[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150554
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE OCT 15 2013

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 06N46W TO 15N40W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH SURFACE TO 700 MB TROUGHING WITH LOW-
LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE WAVE AXIS. IN
ADDITION...MOIST SOUTHWESTERLY DIFFLUENT UPPER LEVEL FLOW IS
HELPING TO SUSTAIN SCATTERED MODERATE CONVECTION FROM 07N-11N
BETWEEN 42W-47W.

TROPICAL WAVE EXTENDS FROM 10N82W TO 20N80W MOVING W AT 15 KT.
THE WAVE LIES BENEATH AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED OVER THE WESTERN CARIBBEAN NEAR 15N82W PROVIDING AN
OVERALL DIFFLUENT ENVIRONMENT. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 09N-17N BETWEEN 74W-84W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N17W TO
11N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
11N18W TO 06N30W TO 08N36W. WIDELY SCATTERED MODERATE CONVECTION
IS FROM 03N-09N BETWEEN 20W-36W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
OVER NE MEXICO NEAR 24N98W THAT IS PROVIDING THE GULF BASIN WITH
GENERALLY DRY AND STABLE FLOW ALOFT THIS EVENING. THIS STABILITY
REFLECTS TO THE SURFACE AS A RIDGE REMAINS IN PLACE EXTENDING SW
FROM THE SE CONUS WITH LIGHT ANTICYCLONIC WINDS IN THE RANGE OF
5 TO 15 KT ACROSS THE BASIN THROUGH THE OVERNIGHT HOURS INTO
TUESDAY. THE SURFACE RIDGING IS EXPECTED TO REMAIN ACROSS THE
GULF THROUGH WEDNESDAY WHEN THE NEXT FRONTAL BOUNDARY IS
FORECAST TO EMERGE OFF THE TEXAS GULF COAST LATE WEDNESDAY.

CARIBBEAN SEA...
MUCH OF THE WESTERN CARIBBEAN IS UNDER THE INFLUENCE OF UPPER
LEVEL DIFFLUENCE IN ASSOCIATION WITH AN UPPER LEVEL RIDGE
EXTENDING FROM 19N86W TO 09N74W. PLENTY OF MOISTURE AND
INSTABILITY...ALONG WITH LOW-LEVEL MOISTURE CONVERGENCE IN THE
VICINITY OF A TROPICAL WAVE ALONG 81W IS GENERATING WIDELY
SCATTERED SHOWERS AND TSTMS THIS EVENING FROM 09N-17N BETWEEN
74W-84W. A FEW ISOLATED SHOWERS ARE ALSO NOTED ACROSS WESTERN
CUBA AS WELL BUT CONTINUE TO DIMINISH. FARTHER EAST...AN UPPER
LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH
ATLC AND DIPS TROUGHING SOUTHWARD TO 16N BETWEEN 68W-80W. EAST
OF THE TROUGH AXIS MIDDLE TO UPPER LEVEL DIFFLUENT IS MAXIMIZED
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 14N-20N
BETWEEN 66W-72W...INCLUDING PORTIONS OF EASTERN HISPANIOLA AND
THE MONA PASSAGE. OTHERWISE...NORTHERLY FLOW ALOFT DOMINATES E
OF 66W AND IS PROVIDING AN OVERALL STABLE ENVIRONMENT ALOFT THIS
EVENING FOR THE LESSER ANTILLES.

HISPANIOLA...
CURRENTLY THE ISLAND FALLS WITHIN MAXIMUM UPPER LEVEL DIFFLUENCE
ALOFT BETWEEN UPPER LEVEL TROUGHING TO THE NORTH OVER THE SW
NORTH ATLC REGION AND AN UPPER LEVEL ANTICYCLONIC CIRCULATION
ANCHORED OVER THE WESTERN AND CENTRAL CARIBBEAN SEA THIS
EVENING. MOISTURE IN PLACE OVER THE REGION CONTINUES TO LIFT
GENERATING CLOUDINESS AND WIDELY SCATTERED SHOWERS AND ISOLATED
TSTMS ACROSS EASTERN PORTIONS OF THE ISLAND AND THE ADJACENT
COASTAL WATERS FROM 16N-21N BETWEEN 67W-72W. THE UPPER LEVEL
TROUGHING IS EXPECTED TO CONTINUE DIGGING SOUTHWARD AND REMAIN
OVER THE ISLAND THROUGH EARLY WEDNESDAY PROVIDING THE INCREASED
PROBABILITY OF SHOWER AND TSTM ACTIVITY THROUGH MID-WEEK.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY
CENTERED NEAR 33N72W THAT EXTENDS TROUGHING SOUTHWARD TO A BASE
NEAR 20N73W OVER THE SW NORTH ATLC. THIS IS SUPPORTING AN
OVERALL WEAK PRESSURE GRADIENT AND LOWER PRESSURE W OF 60W. A
1013 MB IS CENTERED NEAR 32N72W AND EXTENDS SURFACE TROUGHING
NORTHWARD ALONG 72W TO 39N73W. SCATTERED SHOWERS AND ISOLATED
TSTMS ARE OCCURRING PRIMARILY N OF 31N BETWEEN 65W-76W WITH THIS
FEATURE. A WEAK CIRCULATION IS NOTED ALONG A SURFACE TROUGH AXIS
EXTENDING FROM 28N80W TO 31N80W AND IS PRODUCING ISOLATED
SHOWERS N OF 28N W OF 77W THIS EVENING. THIS FEATURE CONTINUES
TO WEAKEN AND WILL EVENTUALLY DISSIPATE DUE TO A LACK OF
FAVORABLE UPPER LEVEL SUPPORT. LASTLY FOR THE REGION...A SURFACE
TROUGH IS ANALYZED FROM THE SE BAHAMAS NEAR 22N74W TO 26N70W AND
REMAINS THE PRIMARY FOCUS FOR SCATTERED SHOWERS AND TSTMS
ASSOCIATED WITH FAVORABLE DYNAMICS EAST OF THE UPPER LEVEL
TROUGH AXIS. LOW-LEVEL MOISTURE CONVERGENCE OCCURRING IN THE
VICINITY OF THE SURFACE TROUGH ALONG WITH MAXIMUM UPPER LEVEL
DIFFLUENCE IS GENERATING A LARGE AREA OF SCATTERED SHOWERS AND
ISOLATED TSTMS FROM 18N-31N BETWEEN 60W-78W. THE UPPER LEVEL
TROUGHING IS FORECAST TO GRADUALLY DRIFT EASTWARD THROUGH
WEDNESDAY WITH MOST OF THE ACTIVE WEATHER ASSOCIATED WITH THE
TROUGHING OCCURRING E OF 70W FOR THE LATTER PART OF THE WEEK.
FARTHER EAST...WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL
TROUGH AXIS EXTENDS FROM 35N38W TO 33N51W THAT SUPPORTS A COLD
FRONT ANALYZED FROM THE AZORES NEAR 38N26W SW TO 30N41W TO
26N60W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 120 NM
EITHER SIDE OF THE BOUNDARY AS IT SLOWLY MOVES EASTWARD.
FINALLY...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC ARE
UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1024 MB
HIGH CENTERED NEAR THE MADEIRA ISLANDS NEAR 33N16W. THE RIDGE
AXIS EXTENDS FROM THE HIGH SOUTHWESTWARD TO 23N50W.

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

$$
HUFFMAN


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