Tropical Weather Discussion
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000
AXNT20 KNHC 301737
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 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
1715 UTC.

...SPECIAL FEATURES...
GALE-FORCE WINDS THAT WERE OCCURRING OVER THE SW CARIBBEAN THIS
MORNING ARE FORECAST TO WEAKEN BELOW GALE-FORCE THIS AFTERNOON.
HOWEVER...WINDS TO 25 KT AND SEAS OF 8 TO 11 FEET WILL REMAIN
ACROSS THE AREA THROUGH THIS EVENING.

GALE-FORCE WINDS BETWEEN A 1012 MB LOW NEAR 31N77W AND A HIGH
PRESSURE AXIS OVER THE W ATLC ARE FORECAST TO WEAKEN BELOW GALE-
FORCE THIS AFTERNOON AS THE LOW MOVES NORTHWESTWARD.
HOWEVER...WINDS UP TO 30 KT AND SEAS TO 11 FT ARE EXPECTED TO
CONTINUE THROUGH TONIGHT WITHIN A COUPLE HUNDRED NM SE OF THE
LOW.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 9N37W TO 20N40W MOVING W AT 15 TO 20
KT OVER THE PAST 24 HOURS. THE WAVE COINCIDES WITH 700 MB
TROUGHING BETWEEN 36W AND 44W. A MODERATE INCREASE IN MOISTURE N
OF 12N IS INDICATED IN SSMI TPW IMAGERY. SAHARAN DUST IN THE
WAVE ENVIRONMENT IS INHIBITING CONVECTION WITH THIS WAVE.

TROPICAL WAVE EXTENDS FROM 10N70W TO 21N69W MOVING W AT 15 TO 20
KT OVER THE PAST 24 HOURS. THIS WAVE IS AT THE LEADING EDGE OF
AN INCREASE IN MID LEVEL MOISTURE. A 700 MB TROUGH IS NOTED
BETWEEN 66W AND 73W. NO DEEP CONVECTION IS OCCURRING WITH THIS
WAVE.

TROPICAL WAVE IS OVER CENTRAL AMERICA AND THE E PAC. PLEASE
REFER TO THE EASTERN PACIFIC TROPICAL WEATHER DISCUSSION FOR
MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
18N16W TO A 1012 MB LOW NEAR 11N27W TO 9N37W TO 09N47W...WHERE
THE ITCZ BEGINS AND CONTINUES TO 10N60W. CLUSTERS OF MODERATE
AND ISOLATED STRONG CONVECTION ARE FROM 11N TO 16N BETWEEN 16W
AND 22W. WIDELY SCATTERED MODERATE CONVECTION ARE FROM 05N TO
14N BETWEEN 25W AND 41W.

...DISCUSSION...

GULF OF MEXICO...
A MOIST AIRMASS IN NOTED IN SSMI TPW IMAGERY N OF 24N AND E OF
95W OVER THE GULF BASIN TODAY. THIS DEEP MOISTURE SUPPORTS A
BROAD AREA OF CLOUD COVER WITH EMBEDDED WIDELY SCATTERED
MODERATE CONVECTION OVER THIS PORTION OF THE GULF BASIN.
STEERING FLOW IS GENERALLY WEAK ACROSS THE GULF WITH A 1017 MB
HIGH CENTERED NEAR 24N92W SUPPORTING 10 KT E WINDS OVER THE SW
GULF...NW WINDS OF 5 TO 10 KT OVER THE NW GULF...AND NW TO W
WINDS OF 5 TO 10 KT OVER THE EASTERN GULF. THIS MOISTURE AND
ASSOCIATED CONVECTION ARE FORECAST TO PERSIST OVER THE NW GULF
THROUGH SATURDAY.

CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN. PLEASE REFER TO
THE TROPICAL WAVES SECTION FOR MORE DETAILS. DEEP MOISTURE OVER
THE CARIBBEAN IS CONFINED TO THE WESTERN SHORES OF CENTRAL
AMERICA...AND EAST OF THE TROPICAL WAVE. UPPER LEVEL DIFFLUENCE
SUPPORTS CLUSTERS OF MODERATE TO STRONG CONVECTION OVER THE SW
CARIBBEAN FROM 08N TO 13N BETWEEN 80W AND 85W. ADDITIONAL UPPER
LEVEL DIFFLUENCE OVER THE EASTERN CARIBBEAN SUPPORTS ISOLATED
MODERATE CONVECTION FROM SAINT VINCENT TO DOMINICA OVER THE
LESSER ANTILLES. GALE FORCE WINDS OVER THE SW CARIBBEAN WILL
WEAKEN SLIGHTLY THIS AFTERNOON TO UNDER GALE-FORCE. SEE THE
SPECIAL FEATURES SECTION FOR MORE DETAILS. MODERATE TO FRESH
TRADE WINDS ARE MAINLY ELSEWHERE OVER THE CARIBBEAN. OVER THE
NEXT 24 HOURS CONVECTION IS FORECAST TO PERSIST OVER THE SW
CARIBBEAN.

...HISPANIOLA...
A TROPICAL WAVE IS MOVING ACROSS THE ISLAND THIS AFTERNOON.
ISOLATED SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS WAVE
PASSAGE THROUGH TONIGHT. REMNANT MOISTURE BEHIND THIS WAVE WILL
BE SUFFICIENT TO SUPPORT ISOLATED TO SCATTERED AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE ISLAND ON FRIDAY.

ATLANTIC OCEAN...
A 1012 MB LOW CENTERED NEAR 31N77W SUPPORTS A SURFACE TROUGH TO
29N81W. SCATTERED MODERATE CONVECTION ARE WITHIN 250 NM SE OF
THE TROUGH AXIS. A STRONG PRESSURE GRADIENT BETWEEN THE LOWER
PRESSURES ASSOCIATED WITH THESE SURFACE FEATURES AND HIGH
PRESSURE TO THE EAST WAS SUPPORTING GALE FORCE WINDS EARLIER
TODAY. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE
DETAILS. A 1026 MB HIGH CENTERED NEAR 33N32W SUPPORTS GENERALLY
FAIR WEATHER ACROSS THE CENTRAL AND EASTERN SUBTROPICAL ATLC E
OF 67W. A TROPICAL WAVE IS OVER THE TROPICAL ATLC. PLEASE REFER
TO THE TROPICAL WAVES SECTION FOR MORE DETAILS.

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

$$
LATTO



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