[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 09N29W TO 16N26W MOVING W AT 10 KT.
THE WAVE COINCIDES WITH LOW AMPLITUDE 700 MB TROUGHING S OF 15N
BETWEEN 25W-32W. SCATTERED MODERATE CONVECTION REMAINS CONFINED
TO THE MONSOON TROUGH REGION DUE TO SAHARAN DUE ON THE NORTHERN
PERIPHERY OF THE WAVE AXIS FROM 07N-14N BETWEEN 24W-32W.

TROPICAL WAVE EXTENDS FROM 09N52W TO 16N51W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH A BROAD 700 MB TROUGHING BETWEEN 45W-
55W. ISOLATED MODERATE CONVECTION IS FROM 14N-16N BETWEEN 46W-
51W.

TROPICAL WAVE EXTENDS FROM 12N71W TO 19N71W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH A 700 MB TROUGHING BETWEEN 68W-74W AND A
850 MB RELATIVE VORTICITY MAXIMUM OVER HISPANIOLA NEAR 19N72W.
ISOLATED MODERATE CONVECTION IS FROM 16N-20N BETWEEN 66W-74W.

TROPICAL WAVE EXTENDS FROM 08N85W TO 15N85W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH SUBTLE 700 MB TROUGHING OVER CENTRAL
AMERICA BETWEEN 83W-87W. WIDELY SCATTERED MODERATE CONVECTION IS
FROM 08N-16N BETWEEN 80W-89W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 16N16W TO
09N29W TO 10N49W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 09N-15N BETWEEN 12W-17W AND FROM 06N-12N
BETWEEN 38W-45W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM
06N-13N BETWEEN 31W-47W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 13/0300 UTC...LONGWAVE TROUGHING IS NOTED ON WATER VAPOR
IMAGERY OVER MUCH OF THE EASTERN CONUS SUPPORTING A COLD FRONT
EXTENDING FROM THE FLORIDA PANHANDLE SW TO THE TEXAS COAST NEAR
CORPUS CHRISTI. WHILE THIS REMAINS THE PRIMARY BOUNDARY...A PRE-
FRONTAL TROUGH EXTENDS FROM THE FLORIDA BIG BEND REGION SW TO
27N86W WHERE THE LOW PRESSURE VALUES ARE CURRENTLY ANALYZED. AS
SURFACE RIDGING HAS BUILT IN ACROSS SOUTHERN TEXAS AND EASTERN
MEXICO...ANOTHER SURFACE TROUGH IS ANALYZED OFFSHORE OF THE
MEXICO COAST FROM 26N97W TO 21N96W. MOST OF THE LOW-LEVEL
MOISTURE CONVERGENCE...CLOUDINESS...AND ONGOING SCATTERED
SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 300 NM SOUTHEAST
OF THE COLD FRONT. OTHERWISE...GENERALLY GENTLE TO MODERATE NE
FLOW PREVAILS NORTH OF THE COLD FRONT AND RELATIVELY VARIABLE
GENTLE TO MODERATE BREEZE CONDITIONS IN THE FRONTAL TROUGH ZONE
AND ACROSS THE SE GULF. THE MAJORITY OF THE FRONT WILL SLIDE
INTO THE SW NORTH ATLC REGION BY MONDAY WITH A DIFFUSE BOUNDARY
EXTENDING ALONG 25N/26N THAT WILL GRADUALLY LIFT NORTH THROUGH
TUESDAY.

CARIBBEAN SEA...
GENERALLY NORTHERLY FLOW ALOFT PREVAILS OVER MUCH OF THE WESTERN
CARIBBEAN THIS EVENING BETWEEN AN UPPER LEVEL RIDGE ANCHORED
OVER CENTRAL MEXICO AND AN UPPER LEVEL LOW CENTERED NEAR 17N69W.
MOSTLY CLEAR SKIES AND FAIR CONDITIONS ARE NOTED ACROSS THE NW
CARIBBEAN...HOWEVER THE PRESENCE OF A TROPICAL WAVE ALONG 85W
IMPACTING CENTRAL AMERICA IS GENERATING SCATTERED SHOWERS AND
TSTMS S OF 17N BETWEEN 80W-89W. THE WAVE IS EXPECTED TO CONTINUE
WESTWARD ON SUNDAY WITH PRECIPITATION AND CONVECTION PERSISTING
ACROSS COSTA RICA...NICARAGUA...HONDURAS...EL SALVADOR...AND
GUATEMALA UNTIL THE WAVE FULLY ENTERS THE EAST PACIFIC REGION.
FARTHER EAST...A TROPICAL WAVE ALONG 72W IS INTERACTING WITH THE
UPPER LEVEL LOW PREVIOUSLY MENTIONED AND CONTINUES TO GENERATE
ISOLATED SHOWERS AND TSTMS FROM 15N-21N BETWEEN 64W-70W...AND
ACROSS WESTERN HISPANIOLA INCLUDING THE ADJACENT COASTAL WATERS.
LOW-LEVEL MOISTURE AND POSSIBLE ISOLATED SHOWERS STRETCH SE
ACROSS THE LESSER ANTILLES AND INTO THE TROPICAL CENTRAL ATLC.
OTHERWISE...MODERATE TO FRESH TRADES PREVAIL AND ARE EXPECTED TO
INCREASE SLIGHTLY ACROSS THE CENTRAL CARIBBEAN WITH THE
APPROACHING TROPICAL WAVE ON SUNDAY INTO MONDAY.

...HISPANIOLA...
CURRENTLY ISOLATED SHOWERS AND TSTMS ARE APPROACHING THE ISLAND
FROM THE EAST IN ASSOCIATION WITH A TROPICAL WAVE ALONG 72W. THE
OVERALL INCREASE IN MOISTURE AND CLOUDINESS WILL CONTINUE TO
PROVIDE A HIGHER PROBABILITY OF PRECIPITATION ON SUNDAY AS THE
WAVE CONTINUES TO MOVE WEST OF THE ISLAND BY LATE SUNDAY.

ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL ENERGY ASSOCIATED WITH LONGWAVE TROUGHING
OVER THE EASTERN CONUS IS SUPPORTING A FRONTAL BOUNDARY ANALYZED
ALONG THE EASTERN COAST AND FLORIDA PANHANDLE. PRE-FRONTAL
SURFACE TROUGHING ALSO EXTENDS FROM 32N78W SW TO THE CENTRAL AND
SOUTHERN FLORIDA PENINSULA PROVIDING FOCUS FOR SCATTERED SHOWERS
AND TSTMS GENERALLY N OF 26N W OF 72W. OTHERWISE...THE REMAINDER
OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING
WITH AXIS EXTENDING FROM 28N59W SW TO THE CENTRAL CUBA COAST
NEAR 23N79W. OTHERWISE...THE REMAINDER OF THE CENTRAL AND
EASTERN ATLC IS DOMINATED BY BROAD SURFACE RIDGING ANCHORED BY A
1027 MB HIGH CENTERED EAST OF THE AZORES NEAR 39N38W. A WEAK
1016 MB LOW IS EMBEDDED WITHIN THE SOUTHERN PERIPHERY OF THE
RIDGE CENTERED NEAR 29N43W THAT CONTINUES TO GENERATE AN AREA OF
SCATTERED SHOWERS AND ISOLATED TSTMS FROM 29N-32N BETWEEN 41W-
44W.

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

$$
HUFFMAN
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