[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150004
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM Thu May 14 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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURES...

An increasing area of cloudiness along with numerous showers and
thunderstorms is over the Straits of Florida and western
Atlantic waters south of 27N and west of 70W, including the
Bahamas and vicinity waters. In addition, a very tight pressure
gradient between strong high pressure ridging centered off the
eastern U.S. seaboard and a surface trough that extends from
central Bahamas westward to the Straits of Florida is producing
strong northeast to east winds with frequent gusts to gale force
over these waters as is presently being noted in both buoy and
ship observations. These winds are forecast to continue into Fri
afternoon. As a result, a gale warning for frequent gusts is in
effect for the waters south of 27N and west of 74W. Please read
the latest High Seas Forecast https://www.nhc.noaa.gov/text/
MIAHSFAT2.shtml for more details.

Environmental conditions are expected to become conducive for
development for the aforementioned area of cloudiness and
shower and thunderstorm activity. This system is likely to
become a tropical or subtropical storm by late Fri or Sat when
it is located near the northwestern Bahamas. The system is then
forecast to move generally northeastward over the western
Atlantic early next week. Regardless of development, the
disturbance has the potential to bring heavy rainfall to
portions of the Florida Keys, southeast Florida, and the Bahamas
through Saturday. Tropical-storm-force wind gusts are also
possible in the Florida Keys, southeast Florida, and the Bahamas
during the next day or two. Hazardous marine conditions are also
expected along the Florida east coast and in the Bahamas where
Gale Warnings are in effect. The system now has a high chance of
becoming a tropical or subtropical storm during the next 48
hours. Please refer to the latest NHC Tropical Weather Outlook at
www.hurricanes.gov for more details and also see products from
your local weather office.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the coastal sections of
Guinea-Bissau near 12N16W to 08N20W, where afternoon
scatterometer data indicates that it transitions to the ITCZ and
continues to 04N30W to 02N40W and to 00N49W. Scattered moderate
convection is within 120 nm north of the ITCZ between 34W-38W and
between 40W-46W. Similar activity is within 60 nm south of the
ITCZ between 39W-42W.

GULF OF MEXICO...

Broad upper level westerly wind flow is present across the
Gulf. Within this flow pattern, a pair of embedded shortwave
troughs advancing eastward are noted. One is over the north-
central Gulf, the other is over the southeastern Gulf. At the
surface, a trough is oriented east to west across the
Straits of Florida, while high pressure ridging extends from
the western Atlantic across the basin. Scattered showers and
isolated thunderstorms are over the north-central Gulf waters
north of 29N and between 90W-94W, while isolated showers
occurring in the outer western fringes of the Special Features
system are over the far southeastern Gulf.

Mainly moderate to fresh east to southeast winds are over the
Gulf, except for stronger winds of fresh to strong speeds, over
the southeastern Gulf waters south of 27N and east of 84W based
the latest Ascat data pass and buoy data. Wave heights are in the
range of 4-7 ft, except for higher heights of up to 8 ft over
the waters south of 27N and east of 84W.

As for the forecast, the trough over the Straits of Florida will
change little tonight then begin to lift northward Fri. The
gradient between the high pressure ridge and trough will
maintain little change to winds over the eastern and central Gulf
through most of Fri. Little change with winds is expected
elsewhere through the upcoming weekend. Low pressure may develop
near Louisiana on Sun and pull a weak cold front across the
northern Gulf early next week.

CARIBBEAN SEA...

A trough is over the northwestern Caribbean along a position from
22N82W to 18N87W. No significant weather is associated to this
trough. Scattered showers and thunderstorms are over the interior
of Cuba and moving in a general northeastward direction. Similar
activity is over the interior of northern Haiti and the western
part of the Dominican Republic. Isolated showers and
thunderstorms are seen over the southwestern Caribbean south
of 13N and west of 80W. Brief passing isolated showers are
possible mainly north of 14N, where low-level cloud streamers
are present.

Moderate to fresh trade winds are over sea, with the exception
of the south-central section where fresh to strong trade winds
are present. Wave heights are in the range of about 3-6 ft,
except in the south-central section of the sea where higher wave
heights of up to 8 ft are due to the persistence of the fresh to
strong trade winds there.

As for the forecast, high pressure will remain north of the
region tonight, then shift eastward and weaken Fri into this
weekend. Fresh to strong trades will prevail in the south-central
Caribbean into early next week.

ATLANTIC OCEAN...

Please refer above to the Special Features section for details
about a system that has potential to become a tropical or
subtropical storm by late Fri or Sat.

A cold front extends from near 32N50W southwestward to 29N56W,
where it transitions to a stationary front to 26N62W and to
25N70W, where it becomes a trough across the central Bahamas and
to the Straits of Florida. The tight gradient between the strong
high pressure over the western Atlantic and the trough has
induced strong northeast to east winds with frequent gusts to
gale force over a good portion of the western half of the area.
For details refer above under the Special Features section. Areas
of rain along with numerous showers and scattered thunderstorms
are increasing in coverage south of 28N and west of 70W. To the
southeast of the stationary front, a weak 1018 mb low is analyzed
near 26N57W, with a trough extending northeastward to 28N55W and
southwestward to near 22N59W. No significant convection is
associated with this feature. Scattered showers are seen from 25N
to 28N and between 53W and the low and trough. High pressure
dominates the remainder of the Atlantic anchored by a 1027 mb
high center analyzed just north of the discussion area at
33N31W.

As for the forecast, the trough over the central Bahamas and
Straits of Florida will lift northward through Fri. See Special
Features section for tropical or subtropical potential of a
system near the NW Bahamas late Fri or Sat. This system is likely
to significantly impact winds and wave heights over the western
half of the area into early next week.

$$
Aguirre
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