Tropical Weather Discussion
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000
AXNT20 KNHC 231751
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 23 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...
TROPICAL STORM DANNY IS CENTERED NEAR 15.8N 58.1W AT 23/1800 UTC
OR ABOUT 190 NM ESE OF ANTIGUA MOVING W AT 13 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND
SPEED IS 45 KT WITH GUSTS TO 55 KT. NUMEROUS MODERATE TO STRONG
CONVECTION ARE FROM 15N TO 19N BETWEEN 55W AND 59W. SEE LATEST
NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

A BROAD AREA OF LOW PRESSURE CENTERED NEAR 14N35W IS MOVING W AT
AROUND 20 KT. THIS LOW IS ALONG THE WESTERN END OF THE MONSOON
TROUGH WITH SSMI TPW IMAGERY INDICATING DEEP MOISTURE IN THE
VICINITY OF THE LOW. ENVIRONMENTAL CONDITIONS ARE FORECAST TO BE
CONDUCIVE FOR DEVELOPMENT OVER THE COUPLE OF DAYS...AND THERE IS
A HIGH CHANCE FOR THIS SYSTEM TO BECOME A TROPICAL CYCLONE OVER
THE NEXT 48 HOURS.

...TROPICAL WAVES...

A TROPICAL WAVE HAS EMERGED OFF THE COAST OF AFRICA THIS MORNING
AS PER THE 1200 UTC SENEGAL SOUNDING CROSS SECTION. THE WAVE HAS
AN AXIS EXTENDING FROM 17N17W TO 09N17W. SSMI TPW INDICATES DEEP
MOISTURE IN THE ENVIRONMENT OF THIS WAVE. SCATTERED MODERATE
CONVECTION IS FROM 06N TO 17N BETWEEN THE AFRICAN COAST AND 21W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
13N17W...THROUGH A 1009 MB SPECIAL FEATURES LOW CENTERED NEAR
14N35W TO 13N40W. THE ITCZ AXIS EXTENDS FROM 09N37W TO 07N45W TO
08N53W. ASIDE FROM CONVECTION ASSOCIATED WITH THE LOW AND THE
TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS FROM 05N TO 10N
BETWEEN 49W AND 53W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LOW IS OVER THE SW GULF WHILE AN UPPER LEVEL
ANTICYCLONE CENTERED OVER THE W ATLC HAS AN AXIS THAT EXTENDS W
ACROSS THE NE GULF. ASCENT ASSOCIATED WITH THE UPPER LOW AND
UPPER LEVEL DIFFLUENCE S OF THE RIDGE AXIS SUPPORTS SCATTERED
THUNDERSTORMS FROM 23N TO 27N BETWEEN 84W AND 94W. A DIURNAL
SURFACE TROUGH IS OVER THE SW GULF FROM 23N94W TO 18N95W.
SCATTERED SHOWERS ARE WITHIN 50 NM OF THE TROUGH AXIS. A 1017 MB
SURFACE HIGH CENTERED NEAR 28N89W IS A SW EXTENSION OF A LARGER
SURFACE RIDGE THAT EXTENDS ACROSS MUCH OF THE EASTERN US. N
WINDS AROUND 10 KT COVER THE NE GULF. E TO SE WINDS OF 5 TO 10
KT COVER MUCH OF THE REMAINDER OF THE GULF. OVER THE NEXT 24
HOURS SCATTERED THUNDERSTORMS WILL CONTINUE OVER THE SOUTHERN
GULF. A DISTURBANCE MOVING SE ACROSS THE CENTRAL US WILL LIKELY
BRING CONVECTION TO THE NORTHERN GULF BY MONDAY NIGHT.

CARIBBEAN SEA...
GENERALLY FAIR WEATHER COVERS MUCH OF THE CARIBBEAN SEA TODAY.
THE ONLY EXCEPTIONS ARE ISOLATED THUNDERSTORMS FROM 20N TO 22N
BETWEEN 81W AND 84W SUPPORTED BY UPPER LEVEL DIFFLUENCE BETWEEN
UPPER LEVEL RIDGING OVER THE W ATLC AND UPPER LEVEL RIDGING OVER
THE SW CARIBBEAN. ISOLATED THUNDERSTORMS ARE ALSO OVER THE SW
CARIBBEAN ASSOCIATED WITH DEEP TROPICAL MOISTURE AND THE NEARBY
E PACIFIC MONSOON TROUGH. GENTLE TO MODERATE TRADE WINDS ARE N
OF 17N OVER THE CARIBBEAN. MAINLY MODERATE TO FRESH TRADE WINDS
ARE OVER THE CARIBBEAN S OF 17N. OVER THE NEXT 24 HOURS WINDS
AND CONVECTION WILL INCREASE OVER THE NORTHERN LESSER ANTILLES
AND VIRGIN ISLANDS AS TROPICAL STORM DANNY APPROACHES THE AREA.

...HISPANIOLA...
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON AND EVENING DUE TO DAYTIME HEATING AND THE PRESENCE OF
SHALLOW MOISTURE. GENERALLY FAIR CONDITIONS ARE EXPECTED TONIGHT
AND MONDAY. TROPICAL STORM DANNY IS FORECAST TO WEAKEN TO A
TROPICAL DEPRESSION AS IT APPROACHES THE ISLAND ON TUESDAY.

ATLANTIC OCEAN...
AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 28N77W OVER THE W
ATLC WHILE AN UPPER LOW IS CENTERED NEAR 31N65W. THE UPPER LOW
SUPPORTS A SURFACE TROUGH THAT EXTENDS S INTO OUR AREA OF
DISCUSSION NEAR 31N62W TO A 1012 MB SURFACE LOW NEAR 25N71W TO
24N75W. SCATTERED SHOWERS ARE WITHIN 160 NM SE OF THE TROUGH W
OF 66W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM NW AND 130
NM SE OF THE SURFACE TROUGH E OF 66W. FARTHER EAST...AN UPPER
LOW CENTERED NEAR 31N45W SUPPORTS ISOLATED MODERATE CONVECTION
WITHIN 180 NM OF THE LOW CENTER. TROPICAL STORM DANNY AND A 1009
MB LOW ARE OVER THE CENTRAL ATLC. PLEASE REFER TO THE SPECIAL
FEATURES SECTION FOR MORE DETAILS. A TROPICAL WAVE HAS JUST
EMERGED OFF THE COAST OF AFRICA. PLEASE REFER TO THE TROPICAL
WAVES SECTION FOR MORE DETAILS CONVECTION WILL CONTINUE OVER THE
CENTRAL SUBTROPICAL ATLC NEAR THE UPPER LOWS OVER THE NEXT 24
HOURS.

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

$$
LATTO



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