Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 271039
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUN 27 2015

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
1030 UTC.

...SPECIAL FEATURES...

...GALE WARNING CONTINUES IN THE CARIBBEAN SEA...

A GALE WARNING FOR MINIMAL GALE FORCE WINDS REMAINS IN EFFECT
FOR THE SW CARIBBEAN FROM 11N-17N BETWEEN 70W-79W THROUGH THE
AFTERNOON HOURS. THESE CONDITIONS WILL PULSE EVERY EVENING OVER
THE NEXT 48 HOURS. THESE WINDS ARE BEING GENERATED DUE TO A
TIGHT PRESSURE GRADIENT CREATED BETWEEN THE PERSISTENT STRONG
HIGH PRESSURE OVER THE WESTERN ATLANTIC AND THE LOWER PRESSURES
OVER SOUTH AMERICA AND THE SW CARIBBEAN SEA. SEE THE LATEST NWS
HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC
AND THE OFFSHORE FORECAST...MIAOFFNT3/ FZNT23 FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE FAR EASTERN TROPICAL ATLANTIC WITH
AXIS EXTENDING FROM 13N29W TO 03N29W...MOVING W AT 10-15 KT.
DESPITE THE FACT THAT THE SSMI TOTAL PRECIPITABLE WATER IMAGERY
SHOWS THE WAVE EMBEDDED IN LOW-LEVEL MOISTURE FROM 05N-10N...NO
CONVECTION IS OBSERVED ALONG THIS WAVE AS A BROAD SAHARAN
AIRMASS PREVAILS ACROSS THE TROPICAL ATLANTIC INHIBITING
CONVECTION.

A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLANTIC WITH AXIS
EXTENDING FROM 14N48W TO 04N48W...MOVING W AT 10-15 KT UNDER THE
SOUTHERN PERIPHERY OF A STRONG ATLANTIC HIGH PRESSURE. THE SSMI
TOTAL PRECIPITABLE WATER IMAGERY ALSO SHOWS THIS WAVE EMBEDDED
IN DEEP LOW-LEVEL MOISTURE AND WITH THE SAHARAN DUST SURGE TO
THE N OF 12N...ISOLATED CONVECTION IS OBSERVED E OF THE WAVE
AXIS S OF 09N BETWEEN 27W-35W. THIS WAVE IS LIKELY TO AMPLIFY
SOME IN LONGITUDINAL SIZE AS IT MOVES FARTHER W DURING THE NEXT
24-48 HOURS.

A TROPICAL WAVE CURRENTLY ENTERING THE E CARIBBEAN WITH AXIS
EXTENDING FROM 19N62W TO 10N62W...MOVING W AT 10-15 KT. LATEST
SATELLITE IMAGERY CONTINUES TO SHOW AN INVERTED-V SHAPE LOW-
LEVEL CLOUD PATTERN AND THE SSMI TOTAL PRECIPITABLE WATER
IMAGERY SHOWS THIS WAVE EMBEDDED IN AN AREA OF HIGH LOW-LEVEL
MOISTURE WHICH IS SUPPORTING ISOLATED CONVECTION ACROSS THE E
CARIBBEAN MAINLY E OF 76W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL
ATLANTIC NEAR 13N17W THROUGH 07N27W. THE ITCZ BEGINS W OF A
TROPICAL WAVE NEAR 07N32W TO 06N48W. SCATTERED MODERATE
CONVECTION IS OBSERVED FROM 06N-09N BETWEEN 32W-43W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER-LEVEL LOW IS CENTERED OVER THE NW GULF NEAR 25N96W AND
EXTENDING E OVER MOST OF THE BASIN MAINLY W OF 86W. A WEAK UPPER-
LEVEL HIGH IS DEVELOPING OVER THE YUCATAN CHANNEL NEAR 23N87W.
TO THE E...ANOTHER UPPER-LEVEL HIGH IS CURRENTLY OVER THE
FLORIDA PENINSULA NEAR 27N82W AND PREVAILING ACROSS THE E GULF E
OF 86W. THESE FEATURES ARE GENERATING A DIFFLUENT FLOW ACROSS
THE S CENTRAL GULF SUPPORTING CLOUDINESS AND ISOLATED CONVECTION
S OF 28N BETWEEN 88W-93W. SCATTERED MODERATE CONVECTION IS
OBSERVED ACROSS THE BAY OF CAMPECHE S OF 21N BETWEEN 94W-97W. AT
THE SURFACE...A 1018 MB HIGH PRESSURE IS CENTERED NEAR 26N88W
SUPPORTING A LIGHT TO GENTLE ANTICYCLONIC FLOW ACROSS THE BASIN
AND FAIR WEATHER. AN AREA OF GENTLE TO MODERATE WINDS IS
DEPICTED IN SCATTEROMETER DATA OVER THE BAY OF CAMPECHE MAINLY S
OF 22N BETWEEN 91W-96W. A SIMILAR WEATHER PATTERN IS EXPECTED
OVER THE NEXT 24 HOURS. A FRONTAL BOUNDARY WILL APPROACH THE NW
GULF WATERS SUPPORTING CONVECTION.

CARIBBEAN SEA...

A NARROW UPPER-LEVEL RIDGE IS CENTERED OVER THE YUCATAN CHANNEL
WHILE AN UPPER-LEVEL LOW EXTENDS ITS TROUGH FROM THE SW ATLANTIC
OVER E CUBA AND THE NORTHERN HALF OF THE CARIBBEAN. THIS PATTERN
IS SUPPORTING ISOLATED CONVECTION ACROSS THE ADJACENT WATERS S
OF CUBA WHILE THE CENTRAL PORTION OF THE BASIN CONTINUES WITH
FAIR WEATHER AS A SAHARAN AIRMASS PREVAILS INHIBITING
CONVECTION. A TROPICAL WAVE IS ENTERING THE E CARIBBEAN
GENERATING ENOUGH INSTABILITY TO SUPPORT ISOLATED CONVECTION
ACROSS THIS AREA. FOR MORE INFORMATION PLEASE REFER TO THE
SECTION ABOVE. A GALE WARNING CONTINUES IN EFFECT FOR THE WATERS
N OF COLOMBIA. FOR MORE INFORMATION...PLEASE REFER TO THE
SECTION ABOVE. GENTLE TO MODERATE TRADES ARE DEPICTED IN
SCATTEROMETER DATA ACROSS THE REMAINDER OF THE BASIN. OVER THE
NEXT 24 HOURS...EXPECT FOR THE TROPICAL WAVE TO CONTINUE MOVING
W ACROSS THE E CARIBBEAN INCREASING THE LOW-LEVEL MOISTURE AND
HENCE SUPPORTING ISOLATED CONVECTION ACROSS THE GREATER
ANTILLES.

...HISPANIOLA...

FAIR WEATHER PREVAILS ACROSS THE AREA TONIGHT. A TROPICAL WAVE
CURRENTLY JUST OVER THE LEEWARD ISLANDS SHOULD APPROACH
HISPANIOLA OVER THE NEXT 24 HOURS INCREASING THE LOW-LEVEL
MOISTURE AND HENCE SUPPORTING ISOLATED CONVECTION IN THE
AFTERNOON HOURS.

ATLANTIC OCEAN...

THE BASIN IS UNDER THE INFLUENCE OF A BROAD 1027 MB SURFACE HIGH
CENTERED NEAR 29N47W. AT UPPER-LEVELS...A PAIR OF UPPER-LEVEL
LOWS CENTERED NEAR 21N75W AND 27N67W ARE SUPPORTING ISOLATED
CONVECTION N OF 24N AND W OF 74W AFFECTING THE BAHAMAS AND THE W
ATLANTIC WATERS. FAIR WEATHER PREVAILS ACROSS THE REMAINDER OF
THE BASIN AS A BROAD SAHARAN AIRMASS CONTINUES ACROSS THE
TROPICAL ATLANTIC AS DEPICTED BY THE NOAA/NESDIS AEROSOL PRODUCT
AND LATEST VISIBLE SATELLITE IMAGERY. THREE TROPICAL WAVES WERE
ANALYZED ACROSS THE BASIN...PLEASE REFER TO THE SECTION ABOVE
FOR MORE INFORMATION. OVER THE NEXT 24 HOURS...EXPECT FOR THE
SURFACE HIGH AND SAHARAN DUST TO PREVAIL ACROSS THE BASIN WITH
FAIR WEATHER.

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

$$

ERA


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