Tropical Weather Discussion
Issued by NWS
AXNT20 KNHC 240001
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MAY 23 2016
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
Based on 1800 UTC surface analysis and satellite imagery through
New tropical wave was analyzed over Africa extending from the
Ivory Coast to Burkina and estimated to be moving west at 10-15
kt. Easterly wave diagnostics and well defined 850 mb relative vorticity
in Hovmoller time sections aided in the placement of this feature.
Tropical wave extends from 01N28W to 09N29W moving west at 15-20
kt. The wave was relocated further west based on a combination of
easterly wave diagnostics and NWP hovmoller time sections.
Scattered moderate convection was occurring within 180 nm west of
the wave axis from 04N to 07N.
Tropical wave extends from 02N47W to 09N44W moving west at 15 kt.
The wave coincides with a subtle mid-level 700 mb trough and
associated relative vorticity aloft in the vicinity of the wave
axis near 07N. Scattered moderate convection was occurring from
is from 07N to 09N between 39W and 43W.
Tropical wave extends from 11N74W to 15N73W moving west at 15-20
kt. This was relocated further west based on a combination
of easterly wave diagnostics and moisture patterns in total precipitable water
imagery. No significant convection was associated with the wave.
The Monsoon Trough extends from the African coast of Sierra Leone
near 08N13W to 05N20W. The Intertropical Convergence Zone axis
extends from 05N20W to 03N35W to 04N45W to 04N52W. No significant
convection was associated with the ITCZ/monsoon trough.
GULF OF MEXICO...
A very sharp late-season middle-to upper level trough extends from a
large mid-to upper level low off the Virginia capes southward over the
SW N Atlantic, Florida into the northeastern Gulf of Mexico. Deep layered
subsidence was wrapping around the base of the trough over the Gulf
and Florida. The trough was digging southward with dry air pressing
southward down the Florida peninsula. This trough provided support for
a stationary front which extended from near Fort Myers to near 27N86W,
where it becomes diffuse to near 28.5N90W. Isolated showers and tstms are
occurring south of the front across the extreme southeast gulf waters and
extended over interior south Florida and the Florida Straits. The remainder of the
Gulf is under the influence of NW flow aloft and gentle to moderate east-to
southeast winds on the southwestern periphery of a ridge anchored by a
1015 mb high centered near Pensacola, Florida. The frontal boundary is
expected to dissipate over Florida and the SE gulf by late tonight. However, east
southeast flow is expected to continue through Wed with winds increasing
over the western gulf by late Wed.
The surface pressure gradient across the Caribbean Sea remains
relatively strong due to a ridge anchored across the central
Atlantic and lower pressure noted across northern South America. The
gradient is resulting in mostly fresh to strong trades across
the basin with the strongest winds occurring across the south-
central and SE portion of the basin. Earlier 1346 and 1438 UTC
ASCAT passes showed areas of 20-25 kt winds over the Caribbean
from the north coast of South America to 16N east of 72W. As the ridge
remains nearly stationary and strengthens slightly...the resulting
gradient is expected to maintain the area of fresh to strong
trades across the eastern and central Caribbean primarily E of
76W through Wed. Otherwise...fairly tranquil conditions
prevail across the remainder of the Caribbean with only a few
isolated showers and tstms occurring S of 11N across the
adjacent coastal waters of Costa Rica...Panama...and Colombia.
The presence of somewhat diffluent southwesterly flow aloft to the east
of an upper level trough axis extending from western Cuba to to near the coast
of Nicaragua combined with a fairly moist environment overall has led
to scattered showers and thunderstorms the afternoon and evening over the
interior portions of Haiti and the Dominican Republic. The 12Z rawindsonde from
Santo Domingo indicated moisture up to about 550 mb with precipitable water
values of 2.11 inches. Very little change is expected in the general pattern over the
next 24 hours.
A large middle-to upper level low centered along the Virginia capes with
troughing dipping southward over much of the SW North Atlantic. The trough
supports a 1008 mb low centered off the Delmarva near 37N72W with the
associated cold front extending S-SW through 32N71W to the east coast
of Florida near Palm Beach. Multilayered clouds with embedded showers and
isolated tstms are occurring within 300 nm E-SE of the front with a more
concentrated area of tstms farther east from 25N to 28N between 64W and
67W within an area of strong middle-to upper level diffluence. Farther east...a
surface ridge influences much of the central and eastern Atlc anchored by a
weakening 1025mb high centered near 28N46W. Just north of this high
center...a cold front enters the discussion area near 32N22W and extends SW
to 28N38W then becomes a diffuse stationary front to 32N51W. Broken to
overcast low clouds with possible isolated showers are within 90 nm either
side of the front. To the north of the front...a 1031 mb high is centered near 35N44W
that will move southeast and become the dominant feature across the central Atlc
as the front dissipates by early Tue.
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