[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131152
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT OCT 13 2012

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.

...SPECIAL FEATURES...

TROPICAL STORM RAFAEL IS CENTERED NEAR 15.5N 63.9W AT 13/1200
UTC OR ABOUT 145 NM SSE OF SAINT CROIX MOVING NW AT 8 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED
WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. WIDELY SCATTERED STRONG
AND SCATTERED MODERATE CONVECTION ARE FROM 09N-23N BETWEEN
53W-65W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC.

TROPICAL DEPRESSION PATTY IS CENTERED NEAR 25.5N 71.9W AT
13/0900 UTC OR ABOUT 245 NM ENE OF THE CENTRAL BAHAMAS REMAINING
STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB.
MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT.
SCATTERED MODERATE CONVECTION IS FROM 23N-28N BETWEEN 67W-72W.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 10N31W TO 17N30W MOVING W AT 10 KT.
BROAD AND WEAK CYCLONIC FLOW IS NOTED IN THE VICINITY OF THE
WAVE AXIS AS IT COINCIDES WITH MAXIMUM MOISTURE VALUES IN RECENT
TOTAL PRECIPITABLE WATER IMAGERY FROM 09N-15N BETWEEN 26W-32W.
SCATTERED MODERATE CONVECTION IS FROM 10N-20N BETWEEN 24W-33W
AND REMAINS LIKELY ENHANCED DUE TO UPPER LEVEL DIFFLUENT FLOW
ASSOCIATED WITH AN UPPER LEVEL LOW CENTERED NEAR 22N34W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
11N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
11N18W TO 09N25W TO 10N31W TO 09N44W TO 07N53W. SCATTERED
MODERATE CONVECTION IS FROM 04N-07N BETWEEN 17W-22W. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION IS FROM 03N-10N BETWEEN
23W-30W...AND FROM 06N-12N BETWEEN 33W-46W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL RIDGE IS CENTERED OVER THE WESTERN GULF
PROVIDING NW TO N FLOW ALOFT WITH WATER VAPOR IMAGERY INDICATING
DRY AIR AND SUBSIDENCE DOMINATES. AT THE SURFACE...A RIDGE
INFLUENCES THE ENTIRE GULF BASIN ANCHORED BY A 1033 MB HIGH
CENTERED IN THE NE CONUS NEAR 42N77W. THE RIDGE AXIS EXTENDS
S-SW ALONG THE EAST COAST OF THE U.S. WITH CLEAR SKIES NOTED ON
SATELLITE IMAGERY THIS MORNING...HOWEVER...A FEW ISOLATED
SHOWERS ARE OCCURRING ACROSS PORTIONS OF THE FAR WESTERN GULF S
OF 27N W OF 96W. THE SURFACE RIDGE IS FORECAST TO REMAIN ACROSS
THE BASIN THROUGH THE WEEKEND WITH NE TO E WINDS EXPECTED E OF
90W AND E TO SE WINDS EXPECTED W OF 90W.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH AXIS EXTENDS SOUTHWESTWARD FROM OVER THE
SW NORTH ATLC TO OVER THE NW CARIBBEAN ALONG 22N80W TO 14N85W.
NW OF THE TROUGH AXIS...WATER VAPOR IMAGERY INDICATES VERY DRY
NORTHERLY FLOW WHICH IS PROVIDING FOR OVERALL STABLE CONDITIONS
ACROSS THE NW CARIBBEAN THIS MORNING. EAST OF THE UPPER LEVEL
TROUGH AXIS...A NARROW CORRIDOR OF MIDDLE TO UPPER LEVEL
MOISTURE IS NOTED ON WATER VAPOR IMAGERY EXTENDING FROM 20N75W
TO 14N84W. MID-LEVEL LIFTING DYNAMICS AND LOW-LEVEL MOISTURE
CONVERGENCE IS GENERATING ISOLATED SHOWERS AND TSTMS ACROSS
EASTERN CUBA...THE ADJACENT COASTAL WATERS BETWEEN CUBA AND
JAMAICA...AND AN AREA FROM 13N-18N BETWEEN 78W-84W. ACROSS THE
SW CARIBBEAN...THE MONSOON TROUGH AXIS EXTENDS EASTWARD FROM THE
EASTERN PACIFIC REGION ALONG 10N AND IS PROVIDING FOCUS FOR
ISOLATED SHOWERS AND TSTMS FROM 09N-12N BETWEEN 75W-82W.
FINALLY...TROPICAL STORM RAFAEL IS CENTERED OVER THE EASTERN
CARIBBEAN AND LIES ON THE SE PERIPHERY OF AN UPPER LEVEL LOW
CENTERED NEAR 21N68W. THIS LOW IS PROVIDING A WEAKNESS BETWEEN
TWO MID-LEVEL RIDGES...ONE W OF 78W...THE OTHER E OF 60W...FOR
RAFAEL TO TRACK ON AN OVERALL N-NW TRACK OVER THE NEXT SEVERAL
DAYS. NUMEROUS SHOWERS AND SCATTERED STRONG TSTMS ARE OCCURRING
FROM 09N-23N BETWEEN 53W-65W...INCLUDING THE LESSER ANTILLES...
AND TRINIDAD AND TOBAGO.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS INTO THE DISCUSSION AREA NEAR
32N71W SW TO 22N80W AND INTO THE NW CARIBBEAN SEA. VERY DRY AIR
ALOFT IS ASSOCIATED WITH THIS TROUGH WHICH IS RESULTING IN
MOSTLY FAIR CONDITIONS FOR PORTIONS OF THE SW NORTH ATLC W OF
76W. A FEW ISOLATED LOW-TOPPED SHOWERS ARE HOWEVER OCCURRING
WITHIN 60 NM EITHER SIDE OF A LINE FROM 30N76W TO 25N80W. TO THE
EAST OF THE UPPER LEVEL TROUGH AXIS OVER THE REMAINDER OF THE SW
NORTH ATLC...TROPICAL DEPRESSION PATTY CONTINUES TO ANCHOR A
BROAD AREA OF SURFACE TROUGHING BETWEEN 64W-77W. WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING FROM 20N-26N
BETWEEN 74W-77W TO THE W-SW OF PATTY...WHILE CONVECTION
ASSOCIATED WITH PATTY REMAINS MOSTLY IN THE NORTHEAST AND EAST
QUADRANTS AND CONTINUES TO BE INFLUENCED BY STRONG SOUTHWESTERLY
WIND SHEAR. SCATTERED SHOWERS AND TSTMS COVER THE AREA WITHIN
180 NM EITHER SIDE OF A STATIONARY FRONT FROM 26N71W TO BEYOND
32N64W. SE OF PATTY...CONVECTION FROM TROPICAL STORM RAFAEL
CONTINUES TO IMPACT PORTIONS OF THE ATLC WATERS FROM 10N-24N
BETWEEN 52W-65W. RAFAEL IS FORECAST TO MOVE INTO THE ATLC WATERS
LATE SATURDAY AND CONTINUE ON A N-NW TRACK THROUGH LATE MONDAY.
ELSEWHERE THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER
THE INFLUENCE OF A BROAD SURFACE RIDGE ANCHORED BY A 1027 MB
HIGH CENTERED NEAR 35N38W. EMBEDDED WITHIN THE SURFACE RIDGE...
AN UPPER LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY CENTERED NEAR
22N34W AND IS GENERATING ISOLATED SHOWERS AND TSTMS FROM 21N-24N
BETWEEN 35W-37W.

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

$$
HUFFMAN




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