[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251011
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
611 AM EDT Wed Oct 25 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 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...TROPICAL WAVES...

A tropical wave is E of the Lesser Antilles with axis extending
from 19N56W to 07N58W. Interaction of the wave with an elongated
upper level trough across the E Caribbean with base extending into
S America is maintaining the wave nearly stationary. Satellite
derived data show the wave is in a region of strong vertical wind
shear. However, abundant low to middle level moisture and upper
level diffluence between the trough and a broad ridge over the
central Atlc support scattered moderate convection and isolated
tstms from 07N-19N between 50W-61W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 11N16W to
10N19W. The Intertropical Convergence Zone axis extends from
10N19W to 08N30W to 05N45W to 05N52W. Aside from the convection
associated with the tropical wave, scattered moderate to strong
convection and isolated tstms are from 02N-16N between 27W-50W
and from 06N-10N E of 16W.

...DISCUSSION...

GULF OF MEXICO...

A vigorous middle to upper level trough is over the Great Lakes
and Mississippi River valley with a broad base dipping southward
to near 26N over the northern Gulf. The deep layered trough
supports a cold front extending from south Florida near 25N81W SW
to the Yucatan peninsula near 21N86W to central Guatemala. Scattered
showers and isolated tstms are occurring within 90 nm E of the
front while isolated showers are within 75 nm W of the boundary.
Fresh to strong northerly winds associated with the passage of the
front are over the entire basin, which are expected to gradually
decrease in areal coverage and be confined to the Bay of Campeche
by tonight. Otherwise, surface high pressure continues to build
across the Gulf today into Thursday.

CARIBBEAN SEA...

A broad upper level ridge over the western Caribbean continues to
provide an overall divergent environment aloft. Underneath this
divergent flow, a 1006 mb low is centered off the coast of
Nicaragua near 13N82W, which is also connected to the EPAC monsoon
trough that then extends SE to inland NW Colombia. Numerous heavy
showers and scattered tstms associated with this system are over
Nicaragua while scattered heavy showers and tstms extend ESE
covering the region S of 16N between 74W-84W. Over the far NW
Caribbean, a surface pre-frontal trough along 21N82W to 15N87W
support scattered showers and tstms in the Gulf of Honduras and
elsewhere W of 80W. A surface trough extends from 21N60W to the
NE Caribbean near 15N64W and is generating isolated showers and
tstms over the Leeward and Virgin Islands. Showers are expected to
extend to Puerto Rico later this morning. A deep layered trough
covers the remainder basin with water vapor imagery showing strong
subsidence, which is supporting fair weather. In the far SE
Caribbean, proximity of a tropical wave with axis near 57W support
scattered to isolated showers across the Windward Islands. A cold
front currently moving across the Straits of Florida will move
into the NW Caribbean today increasing northerly winds into fresh
to strong levels through Thursday. Otherwise, moderate trades
dominate elsewhere.

...HISPANIOLA...

Dry air aloft within northerly flow will support fair weather
across the island through today and Thursday. Moderate trades are
expected to persist.

ATLANTIC OCEAN...

A middle to upper level trough continues to progress eastward out
of the Great Lakes and Mississippi River valley region towards
the eastern US seaboard this morning. The trough supports a cold
front extending from 30N77W to south Florida near 25N80W. Scattered
showers and isolated tstms are occurring ahead of the front
within 150 nm. The remainder of the SW North Atlc is under the
influence of a surface ridge anchored by a 1028 mb high centered
near 38N57W. To the E of the ridge, a cold front extends from
30N32W continuing to 28N36W where it becomes stationary to 25N42W
then it starts to dissipate. Scattered showers and tstms are
occurring W of the front from 25N- 29N between 50W- 59W. Weak
surface ridging is elsewhere N of 20N.

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

$$
Ramos
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