolated strong
convection is noted within 270 nm south of the ITCZ and monsoon
trough between 19W and 30W, from 07N to 10N between 22W and 25W,
and within 120 nm north of the ITCZ between 43W and 53W.

GULF OF MEXICO...

Refer to the Special Features section above for details on a broad
low pressure area over the Bay of Campeche.

A surface trough is analyzed from 26N90W to the 1008 mb broad
area of low pressure described above near 20.5N92.5W. Aided by
upper-level divergent flow, scattered moderate and isolated strong
convection is occurring across the waters south of 26N and east of
91W, including across the Yucatan Channel and western Straits of
Florida where frequent lightning is noted. A band of scattered
thunderstorms has developed within 60 nm of the coast of Mexico
west of 94W induced by the counter-clockwise flow around the broad
area of low pressure up against the eastern slopes of Mexico.

A stationary front is analyzed from along the Georgia/Florida
border to across the northern Gulf along 29N/30N to southeast
Louisiana. Scattered showers and isolated thunderstorms are near
this front. A broad ridge axis is located between the stationary
from and broad area of low pressure, roughly along 27N/28N. Gentle
to moderate anticyclonic winds are noted north of 26N, moderate to
fresh E-SE winds are noted south of 26N and east of the trough,
with moderate to fresh winds elsewhere. Seas are mainly in the 2-4
ft range, except 4-5 ft in the central Gulf near the trough, and
also in the western Bay of Campeche.

For the forecast, high pressure is forecast to build in across
the basin in the wake of the low pressure area described above
later in the upcoming weekend into early next week.

CARIBBEAN SEA...

A tropical wave is moving across the western Caribbean while
another wave is approaching the Lesser Antilles. Refer to the
Tropical Waves section above for details.

The eastern Pacific Ocean monsoon trough extends across Panama to
NW Colombia near 10N75W. Scattered moderate and isolated strong
convection is noted from 07N to 10N between 75W and 81W. Scattered
showers and thunderstorms are noted in the NW Caribbean including
across the Yucatan Peninsula, Yucatan Channel, and western Cuba
around a broad area of low pressure northwest of the basin in the
SW Gulf of Mexico. Scattered showers and isolated thunderstorms
are occurring in the eastern Caribbean ahead of an approaching
tropical wave.

Fresh to strong NE-E winds were captured by overnight scatterometer
data in the S central Caribbean. Fresh to strong E-SE winds are
pulsing in the NW Caribbean northeast of the Gulf of Honduras.
Mainly moderate to fresh trades prevail elsewhere, except gentle
to moderate in the SW Caribbean south of 11N. Seas of 2 to 4 ft
are in the SW Caribbean south of 11N, with mainly 4-7 ft seas
elsewhere, locally to 8 ft in the S central Caribbean.

For the forecast, a ridge of high pressure north of the basin
combined with lower pressure over Central America and Colombia
will support pulsing fresh to strong trades over the S central
Caribbean and Gulf of Honduras through the upcoming weekend and
into early next week. Moderate to fresh trades will prevail
elsewhere, except light to gentle south of 11N.

ATLANTIC OCEAN...

A pair of tropical waves are moving westward between the west
coast of Africa and the Lesser Antilles. Refer to the Tropical
Waves section above for details.

A diffluent flow aloft continues to support scattered moderate
convection over the Florida Peninsula and western Atlantic mainly
west of 75W. A stationary front extends from 1012 mb low pressure
north of the area near 32N76W to along the Georgia/Florida border.
Scattered showers and thunderstorms are near the front including
across the waters north of 29N and west of 70W. To the east, a
surface ridge dominates the entire Atlantic forecast area anchored
by the Bermuda-Azores High located north of the area. Fresh to
locally strong SW winds are occurring within 180 nm southeast of
the stationary front. Moderate to fresh trades dominate south of
22N, and north of 22N east of 50W. Gentle to moderate trades
prevail elsewhere, except from 18N to 24N between the west coast
of Africa and 25W where fresh to locally strong N-NE winds persist
due to a locally tight pressure gradient. Seas are 7 to 10 ft in
this area. Seas of 5 to 8 ft prevail across the waters elsewhere
south of 22N, with mainly 4 to 7 ft seas across the remainder of
the tropical Atlantic waters.

For the forecast west of 65W, a ridge of high pressure across the
area will retreat eastward today enabling a trough to move
through the northern forecast waters through Fri. High pressure
will then return to the area this weekend into early next week.

$$
Lewitsky
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