Tropical Weather Discussion
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000
AXNT20 KNHC 271805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...SPECIAL FEATURES...

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

A GALE WARNING REMAINS IN EFFECT FOR THE SW CARIBBEAN FROM 11N-
15N BETWEEN 72W-78W THROUGH THE AFTERNOON HOURS. THESE
CONDITIONS WILL PULSE EVERY EVENING OVER THE NEXT 48 HOURS. GALE
WINDS ARE BEING SUPPORTED BY A TIGHT PRESSURE GRADIENT BETWEEN
THE PERSISTENT STRONG HIGH PRESSURE OVER THE WESTERN ATLANTIC
AND THE LOWER PRESSURES OVER NW COLOMBIA 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 CENTRAL TROPICAL ATLANTIC WITH AXIS
ALONG 36W FROM 03N TO 11N...MOVING W AT 15-20 KT. THE SSMI TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED MAINLY IN A
MODERATE MOIST ENVIRONMENT EXCEPT AHEAD OF ITS AXIS WHERE A
ABUNDANT MOISTURE IS OBSERVED SUPPORTING SCATTERED MODERATE
CONVECTION FROM 05N TO 09N BETWEEN 37W AND 44W. SAHARAN DRY AIR
AND DUST ARE INHIBITING CONVECTION IN THE NORTHERN WAVE
ENVIRONMENT.

A TROPICAL WAVE IS OVER THE WESTERN TROPICAL ATLANTIC WITH AXIS
NEAR 54W FROM 05N TO 14N...MOVING W AT 15 KT UNDER THE SOUTHERN
PERIPHERY OF A STRONG ATLANTIC HIGH PRESSURE. THE SSMI TOTAL
PRECIPITABLE WATER IMAGERY SHOW THIS WAVE IS EMBEDDED IN A
MODERATE MOIST ENVIRONMENT BEING INFLUENCED BY THE PRESENCE OF
SAHARAN DRY AIR AND DUST N OF 10N. ISOLATED MODERATE CONVECTION
IS WITHIN 100 NM AHEAD OF THE WAVE AXIS FROM 08N TO 10N.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AXIS NEAR 69W
...MOVING W AT 15-20 KT. THE SSMI TOTAL PRECIPITABLE WATER
IMAGERY SHOWS THIS WAVE IS EMBEDDED IN A MODERATE MOIST
ENVIRONMENT THAT ALONG AN UPPER LEVEL DIFFLUENT ENVIRONMENT
SUPPORT ISOLATED SHOWERS AND TSTMS ACROSS EASTERN DOMINICAN
REPUBLIC...MONA PASSAGE AND PUERTO RICO...INCLUDING ADJACENT
WATERS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL
ATLANTIC NEAR 10N14W TO 07N23W TO 07N32W. THE ITCZ BEGINS W OF A
TROPICAL WAVE NEAR 06N38W TO 07N53W. ASIDE THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION
IS FROM 05N-10N E OF 21W.

...DISCUSSION...

GULF OF MEXICO...

A MIDDLE TO UPPER LEVEL LOW IS OVER THE W GULF...WHICH ALONG
WITH MODERATE MOISTURE ADVECTED FROM THE NW CARIBBEAN DURING THE
LAST 24 HOURS SUPPORT SCATTERED SHOWERS AND TSTMS FROM 20N TO
28N W OF 90W. MIDDLE TO UPPER LEVEL RIDGING AND DRY AIR
SUBSIDENCE DOMINATE THE REMAINDER BASIN THUS SUPPORTING FAIR
WEATHER. AT THE SURFACE...BROAD HIGH PRESSURE OVER THE CENTRAL
ATLC EXTENDS A RIDGE AXIS SW TO W ACROSS THE FLORIDA PENINSULA
TO 94W. THE SURFACE RIDGE OVER THE GULF IS BEING ANCHORED BY A
1019 MB HIGH LOCATED NEAR 25N88W THAT PROVIDES VARIABLE WINDS OF
5 KT E OF 93W...SE WIND FLOW OF 10-15 KT IS ACROSS THE REMAINDER
WESTERN BASIN. A SIMILAR WEATHER PATTERN IS EXPECTED OVER THE
NEXT 48 HOURS.

CARIBBEAN SEA...

GALE FORCE WINDS CONTINUES ALONG THE COAST OF COLOMBIA THROUGH
THIS AFTERNOON...FORECAST TO PULSE DURING THE NEXT TWO DAYS. SEE
THE SPECIAL FEATURES SECTION FOR MORE DETAILS. THE OTHER FEATURE
OF INTEREST IS A TROPICAL WAVE STARTING TO MOVE ACROSS THE CENTRAL
CARIBBEAN THAT IS ENHANCING SHOWERS N OF 16N E OF ITS
AXIS...INCLUDING DOMINICAN REPUBLIC...THE MONA PASSAGE...PUERTO
RICO AND ADJACENT SOUTHERN WATERS. SEE THE TROPICAL WAVES SECTION.
DEEP LAYER DRY AIR DOMINATES THE REMAINDER CENTRAL AND WESTERN
CARIBBEAN AS DEPICTED BY SSMI TPW AND WATER VAPOR IMAGERY...THUS
SUPPORTING FAIR WEATHER. DRY...DUSTY AND HAZY CONDITIONS
PREVAILS IN THIS REGION DUE TO THE PASSAGE OF A SAHARAN AIRMASS
FEW DAYS AGO. THE TROPICAL WAVE WILL MOVE TO WESTERN CARIBBEAN
WATERS BY SUNDAY MORNING WHILE A NEW WAVE MOVE ACROSS THE LESSER
ANTILLES.

...HISPANIOLA...

A TROPICAL WAVE IS S OF DOMINICAN REPUBLIC WITH ASSOCIATED MODERATE
MOISTURE EXTENDING ACROSS THE EASTERN REPUBLIC AND ADJACENT
WATERS. AN UPPER LEVEL LOW N OF THE ISLAND EXTENDS A TROUGH SW
TO JAMAICA AND GENERATES A DIFFLUENT ENVIRONMENT ALOFT THAT
SUPPORT ISOLATED SHOWERS AND TSTMS E OF 70W...INCLUDING THE MONA
PASSAGE. SHOWERS ARE EXPECTED TO CONTINUE THROUGH MONDAY AS THE
WAVE CONTINUES TO MOVE W AND THE UPPER LOW AMPLIFIES.

ATLANTIC OCEAN...

A MIDDLE LEVEL ELONGATED TROUGH IS OVER THE FAR SW N ATLC WATERS
ALONG WITH A BROAD MODERATE MOIST AIRMASS AHEAD OF A FRONTAL
SYSTEM TO MOVE OVER THE SE CONUS DURING THE NEXT COUPLE OF DAYS.
THIS ENVIRONMENT SUPPORT A LINE OF SHOWERS AND TSTMS W OF 73W.
THE REMAINDER BASIN IS UNDER THE INFLUENCE OF A BROAD 1027 MB
SURFACE HIGH CENTERED NEAR 29N49W THAT SUPPORT FAIR WEATHER.

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

$$
NR



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