[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN OCT 04 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
1630 UTC.

...SPECIAL FEATURES...

HURRICANE JOAQUIN CENTERED NEAR 31.6N 66.6W AT 04/1800 UTC OR
109 NM SW OF BERMUDA MOVING NNE AT 13 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 957 MB. MAXIMUM SUSTAINED WIND SPEED IS 90
KT WITH GUSTS TO 110 KT. NUMEROUS MODERATE AND SCATTERED STRONG
CONVECTION IS WITHIN 150 NM IN THE NE SEMICIRCLE AND 45 NM IN
THE SW SEMICIRCLE. SCATTERED MODERATE CONVECTION IS ELSEWHERE
WITHIN 360 NM IN THE NE SEMICIRCLE. A TROUGH IS SE OF THE
HURRICANE FROM 27N65W TO 24N68W TO 21N74W WITH SCATTERED
MODERATE CONVECTION WITHIN 30-60 NM E OF THE TROUGH AXIS.
JOAQUIN IS FORECAST TO WEAKEN WHILE MOVING TO 34.8N 64.8W BY 24
HOURS...THEN TO 36.6N 62.7W BY 48 HOURS. SEE LATEST INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC
AND THE LATEST FULL NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A PAIR OF TROPICAL WAVES OVER THE E CENTRAL ATLC HAVE MERGED
THIS MORNING WITH THE PRIMARY AXIS EXTENDING FROM 20N35W TO LOW
PRES NEAR 10.5N38W 1010 MB. PLENTIFUL CONVECTION IS PRESENT WITH
THESE FEATURES WITH SCATTERED MODERATE FROM 07N-15N BETWEEN 31W-
44W...AND FROM 14N-18N BETWEEN 30W-35W. RECENT SCATTEROMETER
PASSES MISSED THE TROPICAL WAVE AND LOW...HOWEVER A RECENT
ALTIMETER PASS DID MEASURE SEAS TO 8 FT IN THE SE QUADRANT OF
THE LOW. ACCORDING TO THE LATEST GLOBAL MODEL GUIDANCE...THE LOW
IS FORECAST TO MOVE TO NEAR 14N43W WHILE WEAKENING BY 24 HOURS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM NEAR 08N24W TO 14N33W TO
LOW PRES NEAR 10.5N38W 1010 MB TO 09N49W. THE ITCZ AXIS EXTENDS
FROM 09N49W TO 08N59W. ASIDE FROM CONVECTION OCCURRING IN
ASSOCIATION WITH THE LOW AND AN ACCOMPANYING TROPICAL WAVE...
SCATTERED MODERATE CONVECTION IS FROM 05N-08N BETWEEN 29W-34W...
FROM 10N-13N BETWEEN 47W-51W...AND FROM 08N-10N BETWEEN 50W-53W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONE PREVAILS ACROSS THE SW GULF OF MEXICO
NEAR 21N96W. VERY DRY AND STABLE AIR COVERS THE MAJORITY OF THE
GULF S OF 26N. A COMPLEX UPPER LEVEL LOW IS LOCATED OVER
SOUTHERN GEORGIA NEAR THE NORTHERN FLORIDA BORDER NEAR 31N83W.
A SERIES OF TROUGHS CONTINUE TO ROTATE AROUND THIS UPPER LOW...
BOTH ALOFT AND AT THE SURFACE...WITH ISOLATED TO SCATTERED
SHOWERS ACCOMPANYING EACH TROUGH. GENTLE TO MODERATE WINDS WILL
PREVAIL THROUGH THE NEXT 48 HOURS...EXCEPT IN THE NE GULF WHERE
THEY WILL OCCASIONALLY INCREASE TO MODERATE TO FRESH WITH EARLY
SEASON COLD AIR ADVECTION IN PLACE. SEAS WILL BE 1-3 FT ACROSS
THE SW HALF OF THE GULF AND 3-5 FT ACROSS THE NE HALF OF THE
GULF.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH IS MOVING THROUGH THE NW CARIBBEAN FROM
CENTRAL CUBA TO THE GULF OF HONDURAS SUPPORTING A SURFACE TROUGH
WHICH EXTENDS FROM NEAR THE WINDWARD PASSAGE TO NE HONDURAS. NO
SIGNIFICANT CONVECTION IS OBSERVED NEAR THE TROUGH EXCEPT FOR
SOME ISOLATED TSTMS NEAR THE WINDWARD PASSAGE. AN UPPER LEVEL
ANTICYCLONE IS LOCATED IN THE SW CARIBBEAN NEAR 12N79W. STRONG
UPPER LEVEL NORTHERLY FLOW COVERS THE BASIN E OF 72W. THE
SURFACE TROUGH WILL SLIDE TO THE E DURING THE NEXT 24 HOURS
GRADUALLY LOSING DEFINITION. LIGHT TO MODERATE WINDS WILL
PREVAIL ACROSS THE BASIN EXCEPT IN THE S CENTRAL WATERS WHERE
WINDS WILL BE MODERATE TO FRESH...INCREASING TO FRESH TO STRONG
LATE MON NIGHT INTO TUE MORNING. SEAS WILL BE 1-3 FT ACROSS THE
NW CARIBBEAN...WITH 4-7 FT ELSEWHERE EXCEPT BUILDING TO 7-9 FT
IN THE S CENTRAL WATERS.

...HISPANIOLA...
WESTERLY FLOW ASSOCIATED WITH THE CIRCULATION OF JOAQUIN WILL
CONTINUE TO BRING ISOLATED SHOWERS AND THE OCCASIONAL ISOLATED
TSTM ACROSS THE ISLAND. A SURFACE TROUGH TO THE W OF THE ISLAND
WILL APPROACH THE AREA OVER THE NEXT 12-24 HOURS SUPPORTING
ADDITIONAL CONVECTION.

ATLANTIC OCEAN...
HURRICANE JOAQUIN CONTINUES TO DOMINATE MUCH OF THE CONDITIONS
ACROSS THE SW N ATLC. PLEASE REFER TO THE SPECIAL FEATURES
SECTION FOR ADDITIONAL DETAILS ON JOAQUIN. A SURFACE TROUGH
EXTENDS FROM 1001 MB LOW PRES LOCATED OFFSHORE OF THE SOUTH
CAROLINA LOW COUNTRY NEAR 32N79W TO THE SE TO NEAR 28N73W.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING NEAR THE
TROUGH. ADDITIONAL WEAK TROUGHS ARE FORECAST TO ROTATE THROUGH
THE BASIN DURING THE NEXT 24-48 HOURS AROUND AN UPPER LEVEL LOW
THAT IS CURRENTLY NEAR THE SOUTHERN GEORGIA/NORTHERN FLORIDA
BORDER NEAR 31N83W. OVER THE NEXT 24-48 HOURS...THE CIRCULATION
OF JOAQUIN WILL PULL AWAY FROM THE DISCUSSION WATERS WITH
DECREASING INFLUENCES ON THE SW N ATLC.

TO THE E OF 60W...1008 MB LOW PRES IS NEAR 27N53W WITH AN
ELONGATED SURFACE TROUGH REACHING FROM 31N59W TO THE LOW TO
25N43W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING
WITHIN 180 NM IN THE SW QUADRANT OF THE LOW. RECENT
SCATTEROMETER DATA SHOWED FRESH TO STRONG WINDS ON EITHER SIDE
OF THE LOW/TROUGH. THE LOW IS FORECAST TO MOVE ENE AROUND 10 KT
DURING THE NEXT 24-48 HOURS. WEAK 1017 MB HIGH PRES IS LOCATED S-
SW OF THE LOW NEAR 21N55W AS INDICATED BY RECENT SCATTEROMETER
DATA. A DISSIPATING COLD FRONT IS LOCATED OVER THE NE WATERS
FROM NEAR 32N14W TO 21N33W. A SURFACE RIDGE IS BUILDING IN
BEHIND THE FRONT ACCOMPANYING 1019 MB HIGH PRES NEAR 25N29W.

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

$$
LEWITSKY
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