[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291808
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
208 PM EDT Sat Jul 29 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...TROPICAL WAVES...

A tropical wave is in the E Atlc with axis extending from 17N26W
to 07N26W, moving west at 10 kt. SSMI TPW imagery depicts the wave
with a moisture area. The wave is in a region of low vertical
wind shear and has Saharan dry air and dust north of 13N and west
of 26W. Scattered moderate convection is from 06N-10N between
24W-28W.

A tropical wave is in the central Atlc with axis extending from
18N42W to 06N42W, moving W at 10 kt. SSMI TPW imagery shows a
narrow spike of moisture south of 26N between 42W-47W. The wave
is in a region of low vertical wind shear, and is being severely
affected by Saharan dry air and dust east and west of the wave
axis. No significant convection is noted.

A tropical wave is in the central Atlc with axis extending from
22N54W to 09N55W, moving west at 15 kt. The wave is in a moderate
to strong vertical wind shear environment and continues to be
severely affected by Saharan dry air and dust intrusion to its
environment. No significant convection is noted.

A tropical wave is in the central Caribbean with axis extending
from 20N70W to 10N71W, moving W at 10 kt. Water vapor imagery
depict dry subsident air over the wave also noticed in the CIRA
LPW imagery. Besides dry air, strong vertical wind shear is in the
central Caribbean, which is influencing the lack of deep
convection at this time.

A tropical wave is in the W Caribbean with axis extending from
21N86W to 06N86W, moving W at 15 kt. SSMI TPW imagery depicts the
wave with a moisture area south of 17N. Scattered showers are
inland over Central America within 180 nm of the wave axis.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from 12N16W to 10N20W to 04N30W to
08N37W to 09N45W. The ITCZ extends from 09N45W to 09N60W. Besides
the convection mentioned in the tropical wave section, widely
scattered moderate convection is along the coast of W Africa from
06N-13N between 14W-21W. Scattered moderate to isolated strong
convection is from 08N-11N between 29W-34W. Widely scattered
moderate convection is from 08N-10N between 49W-53W.

...DISCUSSION...

GULF OF MEXICO...

A cold front is inland over the north Gulf of Mexico States
producing scattered moderate convection from 29N-32N between
85W-93W. A weak surface ridge prevails across the basin with axis
along 26N. Water vapor imagery and satellite derived winds
indicate NW flow aloft covering most of the Gulf, with an upper
level high centered over northern Texas at 35N100W. Expect the
front to dip south over the northern Gulf on Sun with winds
shifting to the north. Also expect 20 kt SW to W winds south of
the front.

CARIBBEAN SEA...

Two tropical waves are moving across the basin. See above.
Elsewhere, the extension of the Pacific monsoon trough is
producing scattered moderate convection over the SW Caribbean,
Costa Rica, Panama, and N Colombia, S of 12N. Scatterometer data
shows 10-25 kt trades with strongest winds over the central
Caribbean. In the upper levels, a small upper level low is
centered over W Cuba near 21N80W. A small upper level high is
centered over the SW Caribbean near 12N79W. Expect the SW
Caribbean to continue to produce convection over the next 24
hours.

...HISPANIOLA...

Presently scattered showers are over Hispaniola due to the
northern extent of a tropical wave and afternoon heating. Expect
more showers Sun afternoon and evening due to max heating.

ATLANTIC OCEAN...

Three tropical waves are movingsin. See above. A
large 1027 mb high is centered over the central Atlantic near
32N37W producing fair weather. In the upper levels, a trough is
over the W Atlantic N of 28N and W of 70W. Scattered showers and
isolated thunderstorms are over this area. Upper level diffluence
is also over the central Bahamas producing similar precipitation.
A small upper level low is centered near 30N57W also producing
similar precipitation within 300 nm of the center.

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

$$
Formosa
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