AXNT20 KNHC 201734
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Tue Apr 20 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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.
Based on 1200 UTC surface analysis and satellite imagery through
The monsoon trough passes through the coastal sections of Sierra
Leone near 08N13W, 03N20W, to 01N25W. The ITCZ continues from
01N25W, to the Equator along 35W, and continuing along the
Equator at 45W, to 04N50W. Precipitation: widely scattered
moderate to isolated strong in clusters is from 10N southward
from 56W eastward.
GULF OF MEXICO...
A cold front passes through Lake Okeechobee in Florida, to
25N85W in the Gulf of Mexico. The front becomes stationary at
25N85W, and it continues to a 1012 mb low pressure center that
is near 21N95W. The stationary front continues from the 1012 mb
low pressure center, to 19N94W, and to 18N96W. A surface trough
runs north-to-south, in the Yucatan Peninsula. Precipitation:
scattered to numerous strong is within 180 nm to the south of
the frontal boundary between 81W and 87W. Widely scattered
moderate to isolated strong is from 25N southward from 87W
eastward. Isolated moderate is elsewhere from 28N southward from
88W eastward. It is possible that strong gusty winds and rough
seas may be in some of the areas of the comparatively heavier
and more intense precipitation.
A cold front extends from Fort Myers, Florida, to 24N90W, where
it transitions to a stationary front to the Bay of Campeche. The
cold front will be nudged southward, to the far southeastern
Gulf of Mexico on Wednesday, and to the lower Straits of Florida
on Wednesday night. High pressure in its wake, will shift
eastward through Saturday night, as a cold front reaches eastern
Texas. Fresh to strong southerly winds will develop in the NW
and in the central Gulf of Mexico, from late Friday through
Saturdat. Scattered rainshowers and thunderstorms will be
focused along and near the cold front today and tonight. Some of
this activity may produce strong gusty winds and rough seas.
Water vapor imagery and the GFS model for 250 mb show an
anticyclonic circulation center that is in the SE coastal
sections of Nicaragua. Upper level anticyclonic wind flow covers
the Caribbean Sea from 70W westward. Upper level cyclonic wind
flow covers the Caribbean Sea from 70W eastward, with an
Atlantic Ocean trough.
The GFS model for 700 mb shows: Broad cyclonic wind flow covers
the SW corner of the Caribbean Sea, from 15N southward from 72W
westward. Precipitation: scattered to numerous strong is in SE
Nicaragua. Widely scattered moderate to isolated strong is in a
line from central Panama toward SE Nicaragua.
The monsoon trough is along 11N73W in northern Colombia, through
the border of Colombia and Panama, beyond 07N80W and 07N86W,
into the eastern Pacific Ocean. Precipitation: scattered to
numerous strong is in SE Nicaragua. Widely scattered moderate to
isolated strong is in a line from central Panama toward SE
Broken to overcast low level clouds, and isolated moderate
rainshowers, cover the rest of the Caribbean Sea. The clouds and
isolated moderate precipitation are moving with the
surface-to-low level wind flow.
Fresh to strong trade winds in the central Caribbean Sea will
diminish by late in the week, as high pressure in the central
Atlantic Ocean shifts eastward, except near the coast
of Colombia where these winds will persist through the week.
A first cold front passes through 32N68W, to Lake Okeechobee in
Florida. A second cold front passes through 32N73W to 30N80W,
about 130 nm to 180 nm to the NW of the first cold front.
Precipitation: widely scattered to scattered moderate, and
isolated to widely scattered strong, are to the northwest of the
line that passes through 32N50W, to 26N60W, and to 23N80W. It is
possible that strong gusty winds and rough seas may be in some
of the areas of the comparatively heavier and more intense
A surface ridge extends from a 1023 mb high pressure center that
is near 33N21W, to a second 1023 mb high pressure center that is
near 28N33W, to a 1024 mb high pressure center that is near
27N43W, 24N69W, across the Bahamas and Cuba, to 20N82W in the NW
corner of the Caribbean Sea. Surface anticyclonic wind flow
covers the Atlantic Ocean, away from the 32N68W-to-Lake
Okeechobee in Florida cold front, eastward and southeastward.
The current weak cold front, that extends from 31N70W to West
Palm Beach, Florida will stall E of 75W near 30N tonight, while
W of 75W it will continue slowly southward. By early Wednesday,
the stationary front will have move northward as a warm front,
while the cold front will extend from NE of the Bahamas to the
Florida Keys, and from near 31N69W to the central Bahamas and to
west central Cuba by late Wednesday night, as another cold front
moves into the NW waters. By late Thursday, both fronts will be
weakening NE of the Bahamas, as high pressure builds into the
area. The high pressure will shift eastward through Saturday
night, as a stronger cold front approaches the southeastern
U.S.A. coast. The stronger cold front will be preceded by fresh
to strong southerly winds in the far NW waters, along with
possible scattered showers and thunderstorms.