[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 151201
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 08N45W TO 16N39W MOVING W AT 5 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-12N
BETWEEN 43W-48W...AND ISOLATED MODERATE CONVECTION WITHIN 90 NM
EITHER SIDE OF THE AXIS N OF 12N.

TROPICAL WAVE EXTENDS FROM 10N83W TO 18N82W MOVING W AT 10 KT.
THE WAVE LIES BENEATH AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED OVER THE WESTERN CARIBBEAN NEAR 12N80W PROVIDING AN
OVERALL DIFFLUENT ENVIRONMENT. ISOLATED MODERATE CONVECTION IS
FROM 11N-16N BETWEEN 81W-85W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO
12N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
12N19W TO 05N31W TO 06N37W. SCATTERED MODERATE CONVECTION IS
FROM 03N-09N BETWEEN 24W-37W. ISOLATED MODERATE CONVECTION IS
FROM 06N-09N BETWEEN 09W-14W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
OVER THE WESTERN GULF NEAR 24N92W THAT IS PROVIDING THE BASIN
WITH GENERALLY DRY AND STABLE FLOW ALOFT THIS MORNING. 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 FORECAST ACROSS THE BASIN THROUGH LATE
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.

CARIBBEAN SEA...
MUCH OF THE WESTERN CARIBBEAN IS UNDER THE INFLUENCE OF UPPER
LEVEL DIFFLUENCE IN ASSOCIATION WITH AN UPPER LEVEL RIDGE AXIS
EXTENDING FROM 20N88W TO 10N80W TO 08N70W. PLENTY OF MOISTURE
AND INSTABILITY...ALONG WITH LOW-LEVEL MOISTURE CONVERGENCE IN
THE VICINITY OF A TROPICAL WAVE ALONG 83W IS GENERATING WIDELY
SCATTERED SHOWERS AND TSTMS THIS MORNING FROM 08N-16N BETWEEN
73W-85W. FARTHER EAST...AN UPPER LEVEL TROUGH IS NOTED ON WATER
VAPOR IMAGERY OVER THE SW NORTH ATLC AND DIPS TROUGHING
SOUTHWARD TO 15N BETWEEN 67W-80W. EAST OF THE TROUGH AXIS MIDDLE
TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED GENERATING SCATTERED
SHOWERS AND ISOLATED TSTMS FROM 13N-20N BETWEEN 67W-72W...AND
FROM 18N-22N BETWEEN 73W-79W...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. LOW-
LEVEL MOISTURE IS HOWEVER ON THE INCREASE ACROSS THE WINDWARD
ISLANDS WITH A FEW ISOLATED SHOWERS POSSIBLE THROUGH THE MORNING
HOURS AS A SURFACE TROUGH ANALYZED ACROSS THE TROPICAL ATLC
DRIFTS WESTWARD SLOWLY.

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
MORNING. 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 15N-20N 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 33N71W THAT EXTENDS TROUGHING SOUTHWARD TO A BASE
OVER THE NORTH-CENTRAL CARIBBEAN SEA. THIS IS SUPPORTING AN
OVERALL WEAK PRESSURE GRADIENT AND OVERALL LOWER PRESSURE AREA W
OF 60W. A 1012 MB LOW IS CENTERED NEAR 33N73W AND EXTENDS
SURFACE TROUGHING NORTHWARD ALONG 73W TO 39N73W. SCATTERED
SHOWERS AND ISOLATED TSTMS ARE OCCURRING PRIMARILY N OF 31N
BETWEEN 67W-77W WITH THIS FEATURE. A WEAK 1013 MB LOW IS ALSO
NOTED ON SATELLITE IMAGERY PRODUCING ISOLATED SHOWERS N OF 29N W
OF 78W THIS MORNING. LASTLY FOR THE REGION...TWO SURFACE TROUGHS
ARE ANALYZED FROM THE SE BAHAMAS NEAR 23N75W TO 29N68W AND FROM
22N79W TO 27N78W. BOTH BOUNDARIES REMAIN THE FOCUS FOR SCATTERED
SHOWERS AND ISOLATED TSTMS ASSOCIATED WITH FAVORABLE DYNAMICS
EAST OF THE UPPER LEVEL TROUGH AXIS. LOW-LEVEL MOISTURE
CONVERGENCE OCCURRING IN THE VICINITY OF THE SURFACE TROUGHS
ALONG WITH MAXIMUM UPPER LEVEL DIFFLUENCE IS GENERATING A LARGE
AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS FROM 20N-32N
BETWEEN 60W-72W...AND FROM 21N-27N BETWEEN 72W-79W. 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 36N34W TO 31N49W THAT SUPPORTS A COLD
FRONT ANALYZED FROM THE AZORES NEAR 38N25W SW TO 30N40W TO
28N50W. A STATIONARY FRONT EXTENDS FARTHER WEST FROM 28N50W TO
28N60W. WIDELY SCATTERED SHOWERS AND TSTMS ARE OCCURRING WITHIN
120 NM EITHER SIDE OF BOTH FRONTS AS THE COLD FRONT SLOWLY MOVES
EASTWARD. TO THE SOUTH OF THE STATIONARY FRONT...AN UPPER LEVEL
LOW IS NOTED ON WATER VAPOR IMAGERY CENTERED NEAR 18N55W. A
SURFACE TROUGH AXIS RESULTS AT THE SURFACE EXTENDING FROM 12N58W
TO 21N50W WITH ISOLATED SHOWERS AND TSTMS OCCURRING WITHIN 150
NM EITHER SIDE OF A LINE FROM 11N60W TO 20N48W. 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 33N15W. THE RIDGE AXIS EXTENDS
FROM THE HIGH SOUTHWESTWARD TO 22N45W.

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

$$
HUFFMAN

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