[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050533
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
133 AM EDT Wed Jul 5 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 0000 UTC surface analysis and satellite imagery through
0500 UTC.

...SPECIAL FEATURES...

A 1009 mb surface low is centered near 10N35W. A tropical wave
extends through the low from 06N to 20N. Scattered moderate and
isolated strong convection is located within 120 nm in low's
western semicircle. No observations of the peak winds have been
available in the last several hours, though it is likely that the
strongest winds are 25-30 kt. Environmental conditions remain
favorable for a tropical cyclone to form within the next day or
two while the low moves westward or west-northwestward at 10 to 15
mph across the tropical Atlantic. 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 near 50W
extending from about 10N to 22N, moving west at about 20 kt
during the last 24 hours. This wave had spun off the surface low
currently to the east of the wave axis. No significant deep convection
is observed within this wave at this time. The wave has little to
no surface circulation and has no signature in the Total
Precipitable Water imagery, though it is readily apparent at 700
mb in the SUNY-Albany Trough Diagnostics.

A tropical wave located over the eastern Caribbean has an axis
near 67W extending from about 09N to 21N, moving west at around
15 kt during the past 24 hours. ASCAT scatterometer and surface
station observations both show the wave has a well-defined
surface trough. Rawindsondes at Santo Domingo and San Juan as well
as the Trough Diagnostics suggest that the 700 mb wave axis may be
slightly westward of the surface trough.  Scattered moderate
convection prevails within 180 nm west of the axis north of 15N.

A tropical wave over the western Caribbean and Nicaragua/Honduras
has an axis near 84W from 10N to 20N, running from 19N81W to
11N82W. The wave is moving westward at about 15-20 kt. The wave
can be seen in as a trough in both surface observations and in 700
mb winds from Cayman Island, Cancun, Merida, and Belize City
rawindsondes. Scattered moderate and isolated strong convection is
located within 120 nm of the axis north of 15N. The combination
of a tropical upper tropospheric trough extending east-west at 23N
and this wave is helping to enhance this convection.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends from the Senegal coast at 14N17W to
the Special Feature low near 10N35W. No ITCZ is present currently.
Aside from the convection related to the Special Feature's
low/wave, scattered moderate isolated strong convection is
observed from 02N to 05W between 35W and 40W as well as north of
06N and east of 16W to the West African coast.

...DISCUSSION...

GULF OF MEXICO...

A weak surface ridge extends across the Gulf, anchored by a
surface high centered near 29N84W. A tropical upper tropospheric
trough extends east-west at 23N. Isolated showers in the
southeastern Gulf are being enhanced by this upper low.
Scatterometer, ship, and buoy observation indicate that the
surface winds across the Gulf are light to moderate breeze.
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 westernmost tropical
wave along 84W and a tropical upper tropospheric trough centered
along 23N. The moderate pressure gradient over the Caribbean
between the Bermuda high to the north and the Colombian low to
the south is maintaining gentle 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 trough
to weaken through Thursday, which should allow convection in this
area to decrease. Little change is expected in the surface winds
during the next couple of days.

...HISPANIOLA...

Scattered showers and isolated moderate convection developed over
the Haiti this afternoon and early evening, enhanced by diurnal
heating and orographic lifting. This is now diminishing.  Expect
convection to increase on Wednesday and Thursday as the moisture
associated with a tropical wave approaches 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.
Aside from the convection associated with surface low and monsoon
trough described above, no other significant convection is
currently occurring.  A broad 1031 mb surface high is centered
north of our area near 35N41W. 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 couple of days.

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

$$
Landsea
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