[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 042339
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
739 PM EDT Tue Jul 4 2017

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.

...SPECIAL FEATURES...

A 1010 mb surface low is centered near 11N34W. A tropical wave
extends from 20N32W to the low to 07N35W. At this time, only isolated
moderate convection is located in the northeast and southwest
quadrants of the low within 360 nm of the center. The low is
surrounded by a large area of cyclonic winds extending about 400
nm from the center. The latest satellite- derived wind data shows
peak winds of near gale force in the southeastern quadrant. The
low is expected to move slowly northwest through the next 24
hours. The system retains a high chance of becoming a tropical
cyclone during the next 48 hours.

...TROPICAL WAVES...

A tropical wave over the central Atlantic has an axis extending
from 22N45W to 10N50W, moving west at about 15-20 kt during the
last 24 hours. This wave had spun off the surface low currently to
the east of the wave axis. No convection is observed within this
wave at this time.

A tropical wave located over the eastern Caribbean has an axis
reaching from 20N64W to 10N66W, moving west at around 15 kt
during the past 24 hours. Satellite-derived wind data and surface
station observations both show the wave has a well defined surface
trough. Scattered moderate convection prevails south of 20N
between 60W-70W affecting the Leeward Islands and Puerto Rico.

A tropical wave over the western Caribbean has an axis running
from 19N81W to 11N82W. The wave is moving westward at about 15-20
kt. The wave only exhibits troughing in surface observations and
initial 700 mb model fields. The combination of an upper-level low
centered to the north of the wave and this feature is enhancing
convection along and west of the wave's axis between 80W-90W
affecting Central America and the Yucatan Peninsula.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends from 14N17W to the Special Feature low
near 11N35W to 09N46W. The ITCZ extends from 10N53W to 09N61W.
Aside from the convection related to the Special Feature's
low/wave, no significant convection is observed elsewhere.

...DISCUSSION...

GULF OF MEXICO...

A surface ridge extends across the basin, anchored by a stationary
surface high centered near 30N86W. An elongated upper-level low
is centered near the Yucatan Channel near 22N85W. Isolated showers
are prevailing south of 25N enhanced by this low. Scatterometer
data depicts light to gentle anticyclonic winds across the basin.
Little change in this pattern is expected during the next couple
of days.

CARIBBEAN SEA...

Two tropical waves are moving across the basin. Refer to the
section above for details. The convection over the western
Caribbean is related to the combination to the tropical wave along
82W and an upper-level low centered over the Yucatan Channel.
Convection is also present over Puerto Rico and the Leeward
Islands related to the wave with axis along 65W. The moderate
pressure gradient over the Caribbean between the high to the north
and the Colombian low to the south is maintaining moderate to
fresh tradewinds over the basin, except over the waters north of
Colombia and Venezuela where fresh to strong easterlies are
pulsing every night lasting through the early morning hours.
Expect for the upper-level low to weaken and move northwest
through Thursday, which should allow convection in this area to
decrease.

...HISPANIOLA...

Scattered showers have developed over the western portion of the
island enhanced by diurnal heating and orographic lifting. Expect
convection to increase on Wednesday as the moisture associated
with a tropical wave that will approach from the east.


ATLANTIC OCEAN...

Two tropical waves are analyzed over the basin. Refer to the
Special Features and Tropical Waves sections above for details.
A broad 1029 mb surface high is centered near 37N38W and extends
across the remainder of the region. The high continues to
dominate the weather across the tropical north Atlantic. To the
south of the high and away from the surface low described above,
moderate to fresh trade winds prevail across the basin. This
synoptic pattern will change little through the next 24 hours.

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

$$

ERA
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