[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101732
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
132 PM EDT SAT SEP 10 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
1700 UTC.

...SPECIAL FEATURES...
Tropical wave extends from 13N45W to 21N44W moving W at 15 kt. A
1010 mb low is centered at the southern extent of the wave axis
that remains embedded within the Monsoon Trough as part of a
broad monsoonal gyre. Unorganized widely scattered moderate
convection is from 08N-20N between 37W-50W. In addition...
developing near gale to gale force winds are expected within
24-36 hours as the low moves W-NW and generates a strengthened
pressure gradient against surface ridging across the central Atlc
to the north. Strongest winds are anticipated within the northern
semicircle through Sunday morning as the low continues to organize
and the overall environment becomes favorable for tropical cyclone
development by early next week. See latest NWS High Seas Forecast
under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details.

...TROPICAL WAVES...
Tropical wave extends from 12N17W to 20N17W moving W at 10-15 kt.
The wave coincides with broad 700 mb troughing between 10W-23W and
a maximum in 850 mb relative vorticity along the wave axis focused
near 17N. To the SW of the wave...another global model indicated
850 mb relative vorticity maximum is noted...likely the southern
vortex of the wave...by a 1014 mb low centered along the Monsoon
Trough near 10N20W. Most convection is associated with this low as
scattered moderate convection is from 07N-12N between 14W-20W...
and from 09N-14N between 19W-28W.

Tropical wave extends from 08N79W to 19N78W moving W at 15 kt.
The wave coincides with broad 700 mb troughing between 75W-82W and
remains embedded within the cyclonic wind flow associated with the
semi-permanent Colombian low. Scattered moderate and isolated
strong convection is from 09N-12N between 75W-84W.

Tropical wave extends from 11N94W to 21N92W moving W at 10-15 kt.
Much of this wave influences the East Pacific region south of the
Gulf of Tehuantepec...however the northern portion of the wave
continues to weaken across the SW Gulf of Mexico. The most active
convection is occurring in association with a fractured portion of
the wave analyzed as a surface trough across the central Gulf of
Mexico from 22N91W to 27N89W that continues to fall under the
influence of an upper to middle level trough over east Texas and
the far western Gulf of Mexico. Scattered moderate convection is
from 25N-29N between 87W-91W.

...ITCZ/MONSOON TROUGH...
The Monsoon Trough extends from the African coast near 12N16W to
10N21W to 15N38W to 13N45W to 09N51W. The Intertropical
Convergence Zone axis extends from 09N51W to 07N58W. Aside from
the convection associated with the tropical waves...isolated
moderate convection is from 06N-09N between 27W-35W.

...DISCUSSION...

GULF OF MEXICO...
An upper level low is noted on water vapor imagery centered over
coastal Texas near 29N95W with axis extending S-SW to over central
Mexico near 20N100W while an upper level anticyclonic circulation
is centered over the NE Gulf near 27N86W. Only a few isolated
showers are occurring across the NW Gulf waters and portions of
extreme SE Texas N of 27N between 93W-96W as mostly dry air is
noted W of 91W. A tropical wave extends across the SW Gulf waters
with a fractured northern portion of the wave analyzed as a
surface trough from 22N91W to 28N89W. Scattered showers and tstms
are occurring from 23N-29N between 87W-91W focused in the vicinity
of the boundary. In addition...this convection is likely enhanced
due to the maximum middle to upper level diffluence generated
between the two upper level features. The wave is expected to
move W to WNW during the next 24 hours while weakening across the
SW Gulf and eastern Mexico through Sunday. Otherwise...an exposed
1012 mb low is centered in the SE Gulf near 24N83W with the
associated surface trough extending NE across southern and central
Florida...and SW from the low to the Yucatan Channel near 22N86W.
Most convection is well south and east of the low center with
isolated showers and tstms occurring across the Florida Straits
and portions of central and western Cuba into the Caribbean Sea.
Finally...gentle to moderate E-NE winds are expected to persist
through Sunday as surface ridging remains anchored to the north
across the SE CONUS and the troughing associated with the 1012 mb
low drifts westward across southern portions of the basin.

CARIBBEAN SEA...
The primary feature across the Caribbean this afternoon is a
tropical wave along 79W. Most of the convective activity
associated with the wave is noted across the SW Caribbean S of 12N
between 75W-85W. To the N...scattered showers and tstms are
occurring N of 17N between 77W-83W...however are more likely due
to favorable upper level diffluence over Cuba stretching south to
16N than the tropical wave itself. Otherwise...the remainder of
the basin is under the influence of mostly dry air aloft and
fairly stable conditions. Moderate to fresh trades prevail across
much of the basin with occasional strong trades expected through
Sunday across south-central portions.

...HISPANIOLA...
Fair weather conditions prevail across the island this afternoon
supported by subsidence aloft within northerly flow. A surface
trough analyzed across NE Hispaniola will move NW and provide
occasional isolated showers across across Hispaniola and the
adjacent Atlc coastal waters through the weekend.

ATLANTIC OCEAN...
An elongated upper level low is centered over Grand Bahama Island
near 27N78W that supports broad surface troughing...one focused
across the Florida peninsula and the other extending from 25N76W
to 29N71W. A fairly broad area of widely scattered showers and
tstms is associated with these features generally W of 70W. To the
SE...another area of interest...is a 1015 mb low centered N-NW of
Puerto Rico near 21N68W. A surface trough extends from NE
Hispaniola through the low center to 23N66W. Scattered showers and
tstms are occurring from 19N-24N between 62W-70W. This convection
is enhanced due to an upper level low centered near 19N69W.
Otherwise...the remainder of the central and eastern Atlc remains
under the influence of a surface ridge anchored by a 1028 mb high
centered near 34N40W.

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

$$
HUFFMAN
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