Tropical Weather Discussion
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000
AXNT20 KNHC 301805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE JUN 30 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-FORCE WINDS CONTINUES ALONG THE COASTAL WATERS OF COLOMBIA
FROM 11.5N TO 13N BETWEEN 74W AND 77W WITH ASSOCIATED SEAS
RANGING FROM 10 TO 15 FT. WINDS WILL DIMINISH BELOW GALE-FORCE
THIS AFTERNOON...HOWEVER RESUMING TONIGHT. PLEASE READ THE HIGH
SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...AND THE OFFSHORE
FORECAST...MIAOFFNT3/FZNT23 KNHC...FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC WITH AXIS NEAR 29W
FROM 04N TO 12N...MOVING W AT 15-20 KT. METEOSAT AIRMASS...SAL
TRACKING AND PSEUDO-NATURAL COLOR IMAGERY DEPICT SAHARAN DRY AIR
AND DUST IN THE NORTHERN WAVE ENVIRONMENT. THE SOUTHERN PORTION
OF THE WAVE IS EMBEDDED IN THE ITCZ WHERE ABUNDANT MOISTURE
SUPPORT SCATTERED MODERATE CONVECTION FROM 06N TO 08N BETWEEN
25W AND 34W.

A TROPICAL WAVE IS E OF THE LESSER ANTILLES WITH AXIS NEAR
59W...MOVING W AT 15-20 KT. SSMI TPW IMAGERY SHOW THE WAVE IS
EMBEDDED IN AN ABUNDANT MOIST ENVIRONMENT THAT ALONG WITH A
DIFFLUENT ENVIRONMENT ALOFT SUPPORT SCATTERED MODERATE
CONVECTION FROM 10N TO 13N BETWEEN 57W AND 64W AND ISOLATED
SHOWERS FROM 13N TO 17N BETWEEN 55W AND 64W.

A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS NEAR
66W...MOVING W AT 15 KT. SSMI TPW IMAGERY SHOW THE WAVE IS
MAINLY EMBEDDED IN A DRY ENVIRONMENT...EXCEPT N OF 16N WHERE A
PATCH OF MODERATE MOISTURE ENHANCES SCATTERED TO ISOLATED
SHOWERS AND TSTMS OVER PUERTO RICO AND ADJACENT WATERS AND THE
U.S. VIRGIN ISLANDS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF GUINEA-
BISSAU NEAR 11N15W TO 09N21W. THE ITCZ BEGINS NEAR 09N21W AND
CONTINUES TO 08N28W...RESUMING NEAR 07N31W THEN CONTINUING ALONG
05N41W TO 06N49W TO 08N56W. ASIDE THE CONVECTION ASSOCIATED WITH
THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 07N TO
10N E OF 25W AND WITHIN 75 NM EITHER SIDE OF THE ITCZ BETWEEN
35W AND 50W.

...DISCUSSION...

GULF OF MEXICO...

THE NORTHERN PERIPHERY OF AN ELONGATED UPPER RIDGE ANCHORED
OVER THE EPAC WATERS SW OF GUATEMALA COVERS THE WESTERN GULF S
OF 26N. N OF 26N THE BASE OF AN UPPER TROUGH EXTENDING ACROSS
THE EASTERN CONUS GENERATES A DIFFLUENT ENVIRONMENT THAT ALONG
WITH ABUNDANT MOISTURE BEING ADVECTED FROM THE CARIBBEAN SUPPORT
SCATTERED MODERATE CONVECTION AND TSTMS FROM 21N TO 27N W OF 91W
AND N OF 28N BETWEEN SW LOUISIANA AND GALVESTON TEXAS. MAINLY
DRY AIR COVERS THE EASTERN BASIN...EXCEPT FOR SOME PATCHES OF
MODERATE MOIST AIR THAT ALONG WITH AN UPPER-LEVEL LOW CENTERED
NEAR 26N84W SUPPORT SCATTERED CLOUDS WITH POSSIBLE ISOLATED
SHOWERS OVER THE SE GULF E OF 85W...INCLUDING THE STRAITS OF
FLORIDA. OTHERWISE...SURFACE HIGH PRESSURE AND RIDGING DOMINATE
ACROSS THE BASIN BEING ANCHORED BY A 1021 MB HIGH NEAR 26N84W.
EXCEPT FOR SURFACE TROUGHING IN THE BAY OF CAMPECHE...SURFACE
HIGH PRESSURE AND RIDGING WILL DOMINATE ACROSS THE BASIN THE
NEXT TWO DAYS.

CARIBBEAN SEA...

GALE-FORCE WINDS CONTINUES ALONG COLOMBIA COASTAL WATERS THROUGH
THIS AFTERNOON. FOR MORE INFORMATION SEE SPECIAL FEATURES. A
TROPICAL WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN WITH AXIS JUST
EAST OF PUERTO RICO. AN UPPER LEVEL LOW AHEAD OF THE WAVE
CENTERED N OF HISPANIOLA ALONG WITH A PATCH OF MODERATE MOISTURE
SUPPORT SCATTERED TO ISOLATED MODERATE CONVECTION AND TSTMS
ACROSS PUERTO RICO AND N-NW ADJACENT WATERS. ANOTHER TROPICAL WAVE
APPROACHES THE LESSER ANTILLES ASSOCIATED WITH A BULGE OF
MOISTURE THAT CURRENTLY ENHANCES SCATTERED MODERATE CONVECTION
AND ISOLATED TSTMS OVER THE SE CARIBBEAN S OF 15N E OF 65W. SEE
TROPICAL WAVES SECTION ABOVE FOR MORE DETAILS. A 1010 MB LOW IS
JUST OFF THE COAST OF NW COLOMBIA NEAR 9N76W THUS ENHANCING
SCATTERED TO ISOLATED SHOWERS S OF 13N. SIMILAR CONVECTION IS
OVER NORTHERN HISPANIOLA ALONG WITH TSTMS BEING SUPPORTED BY THE
UPPER LEVEL LOW AND A MIDDLE LEVEL INVERTED TROUGH. ELSEWHERE
DEEP LAYER DRY AIR DOMINATES...THUS SUPPORTING FAIR WEATHER. THE
TWO TROPICAL WAVES WILL BE THE MAIN FEATURE ACROSS THE BASIN DURING
THE NEXT TWO DAYS.

...HISPANIOLA...

AN UPPER-LEVEL LOW IS CENTERED JUST N OF HISPANIOLA THAT ALONG
WITH A MODERATE MOIST AIRMASS SUPPORT SCATTERED TO ISOLATED
SHOWERS AND TSTMS MAINLY ACROSS THE NORTHERN DOMINICAN REPUBLIC
AND ADJACENT WATERS. A TROPICAL WAVE WILL BE MOVING ACROSS THE
CENTRAL BASIN WED ASSOCIATED WITH A MODERATE AIRMASS IN ITS
NORTHERN ENVIRONMENT THAT WILL ENHANCE SHOWERS ACROSS THE ISLAND
DURING THE DAY.

ATLANTIC OCEAN...

A MIDDLE-LEVEL TROUGH CONTINUES ACROSS THE SW N ATLC WATERS THUS
SUPPORTING SCATTERED TO ISOLATED MODERATE CONVECTION AND TSTMS N
OF 25N BETWEEN 71W AND 80W. SIMILAR CONVECTION IS ON THE
DOMINICAN REPUBLIC AND PUERTO RICO NORTHERN OFFSHORE WATERS. AN
UPPER TROUGH OVER THE E PAC CONTINUE TO SUPPORT A DISSIPATING
COLD FRONT THAT EXTENDS FROM 29N33W TO 28N46W TO 27N55W. RIDGING
AND HIGH PRESSURE DOMINATES ELSEWHERE.

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

$$
NR


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