[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131807 AAA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON JUL 13 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...

SATELLITE IMAGERY AND SCATTEROMETER DATA CONFIRM THAT THE LOW
PRESSURE SYSTEM SEVERAL HUNDRED MILES E OF N CAROLINA HAS
DEVELOPED INTO TROPICAL STORM CLAUDETTE. AS OF 1700 UTC THE
CENTER OF THE TROPICAL STORM WAS NEAR 37.4N 68.1W...MOVING
NORTHEAST AT 13 KT. MAXIMUM SUSTAINED WINDS ARE 45 KT WITH GUSTS
TO 55 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT3/WTNT23 FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLANTIC WITH AN AXIS EXTENDING
FROM 18N22W TO 06N24W...MOVING W AT 10 TO 15 KT. THIS WAVE IS
EVIDENT IN 700 MB MODEL STREAMLINE FIELDS WITH SOUNDINGS
CONFIRMING THE WAVE PASSAGE AT DAKAR LATE SUNDAY...AND NOT YET
ARRIVING AT SENEGAL AS OF 1200 UTC. SSMI TPW IMAGERY INDICATES
MODERATE MOISTURE IS ALONG THE NORTHERN HALF OF THE WAVE WITH
HIGH MOISTURE S OF 10N. SAHARAN DUST IS ALSO NOTED N OF 17N.
ISOLATED MODERATE CONVECTION IS FROM 05N TO 12N BETWEEN 22W AND
26W.

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AN AXIS
EXTENDING FROM 19N38W TO 07N40W...MOVING W AT AROUND 20 KT OVER
THE PAST 24 HOURS. THIS WAVE IS WELL DEFINED BOTH IN THE 70 MB
STREAMLINES OF THE MODEL FIELDS AND IN SATELLITE IMAGERY. SSMI
TPW INDICATE DRY AIR N OF 11N WITH MOIST AIR S OF 11N IN THE
WAVE ENVIRONMENT. ENHANCED METEOSAT IMAGERY INDICATE A
SIGNIFICANT AMOUNT OF SAHARAN DUST EMBEDDED IN THE NORTHERN HALF
OF THE WAVE. ISOLATED MODERATE CONVECTION IS FROM 06N TO 10N
BETWEEN 37W AND 42W.

A TROPICAL WAVE OVER THE WESTERN ATLC AT 1200 UTC HAD AN AXIS
FROM 19N60W TO 07N61W AND IS NOW CROSSING THE LEEWARD ISLANDS AS
OF EARLY THIS AFTERNOON...AS NOTED BY RECENT WIND SHIFT FROM
EAST-NORTHEAST TO SOUTHEAST NEAR GUADELOUPE. THIS WAVE IS AT THE
LEADING EDGE OF A LOW AMPLITUDE SURGE OF HIGH MOISTURE ACCORDING
TO SSMI TPW IMAGERY. 700 MB MODEL STREAMLINES CLEARLY DEPICTS
THIS WAVE AXIS. ISOLATED MODERATE CONVECTION IS FROM 08N TO 12N
BETWEEN 58W AND 62W.

A TROPICAL WAVE EXTENDS ACROSS THE W CARIBBEAN WITH AN AXIS FROM
21N81W TO 09N83W...MOVING W AT 15 TO 20 KT OVER THE PAST 24
HOURS. THE NORTHERN PORTION OF THE WAVE IS INTERACTING WITH A
SURFACE TROUGH AND IS UNDER THE AXIS OF A BROAD UPPER TROUGH.
MODERATE MOISTURE IS N OF 15N WITH HIGH MOISTURE S OF 15N ALONG
THE WAVE. UPPER LEVEL DIFFLUENCE IS INTERACTING WITH THE WAVE
AND MOISTURE TO SUPPORT SCATTERED MODERATE CONVECTION S OF 15N W
OF 77W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N14W TO
09N22W...THEN W OF A TROPICAL WAVE NEAR 08N26W TO 08N37W. THE
ITCZ BEGINS NEAR 07N42W TO 09N59W. SCATTERED MODERATE CONVECTION
IS FROM 03N TO 07N BETWEEN 12W AND 36W...INCLUDING THE EASTERN
ATLC TROPICAL WAVE. ISOLATED MODERATE CONVECTION IS ELSEWHERE
WITHIN 150 NM OF THE MONSOON TROUGH AND ITCZ AXIS.

...DISCUSSION...

GULF OF MEXICO...

A BROAD UPPER RIDGE CENTERED OVER TX EXTENDS ACROSS MOST OF THE
GULF WITH NE WINDS PREVAILING ALOFT. WEAK DISTURBANCES MOVING
AROUND THE PERIPHERY OF THIS RIDGE ARE SUPPORTING CLUSTERS OF
MODERATE CONVECTION OVER THE CENTRAL GULF FROM 24N TO 29N
BETWEEN 85W AND 90W. A 1018 MB HIGH IS CENTERED NEAR 26N92W AND
IS PRODUCING ANTICYCLONIC WINDS BETWEEN 5 AND 15 KT OVER THE
BASIN...EXCEPT NEAR A SURFACE TROUGH THAT EXTENDS FROM 22N92W TO
18N93W WHERE WINDS UP TO 20 KT ARE POSSIBLE. EXPECT LITTLE
CHANGE OVER THE GULF OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...

A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN. A SECOND TROPICAL
WAVE IS ENTERING THE EASTERN CARIBBEAN. PLEASE SEE THE TROPICAL
WAVES SECTION FOR MORE DETAILS. AN UPPER TROUGH EXTENDS FROM THE
WESTERN ATLC SW TO NICARAGUA. UPPER RIDGING IS OVER NORTHERN S
AMERICA. SW FLOW ALOFT IS DRAWING MID TO UPPER LEVEL MOISTURE
ACROSS THE CENTRAL CARIBBEAN WITH SHOWERS LIKELY OCCURRING UNDER
THE BROAD AREA OF CLOUDINESS OVER THIS PORTION OF THE BASIN.
TRADE WINDS OF 5 TO 10 KT COVER THE WESTERN CARIBBEAN...WITH
TRADE WINDS OF 15 TO 20 KT OVER THE CENTRAL AND EASTERN
CARIBBEAN. EXPECT CONVECTION TO CONTINUE OVER THE SW CARIBBEAN
AND SPREADING INTO THE NW CARIBBEAN OVER THE NEXT 24 HOURS.

...HISPANIOLA...

A BROAD UPPER LOW US LIFTING NORTH AND AWAY FROM HISPANIOLA OVER
THE OPEN WATERS OF THE WESTERN ATLC...WHICH IS DECREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS OVER HISPANIOLA TODAY.
ISOLATED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE OVER THE
ISLAND THROUGH TUESDAY IN A MODERATELY MOIST AIRMASS.

ATLANTIC OCEAN...

THREE TROPICAL WAVES ARE OVER THE TROPICAL ATLANTIC. PLEASE
REFER TO THE TROPICAL WAVES SECTION ABOVE FOR MORE INFORMATION.
AN UPPER LEVEL LOW OVER THE SW NORTHERN ATLC HAS SPLIT WITH
CENTERS NEAR 23N78W AND 27N70W. THE CYCLONIC FLOW ALOFT COMBINED
WITH MODERATE MOISTURE SUPPORTS SCATTERED MODERATE CONVECTION FROM
22N TO 30N BETWEEN 66W AND 73W. SCATTERED THUNDERSTORMS ARE FROM
23N TO 31N BETWEEN 73W AND 80W. BROAD RIDGING ANCHORED BY HIGH
PRESSURE CENTERED N OF OUR AREA OF DISCUSSION DOMINATES THE
CENTRAL AND EASTERN SUBTROPICAL ATLC. NEWLY NAMED TROPICAL STORM
CLAUDETTE IS LOCATED SEVERAL HUNDRED MILES E OF NORTH CAROLINA.
PLEASE SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. THE
UPPER LOW WILL OPEN AND MERGE WITH AN UPPER TROUGH OVER THE W
ATLC OVER THE NEXT 24 HOURS WITH ONGOING CONVECTION.

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

$$

LATTO
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