[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 142341
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Apr 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
2330 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of Africa over
Guinea near 10N14W to 05N19W, where latest scatterometer data
indicates that it transitions to the ITCZ and continues to the
equator at 28W and to the coast of Brazil near 03S40W. Scattered
moderate convection is within 180 nm south of the trough between
15W-18W and within 120 nm north of the ITCZ and between 20W-23W.

GULF OF MEXICO...

A stationary front is draped in a northeast to southwest fashion
from Apalachicola, Florida southwestward to 2692W and to inland
northeastern Mexico. A pre-frontal trough extends from northeast
Florida southwest to near 27N86W. Abundant atmospheric
instability in the area of this front has helped trigger off
scattered showers and thunderstorms across most of the NE Gulf.
Isolated showers are possible elsewhere near the front. Expect
for the shower and thunderstorm activity to remain active through
Wed as the front begins to push southward as a cold front. A
tight gradient between the front and high pressure building
southward over Texas is allowing for fresh to strong winds to
exist north of this front in the NW Gulf along with wave heights
to 8 ft. Latest Ascat data shows mainly moderate north to
northeast winds elsewhere northwest of the front, with wave
heights of 5-7 ft, while light to gentle southerly winds are
noted south of the front. In the SW Gulf, low pressure of 1012 mb
is identified to be near 21N95W. The low was nicely depicted by
the latest Ascat pass over that part of the Gulf. In addition,
buoy 42055 at 22N94W is reporting light south winds and latest
visible satellite imagery shows low-level clouds rotating
cyclonically near and around this low.

The forecast calls for the above described stationary front to
begin to push southward as a cold front on Wed as high pressure
builds southward in its wake ushering in a drier and cooler air
mass. The front is forecast to become stationary over the south-
central Gulf late Thu and lift back to the north as a warm front
Fri. Fresh to strong northerly winds and building wave heights
are expected in behind the front through Thu. Another cold front
is expected to move over the northern Gulf by Fri night, then
become stationary and lift northward as a warm front by late
Sat. Smoke from agricultural fires in southern Mexico and
Honduras will continue to reduce visibility, at times, over the
south- central Gulf through at least the next few days.

CARIBBEAN SEA...

A surface ridge extends from strong central Atlantic high, that
is well north of the area, southwestward to the northwest
Caribbean. The associated gradient is allowing for generally
gentle to moderate easterly winds across the basin, except in the
south-central Caribbean section and near the coast of Colombia
where pulses of fresh to strong northeast winds will continue
through Thu. Latest buoy and satellite altimeter data passes show
wave heights in the range of 4-6 ft throughout the basin except
for higher wave heights peaking to 8 ft in the Gulf of Honduras
where persistent east winds are in the fresh to locally strong
range.

No significant thunderstorm activity is noted over the Caribbean
at this time as very dry aloft maintains rather stable and dry
conditions throughout. The only exception is that of quick
moving isolated showers as observed on regional radar over the
Leeward and Virgin Islands as well as over the interior of
Puerto Rico and its surrounding waters.

The forecast calls for the gradient associated with the central
Atlantic ridge to maintain fresh to strong winds near and along
the coast of Colombia and Honduras through Thu. Winds and seas
over much of the basin will diminish through the end of the
week as the Atlantic weakens and shifts eastward. Smoke from
inland agricultural fires, as noted in the GOES-R visible
imagery, may limit visibility, at times, off the Yucatan
Peninsula and the offshore waters of Belize and Honduras possibly
into Fri.

ATLANTIC OCEAN...

The 18Z analysis has a surface ridge extending from a 1031 mb
central Atlantic high center, that is located well north of the
area near 37N48W, southwestward from this high to Bermuda, then
to the northwestern Bahamas and to South Florida. A stationary
front is draped northeast to southwest inland over inland
Georgia. A series of upper-level shortwave troughs are quickly
moving from west to east over the southeastern U.S. while at
the same time plenty of upper-level moisture, as noted in water
vapor imagery, is streaming eastward via a strong jet stream
remains evident over and near this boundary. These ingredients
have come together, with the end result being the development of
scattered shower and isolated thunderstorm activity over the
northwest part of the area north of 29N and west of 70W. Some of
this activity may produce gusty winds and rough seas as it is
expected to last through at least Wed. Latest satellite data
indicates the highest frequency of lightning to be north of 30N
and between 74W-78W. A recent Ascat pass revealed moderate to
fresh southerly winds north of about 27N and west of 74W, where
wave heights are 4-6 ft.

Farther east, a cold front is along a position from near 32N34W
to 27N41W, where it becomes stationary to 22N57W. A sharp upper-
level trough is over the cold/stationary front. Upper-level
divergence east of this trough is helping to support areas of
rain with possible embedded scattered showers along the cold
front, east to a line from 32N26N to near 27N39W and within 60 nm
north and of the cold and stationary fronts. Isolated showers
moving quickly westward in fast east flow are elsewhere near the
stationary front. The gradient between this boundary and the
strong high pressure center north of the area is resulting in
fresh to strong northeast winds along with wave heights in the
range of 8-10 ft over an area that is bounded from 27N to 32N and
between 42W-55W. These conditions are forecast to improve by
early Wed as the front weakens.

The forecast calls for the aforementioned stationary front to
begin to push southeastward as a cold front on Wed, reach a
position from near 32N71W to South Florida by early Thu, then
from near 28N65W to the Straits of Florida by Thu night. The
front is then expected to become stationary near 25N on Fri, and
lift back to the north as a warm front while weakening through
Fri night. Fresh to strong northerly winds are expected behind
this front on Thu. A surface ridge will develop northeast of the
warm front on Fri near 33N. Models suggest that the ridge will
be forced southward this weekend in response to a cold front that
will move off the southeastern U.S. coast this weekend and
across the far northern waters through late Sun. Scattered
showers and isolated thunderstorms are possible with this front.

$$
Aguirre
This weather bulletin was brought to you by:
www.nashvilleweather.net