[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT SEP 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.

...TROPICAL WAVES...
A TROPICAL WAVE OVER THE EASTERN ATLC HAS AN AXIS THAT EXTENDS
FROM 17N25W TO 08N27W...MOVING W AT 10 TO 15 KT. SSMI TPW SHOWS
HIGH MOISTURE S OF 15N. A TILTED 700 MB TROUGH EXTENDS FROM NEAR
THE CAPE VERDE ISLANDS TO NEAR 06N29W WHICH INCLUDES THE
ENVIRONMENT OF THE WAVE. SCATTERED MODERATE CONVECTION IS FROM
07N TO 14N BETWEEN 22W AND 30W.

A TROPICAL WAVE OVER THE CENTRAL ATLC HAS AN AXIS THAT EXTENDS
FROM 16N47W TO 08N49W MOVING W AT 15 TO 20 KT. A BROAD 700 MB
TROUGH IS EVIDENT BETWEEN 40W AND 52W. HIGH MOISTURE IS EVIDENT
S OF 15N WITH A POLEWARD SURGE OF MODERATE MOISTURE N OF 15 E OF
THE WAVE. SCATTERED MODERATE CONVECTION IS FROM 07N TO 14N
BETWEEN 45W AND 52W.

A TROPICAL WAVE OVER THE SW N ATLC AND EASTERN CARIBBEAN HAS AN
AXIS THAT EXTENDS FROM 20N67W TO 13N68W MOVING W AT AROUND 15
KT. A SHARP 700 MB TROUGH IS EVIDENT BETWEEN 64W AND 70W.
ISOLATED MODERATE CONVECTION IS FROM 14N TO 22N BETWEEN 61W AND
70W.

A TROPICAL WAVE OVER THE SW CARIBBEAN AND E PACIFIC HAS AN AXIS
THAT EXTENDS FROM 0615N82W TO 06N83W...MOVING W AT 15 TO 20 KT.
A SUBTLE 700 MB TROUGH IS EVIDENT BETWEEN 77W AND 85W. ISOLATED
THUNDERSTORMS ARE S OF 15N BETWEEN 79W AND 85W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N16W TO
10N25W TO 07N34W TO 10N42W. THE INTERTROPICAL CONVERGENCE ZONE
AXIS EXTENDS FROM 10N42W TO 10N46W TO 09N54W. SCATTERED MODERATE
CONVECTION IS FROM 15N-18N BETWEEN 15W-21W AND FROM 05N-10N
BETWEEN 30W-38W. ISOLATED MODERATE CONVECTION IS FROM 08N-14N
BETWEEN 40W-58W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD MID TO UPPER LEVEL TROUGH EXTENDS FROM THE OHIO VALLEY
SW TO THE NW AND N CENTRAL GULF. THIS TROUGH SUPPORTS A COLD
FRONT THAT EXTENDS FROM 31N87W TO 29N92W TO 28N97W. A PAIR OF
PRE-FRONTAL SURFACE TROUGHS ARE S OF THE FRONT AND EXTEND FROM
27N90W TO 24N98W...AND FROM 30N84W TO 27N88W. SCATTERED MODERATE
CONVECTION IS WITHIN 125 NM S OF THE TROUGH AXIS E OF 93W.
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION ARE WITHIN 250
NM S OF THE TROUGH AXIS W OF 93W. N TO NE WINDS AROUND 15 KT ARE
N OF THE COLD FRONT. N TO NW WINDS OF 15 TO 20 KT ARE BETWEEN
THE FRONT AND SURFACE TROUGHS. SW TO SE WINDS OF 10 TO 15 KT ARE
S OF THE TROUGHS. OVER THE NEXT 24 HOURS THE COLD FRONT WILL
MOVE OVER THE CENTRAL GULF. CONVECTION WILL REMAIN LIKELY ALONG
AND WITHIN A COUPLE HUNDRED MILES S OF THE COLD FRONT.

CARIBBEAN SEA...
AN UPPER TROUGH OVER HISPANIOLA AND THE CENTRAL CARIBBEAN IS
INTERACTING WITH A TROPICAL WAVE TO PRODUCE ISOLATED MODERATE
CONVECTION OVER THE NE CARIBBEAN...INCLUDING PUERTO RICO.
ISOLATED THUNDERSTORMS OVER THE SW CARIBBEAN ARE ASSOCIATED WITH
ANOTHER TROPICAL WAVE. PLEASE REFER TO THE TROPICAL WAVES
SECTION FOR MORE DETAILS. GENTLE TO MODERATE TRADE WINDS COVER
THE MAJORITY OF THE CARIBBEAN TODAY...EXCEPT FOR A SMALL AREA OF
MODERATE TO FRESH TRADE WINDS N OF 15N WITHIN 150 NM OF THE AXIS
OF THE TROPICAL WAVE OVER THE EASTERN CARIBBEAN. OVER THE NEXT
24 HOURS EXPECT GUSTY WINDS AND CONVECTION TO SPREAD W ACROSS
PUERTO RICO...HISPANIOLA...AND CARIBBEAN WATERS N OF 15N IN THE
AREA OF THE TROPICAL WAVE OVER THE E CARIBBEAN.

...HISPANIOLA...
MOISTURE WILL INCREASE THROUGH THIS AFTERNOON AND EVENING AS A
TROPICAL WAVE APPROACHES FROM THE WEST. AS THE MOISTURE
ASSOCIATED WITH THE WAVE INTERACTS WITH HIGHER TERRAIN OVERNIGHT
TONIGHT INTO SUNDAY MORNING...HEAVY RAINFALL MAY OCCUR. THIS
COULD RESULT IN FLASH FLOODING AND MUD SLIDES IN THOSE AREAS
PRONE TO THESE HAZARDS.

ATLANTIC OCEAN...
AN UPPER TROUGH OVER THE OHIO VALLEY IS PRODUCING SW FLOW ALOFT
W OF 75W OVER THE SW N ATLC N OF 26N. ASCENT ASSOCIATED WITH
THIS FLOW ALOFT SUPPORTS ISOLATED MODERATE CONVECTION NW OF A
LINE FROM 24N80W TO 20N70W. AN UPPER LOW CENTERED NEAR 30N59W
SUPPORTS ISOLATED MODERATE CONVECTION FROM 27N TO 31N BETWEEN
51W AND 62W. A 1017 MB LOW CENTERED NEAR 28N41W HAS A SURFACE
TROUGH THAT EXTENDS FROM THE LOW CENTER TO 31N39W. ISOLATED
MODERATE CONVECTION IS FROM 28N TO 31N BETWEEN 39W AND 43W. TWO
TROPICAL WAVES ARE OVER THE TROPICAL ATLC. PLEASE REFER TO THE
TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS
CONVECTION WILL INCREASE E OF FL AS THE TROUGH OVER THE OHIO
VALLEY MOVES E AND A COLD FRONT NEARS THE AREA.

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

$$
LATTO
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