[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041802
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT THU AUG 04 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 analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...SPECIAL FEATURES...

Tropical Storm Earl is well inland over northern Guatemala near
17.3N 90.2W moving W at 10 kt. Estimated minimum central
pressure has risen to 994 mb. Maximum sustained wind speed has
decreased to 40 kt with gusts to 50 kt. Latest satellite imagery
shows scattered moderate to isolated strong convection in bands
over the western Gulf of Honduras. Scattered moderate convection
is over much of Guatemala, and in narrow bands just north of
northeast Honduras. Earl is forecast to weaken further to a
tropical depression by this evening as tracks further inland.
Earl is expected to produce total rain accumulations of 8 to 12
inches over portions of Belize, Honduras, Guatemala, and Mexican
states of Campeche, Chiapas, Quintana Roo, Tabasco and Veracruz
through Friday morning. Isolated maximum amounts of 18 inches
are possible in Belize, northern Guatemala and the central part
of the Mexican state of Chiapas. These rains could result in
life-threatening flash floods and mudslides. Please see latest
NHC Intermediate Public Advisory under AWIPS/WMO headers
MIATCPAT5/WTNT35 KNHC and the full forecast/advisory under
AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details.

...TROPICAL WAVES...

Tropical wave axis in the central Tropical Atlantic extends from
20N45W to 14N46W to 07N45W, and is estimated to be moving west
at 20 kt over the past 24 hours. The wave coincides with a 700
mb trough as depicted in the global models. It remains embedded
within a low-amplitude surge of moisture with Saharan dry air
and dust evident just northwest through north of the wave, as
seen on the SSMI Total Precipitable Water Imagery. Scattered
moderate convection is confined near the southern extent of the
wave axis from 08N-11N between 45W-50W.

Tropical wave axis in the central Tropical Atlantic extends from
21N57W to 14N58W to 09N58W...and is estimated to be moving west
around 20 to 25 kt over the past 24 hours. The wave coincides
with a 700 mb trough as depicted in the global models and is
embedded within a deep surge of moisture as seen on the SSMI
Total Precipitable Water Imagery. Latest satellite imagery shows
quite an impressive flare up of scattered moderate to strong
convection from 17N to 21N between the wave axis and the
northern Leeward Islands. Upper level diffluence present over
the northern portion of the wave is helping to sustain the
aforementioned convective activity. This wave is forecast to
move into the eastern Caribbean Sea tonight, then move through
the central Caribbean Friday and the western Caribbean Saturday
before moving west of the sea on Sun. Gusty winds can be
expected with the wave as it quickly tracks across the Caribbean
basin.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough axis extends across Africa into the eastern
Tropical Atlantic near 11N16W to 10N29W to 08N37W. The ITCZ
begins briefly at 08N37W and ends west of the southern portion
of a tropical wave axis near 08N45W. It continues at 09N46W to
just west of another tropical wave axis at 09N58W, then a short
segment resumes just west of same wave, and continues to coast
of South America near 09N62W. Besides the convection described
above in the tropical wave section, scattered moderate to strong
convection is seen 30 nm of line from 09N14W to 09N20W.
Scattered moderate to isolated strong convection is within
180 nm south of the trough axis between 22W and 29W. Scattered
moderate convection is within 120 nm south of the axis between
29W and 31W.

...DISCUSSION...

GULF OF MEXICO...

A surface ridge axis extends from the Atlantic to the NE Gulf of
Mexico along 28N. A trough extends from northeast Florida
southwest to near 28N88W. The combination of mid-level energy,
and already available instability across the northeast Gulf has
resulted in clusters of scattered moderate to isolated strong
convection from 26N to 31N east of 88W. Widely scattered showers
and isolated thunderstorms are noted from 26N to 31N between 88W
and 90W. An upper anticyclone is noted on water vapor imagery to
be centered over the far northern Gulf near 30N89W. The
northeast flow east of the anticyclone is spreading high cirrus
clouds from the convection southwest to near 25N89W. In the far
southern portion of the Gulf, the leading edge of precipitation
consisting of scattered moderate convection from Tropical Storm
Earl extends northward to the Yucatan Channel and the eastern
Bay of Campeche. This activity is forecast to gradually spread
westward to the far southwest Gulf through Friday night. Strong
to near gale force east winds are in the eastern Bay of Campeche
from the tight pressure gradient associated with Tropical Storm
Earl. These winds are forecast to decrease late Friday into
Saturday.

CARIBBEAN SEA...

Tropical Storm Earl is inland and weakening over northern
Guatemala early this afternoon. See Special Features section
above. Water vapor imagery shows that a large envelop of very
deep moisture trailing behind Earl, and covers the entire
western Caribbean, and much of the central portion of the basin.
This moisture is within a broad area of low pressure as noted in
the 12 UTC surface analysis. Scattered moderate convection, some
in clusters, is seen within these areas. Scattered moderate to
isolated strong convection is just entering the far northeast
portion of the sea in association with the approaching tropical
wave described above. The pressure gradient throughout supports
15 to 25 kt trade winds, with the high end of this range
confined to the north-central and northwest portions of the sea.

...HISPANIOLA...

An upper level low is just north of Hispaniola, however limited
moisture in the surrounding environment is only allowing for
isolated showers and possible weak isolated thunderstorms to
exist near its north coast. The upper low is forecast to move
west and weaken over the next 48 hours. There is some
opportunity for scattered showers and isolated thunderstorms to
over the island this afternoon with ongoing daytime heating.

ATLANTIC OCEAN...

A cold front is along west of 75W while shortwave energy is
moving eastward over the southeastern U.S. Scattered moderate
convection is observed within 120 nm s of the front. This
activity is forecast to persist through Friday. a large upper
anticyclone is seen over the central Atlantic near24N50W. The
flow pattern between the anticyclone and the upper low just
north of Hispaniola near 22N71W is keeping a very moist upper
flow between the tropical wave along 21N57W to 09N58W and the
low. Upper level moisture associated with convection from the
wave is spreading north to near 26N between 56W and 63W in the
form of broken cirrus clouds. Elsewhere...dry air aloft is
keeping stable conditions with only possible isolated showers
and thunderstorms west of 56W. The convection associated with
the tropical waves will translate westward across the far
southern portions of the basin during the next 48 hours.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Aguirre
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