Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 271043
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT SEP 27 2014

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
1115 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE E ATLANTIC FROM 9N19W TO 16N19W MOVING
W AT 20 TO 25 KT. THE WAVE IS EMBEDDED IN AN AREA OF DEEP LAYER
MOISTURE S OF 15N. DRY SAHARAN AIR IS NOTED N OF 15N. SCATTERED
MODERATE CONVECTION IS FROM 11N TO 15N BETWEEN 19W AND 25W.

A TROPICAL WAVE IS IN THE E CARIBBEAN FROM 12N69W TO 22N68W AND
CROSSING THE DOMINICAN REPUBLIC...MOVING WESTWARD AT 15 KT. THE
WAVE IS INTERACTING WITH AN UPPER-LEVEL LOW AND IS PRODUCING A
LARGE AREA OF SCATTERED MODERATE CONVECTION FROM 12N TO 22N
BETWEEN 64W AND 76W. THE WAVE WILL CROSS THE CENTRAL CARIBBEAN
TODAY AND THE WESTERN CARIBBEAN SUNDAY. THE UPPER-LOW IS
FORECAST TO REMAIN NEAR PUERTO RICO AND THE UK/US VIRGIN ISLANDS
THROUGH THE WEEKEND KEEPING THE ATMOSPHERE VERY UNSTABLE WITH
THE POTENTIAL OF MORE SHOWERS AND TSTMS.

A TROPICAL WAVE EXTENDS FROM 12N91W TO 22N91W AND OVER THE BAY
OF CAMPECHE MOVING W AT 10 TO 15 KT. DEEP LAYER MOISTURE IS
ASSOCIATED WITH THIS WAVE. SCATTERED MODERATE CONVECTION IS N OF
17N BETWEEN 90W AND 94W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
7N37W AND THEN FROM A 1013 MB SURFACE LOW NEAR 13N43W TO 10N50W.
THE ITCZ EXTENDS FROM 10N50W TO THE S AMERICA COAST NEAR 10N62W.
ISOLATED MODERATE CONVECTION IS FROM 5N TO 8N BETWEEN 25W AND
35W. NO SIGNIFICANT CONVECTION IS NOTED ELSEWHERE.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH IS CENTERED ACROSS TX WITH AN UPPER RIDGE AXIS
EXTENDING FROM S MEXICO ACROSS THE S GULF. A SURFACE TROUGH
EXTENDS FROM 27N96W TO 29N84W. LOW LEVEL CONVERGENCE WITH THE
SURFACE TROUGH AND UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER
TROUGH AND RIDGE ARE SUPPORTING SCATTERED MODERATE CONVECTION
FROM 25N TO 28N BETWEEN 89W AND 97W. IN ADDITION...SCATTERED
SHOWERS ARE OCCURRING E OF 89W WITHIN 150NM OF THE SURFACE
TROUGH. SCATTERED SHOWERS ARE ALSO OCCURRING OVER THE SW GULF
NEAR ANOTHER SURFACE TROUGH THAT IS FROM 19N95W TO 24N95W. OTHER
CONVECTION IN THE SW GULF AND BAY OF CAMPECHE IS ASSOCIATED WITH
A TROPICAL WAVE MENTIONED IN THE TROPICAL WAVES SECTION.

CARIBBEAN SEA...

AN UPPER LEVEL LOW IS CENTERED NEAR PUERTO RICO WITH AN UPPER
TROUGH AXIS EXTENDING SW OF THIS LOW INTO THE SW CARIBBEAN.
UPPER LEVEL RIDGING IS ACROSS S MEXICO AND GUYANA. UPPER LEVEL
DIFFLUENCE BETWEEN THE UPPER LOW AND SURROUNDING UPPER RIDGES IS
SUPPORTING SCATTERED THUNDERSTORMS FROM 11N TO 19N BETWEEN 72W
AND 86W. SOME OF THIS CONVECTION IN THE CENTRAL CARIBBEAN IS
ASSOCIATED WITH A TROPICAL WAVE DISCUSSED IN THE TROPICAL WAVES
SECTION. OVER THE NEXT 24 HOURS THE UPPER LEVEL FEATURES ARE
FORECAST TO MOVE VERY LITTLE...WHILE THE TROPICAL WAVE CROSSES
THE CENTRAL CARIBBEAN. TRADE WINDS GENERALLY UNDER 15 KT ARE
EXPECTED TO CONTINUE OVER MOST OF THE BASIN.

...HISPANIOLA...
SCATTERED THUNDERSTORMS CONTINUE OVER HISPANIOLA AND OFFSHORE
WATERS AS AN UPPER LOW INTERACTS WITH AN APPROACHING TROPICAL
WAVE IN A MOIST AIRMASS. EXPECT ENHANCED COVERAGE OF SHOWERS AND
THUNDERSTORMS OVER THE WEEKEND AS THE UPPER LOW REMAINS NEARLY
STATIONARY AND THE TROPICAL WAVE CROSSES THE AREA.

ATLANTIC OCEAN...

A STATIONARY FRONT EXTENDS FROM 29N80W TO 31N78W. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING WITHIN 100 NM OF
EITHER SIDE OF THE FRONT. THIS FRONT IS EXPECTED TO GRADUALLY
DISSIPATE OVER THE WEEKEND. A 1014 MB LOW IS LOCATED NEAR 28N47W
DRIFTING NORTHWESTWARD. A SURFACE TROUGH EXTENDS FROM 24N51W
THROUGH THIS LOW TO 31N46W. AN UPPER TROUGH LOCATED ABOUT 200 NM
EAST OF THE SURFACE TROUGH IS SUPPORTING SCATTERED MODERATE
CONVECTION FROM 24N TO 31W BETWEEN 39W AND 46W. ANOTHER 1014 MB
LOW IS LOCATED NEAR 23N37W WITH A SURFACE TROUGH EXTENDING FROM
17N39W THROUGH THE LOW TO 29N28W. SCATTERED SHOWERS ARE
OCCURRING WITHIN 50NM OF THIS TROUGH AXIS. A NEARLY STATIONARY
SURFACE LOW OF 1013 MB IS LOCATED NEAR 13N44W. SCATTERED
MODERATE CONVECTION IS FROM 11N TO 15N BETWEEN 40W AND 45W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
LATTO



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