Tropical Weather Discussion
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000
AXNT20 KNHC 212355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 21 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE CONTINUES OVER THE TROPICAL ATLANTIC EXTENDING
FROM 17N34W TO 7N36W. THE WAVE IS MOVING W AT 15 KT. SSMI TPW
SHOWS A MOIST AREA S OF 12 N ALONG THE WAVE. SSMI TPW AND
METEOSAT SAL IMAGERY INDICATE DRY AIR WITH EMBEDDED DUST N OF
13N. SCATTERED MODERATE CONVECTION IS OCCURRING S OF 13N BETWEEN
31W AND 37W.

A TROPICAL WAVE IS CROSSING THE LESSER ANTILLES WITH AXIS
EXTENDING FROM 21N59W TO 11N62W...MOVING WEST AT 15-20 KT. SSMI
TPW SHOWS A LARGE MOIST AREA FROM 6N-22N BETWEEN 47W-63W.
SCATTERED MODERATE CONVECTION AND ISOLATED STRONG CONVECTION ARE
FROM 8N-19N BETWEEN 54W AND 65W WHICH INCLUDES THE WINDWARD AND
LEEWARD ISLANDS.

A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN SEA WITH AXIS
EXTENDING FROM 22N81W TO 10N81W...MOVING W AT 15-20 KT. DEEP
LAYER MOISTURE IS IN THE ENVIRONMENT OF THIS WAVE. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 100 NM OF THE WAVE
AXIS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 17N16W TO
A 1009 MB LOW S OF THE CAPE VERDE ISLANDS NEAR 13N24W TO 10N35W
TO 8N45W. THE ITCZ AXIS EXTENDS FROM 8N45W TO 11N59W. OTHER THAN
THE CONVECTION MENTIONED IN THE TROPICAL WAVES SECTION
...WIDELY SCATTERED MODERATE CONVECTION IS FROM 11N-19N BETWEEN
17W AND 31W. SCATTERED MODERATE CONVECTION IS ALSO FROM 7N-14N
BETWEEN 37W AND 46W.

...DISCUSSION...

GULF OF MEXICO...

A QUASI-STATIONARY FRONT EXTENDS FROM CENTRAL FLORIDA NEAR
28N81W TO THE NORTH CENTRAL GULF OF MEXICO NEAR 27N92W. ISOLATED
MODERATE CONVECTION IS WITHIN 200 NM OF THE FRONT...INCLUDING
CENTRAL AND SOUTH FLORIDA. AN UPPER LEVEL TROUGH EXTENDS ACROSS
THE CENTRAL GULF. UPPER LEVEL DIFFLUENCE S OF THE BASE OF THE
TROUGH IS ENHANCING CONVECTION ACROSS THE SW GULF S OF 24N
BETWEEN 87W AND 91W. A NEARLY STATIONARY SURFACE TROUGH IS OVER
THE W GULF AND BAY OF CAMPECHE FROM 25N97W TO 18N96W. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING WITHIN 100 NM
OF THE SURFACE TROUGH. OVER THE NEXT 24 HOURS...THE STATIONARY
FRONT WILL GRADUALLY DISSIPATE WITH ONGOING CONVECTION EXPECTED
IN THE VICINITY OF THE DISSIPATING FRONT. OTHER CONVECTION WILL
BE POSSIBLE OVER THE SE GULF UNDER THE BASE OF AN EASTWARD
SHIFTING UPPER TROUGH. ANOTHER COLD FRONT IS FORECAST TO ENTER
THE N GULF ON TUESDAY.

CARIBBEAN SEA...

TWO TROPICAL WAVES ARE AFFECTING THE CARIBBEAN. SEE THE TROPICAL
WAVES SECTION ABOVE. OTHER THAN THE CONVECTION ASSOCIATED WITH
THE TROPICAL WAVES...A SMALL AREA OF UPPER LEVEL DIFFLUENCE IS
SUPPORTING A PATCH OF SCATTERED MODERATE CONVECTION OVER THE
CENTRAL CARIBBEAN FROM 15N-18N BETWEEN 65W AND 69W.
THUNDERSTORMS OVER THE GREATER ANTILLES ARE ASSOCIATED MAINLY
WITH DAYTIME HEATING AND THE PRESENCE OF DEEP LAYER MOISTURE.
OVER THE NEXT 24 HOURS...THE TROPICAL WAVE OVER THE LESSER
ANTILLES WILL SHIFT W WHICH WILL BRING ENHANCED CONVECTION TO
THE E CARIBBEAN INCLUDING PUERTO RICO AND SURROUNDING ISLANDS.
THE TROPICAL WAVE OVER THE W CARIBBEAN WILL MOVE ONSHORE THE
YUCATAN AND CENTRAL AMERICA.

...HISPANIOLA...

SCATTERED THUNDERSTORMS ARE OCCURRING OVER HISPANIOLA MAINLY DUE
TO DAYTIME LANDMASS HEATING IN A MOIST AIRMASS. EXPECT A
TROPICAL WAVE TO PRODUCE ADDITIONAL CONVECTION IN 24-48 HOURS.

ATLANTIC OCEAN...

A 1009 MB LOW S OF THE CAPE VERDE ISLANDS AND TWO TROPICAL WAVES
ARE THE MAIN FEATURES ACROSS THE BASIN. SEE THE TROPICAL WAVES
SECTION AND MONSOON/ITCZ SECTION ABOVE. A COLD FRONT EXTENDS
FROM 31N73W TO 28N77W. A STATIONARY FRONT CONTINUES FROM 28N77W
TO CENTRAL FLORIDA NEAR 28N81W. WIDELY SCATTERED MODERATE
CONVECTION IS WITHIN 150 NM S AND E OF THE COLD FRONT. SCATTERED
SHOWERS AND THUNDERSTORMS ARE WITHIN 150 NM S OF THE STATIONARY
FRONT TO INCLUDE THE N BAHAMAS. AN UPPER LOW CENTERED NEAR
27N50W AND UPPER LEVEL DIFFLUENCE NORTH OF THE UPPER LOW IS
SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS FROM 26N-33N
BETWEEN 45W AND 52W. OVER THE NEXT 24 HOURS...THE FRONTS OVER
THE W ATLANTIC WILL BEGIN TO DISSIPATE WITH POSSIBLE ONGOING
CONVECTION IN THOSE LOCATIONS. A COLD FRONT WILL DIP SOUTH INTO
THE CENTRAL ATLANTIC WITH SHOWERS POSSIBLE WITH THIS FRONT. THE
UPPER LOW WILL CONTINUE TO PRODUCE SHOWERS AND ISOLATED
THUNDERSTORMS AS IT REMAINS NEARLY STATIONARY.

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

$$ LATTO


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