[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091731 AAA
TWDAT

Tropical Weather Discussion...UPDATED
NWS National Hurricane Center Miami FL
1805 UTC Fri Jun 9 2023

Updated to include new observed rainfall amounts from the Bahamas

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 1200 UTC surface analysis and satellite imagery through
1700 UTC.

...SPECIAL FEATURES...

Excessive Rainfall in Eastern and Central Cuba and the Central
Bahamas: An upper level trough located over the eastern Gulf of
Mexico with SW flow extending down to the surface is transporting
a large amount of moisture northward from the deep tropics,
creating an atmospheric river over Cuba and the Central Bahamas.
Over the past 24 hours, Las Mercedes in Granma, Cuba reported 14
inches (360 mm) of rainfall. Additional reports show 24 hour
rainfall amounts ranging from 8-12 inches (200-300 mm) elsewhere
in Granma, Santiago de Cuba, and Camaguey. In the Bahamas, 8
inches (200 mm) was reported on Exuma and 4 inches (100 mm) was
reported on Long Island over the past 24 hours. Persistent
convection in eastern and central Cuba and the central Bahamas is
forecast to produce another 4-6 inches (100-150 mm) of rainfall
over the next 48 hours, with isolated higher amounts to 12 inches
(300 mm) possible. Heavy rainfall may cause flooding and
mudslides, especially in the mountainous areas of eastern and
central Cuba. Please refer to the latest forecast from your
national meteorological service for more information.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 18W from 11N southward,
moving W at 10-15 kt. No significant convection is noted with
this wave at this time.

An Atlantic Ocean tropical wave is along 40W from 12N southward,
moving W from 10-15 kt. No significant convection is noted with
this wave at this time.

An Atlantic Ocean tropical wave is along 61W from 12N southward
over Guyana, Venezuela, and far northern Brazil, moving W at
10-15 kt. No significant convection is noted with this wave at
this time.

A Caribbean Sea tropical wave is along 79W from 12N southward,
moving W at 10-15 kt. No significant convection is noted in the SW
Caribbean at this time. The moisture associated with this tropical
wave is likely contributing to the moisture transported within
the Atmospheric River to the north.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Sierra Leone near
11N15W to 07N22W. The ITCZ continues from 07N22W to 06N39W and
then continues west of a tropical wave 07N41W to 07N54W. Scattered
moderate convection is from 03N to 08N between 20W and 37W.
Showers are elsewhere in the vicinity of the boundaries.

GULF OF MEXICO...

Quiescent conditions continue in the Gulf of Mexico, with light
to gentle variable winds and seas of 1-2 ft. Isolated showers and
tstorms are off the coast of Louisiana in the north-central Gulf,
ahead of a weak stationary front positioned inland.

For the forecast, light to gentle winds can be expected through
Sat morning. As weak low pressure along a frontal boundary
develops over Texas on Sat, moderate to locally fresh return flow
will prevail at times over the western Gulf through the weekend
and into early next week.

CARIBBEAN SEA...

Please read the SPECIAL FEATURES section for information on
EXCESSIVE RAINFALL for Eastern and Central Cuba.

Moderate to fresh trades prevail in the eastern and central
Caribbean, with 4-7 ft seas. Light and variable winds are in the
western Caribbean, with 2-4 ft seas. Scattered moderate isolated
strong convection producing excessive rainfall over Cuba extends
over the waters north of 18N between 77W and 80W, between Jamaica
and Cuba. Isolated showers and tstorms are noted in the SW
Caribbean near the tropical wave.

For the forecast, high pressure over the central Atlantic
extending across the area today will maintain fresh to strong E to
SE trade winds across the eastern and central Caribbean. Winds
and seas will diminish only slightly across the basin through the
weekend. A return to a more typical easterly trade wind regime is
expected early next week with fresh to strong trades in the south-
central Caribbean and Gulf of Honduras. Enhanced thunderstorms
will continue between eastern Cuba and Jamaica through at least
tonight, due to the influences of an upper- level trough just NW
of the area.

ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for information on
EXCESSIVE RAINFALL in the Central Bahamas.

Scattered moderate convection, associated with the excessive
rainfall, is currently from the coast of Cuba north to 26N between
73W to 78W. Moderate to fresh SW winds are co-located and NE of
the convection in the W Atlantic waters, with seas of 6-8 ft.
Elsewhere, diffuse subtropical high pressure centers exist across
the waters, providing light to gentle anticyclonic flow across the
basin. Seas are 3-6 ft across the tropical Atlantic as a result of
the weak winds. Three weak surface troughs, with some isolated
showers, are analyzed in the central Atlantic.

For the forecast west of 55W, high pressure extending from the
central Atlantic will create a tight pressure gradient with low
pressure off the SE US coast. This will maintain fresh to strong
SW winds over the SW Atlantic, in between the Bahamas and Bermuda,
through Sat morning. As the low pressure off the SE US coast
moves away well to the north of the area, gentle to moderate winds
will prevail over the area Sat afternoon through the weekend and
into early next week. Enhanced thunderstorms will continue over
portions of the western Atlantic, including the Bahamas, through
Sat.

$$
Mahoney
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