[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040555
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI OCT 04 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.

...SPECIAL FEATURES...
TROPICAL STORM KAREN IS CENTERED NEAR 24.5N 89.5W AT 04/0600 UTC
OR ABOUT 280 NM S OF THE MOUTH OF THE MISSISSIPPI RIVER MOVING
NNW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB.
MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT.
SCATTERED MODERATE CONVECTION IS FROM 23N-27N BETWEEN 84W-89W.
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 FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 11N47W TO 17N46W MOVING W AT 15 KT.
THE WAVE REMAINS EMBEDDED WITHIN WEAK SURFACE TO 700 MB
TROUGHING WITH A 700 MB RELATIVE VORTICITY MAXIMUM NOTED ALONG
THE WAVE AXIS NEAR 15N. WIDELY SCATTERED MODERATE CONVECTION IS
FROM 12N-17N BETWEEN 43W-48W.

TROPICAL WAVE EXTENDS FROM 11N55W TO 19N54W MOVING W-NW AT 10
KT. THE WAVE CONTINUES TO SLOW IN SPEED AND STRETCH NORTHWARD AS
THE SURFACE TO 700 MB TROUGHING BROADENS BETWEEN 50W-60W. WITH
SOUTHWESTERLY WIND SHEAR ALOFT TO THE NW OF THE WAVE AXIS...
CONVECTION REMAINS LIMITED AT THIS TIME WITH ONLY ISOLATED
MODERATE CONVECTION OCCURRING FROM 10N-14N BETWEEN 51W-55W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N16W TO
07N27W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N27W TO 06N36W TO 09N54W. ASIDE FROM CONVECTION ASSOCIATED
WITH THE TROPICAL WAVES ACROSS THE EASTERN TROPICAL ATLC...
SCATTERED MODERATE CONVECTION IS FROM 06N-15N BETWEEN 13W-18W.

...DISCUSSION...

GULF OF MEXICO...
THE PRIMARY CONCERN FOR THE GULF THIS EVENING IS TROPICAL STORM
KAREN WHICH IS FORECAST TO TRACK NNW TOWARD THE MOUTH OF THE
MISSISSIPPI RIVER BY LATE SATURDAY. KAREN REMAINS ON THE
NORTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED OVER THE NW CARIBBEAN SEA NEAR 20N86W. WITH A FAVORABLE
UPPER LEVEL DIFFLUENT ENVIRONMENT IN THE VICINITY OF THE CYCLONE
AND AREAS TO THE EAST...PLENTY OF MIDDLE TO UPPER LEVEL MOISTURE
IS NOTED ON SATELLITE IMAGERY E OF 92W. ASIDE FROM KAREN'S CORE
CONVECTION OF SCATTERED SHOWERS AND TSTMS FROM 23N-27N BETWEEN
84W-89W...ISOLATED SHOWERS AND TSTMS ARE OCCURRING ELSEWHERE
FROM 21N-31N BETWEEN 83W-91W. ACROSS THE WESTERN GULF W OF
92W...MOSTLY CLEAR SKIES AND FAIR CONDITIONS PERSIST DUE TO A
RELATIVELY DRY AND STABLE ENVIRONMENT ALOFT FOCUSED IN THE
VICINITY OF A WEAK UPPER LEVEL LOW CENTERED NEAR 24N96W. LOOKING
AHEAD...AS KAREN IS EXPECTED TO MAKE LANDFALL DURING THE
UPCOMING WEEKEND...A COLD FRONT IS FORECAST TO EMERGE OFF THE
TEXAS AND LOUISIANA COAST LATE SATURDAY INTO SUNDAY USHERING IN
NORTHERLY WINDS IN THE RANGE OF 15 TO 25 KT AND SURFACE RIDGING
EXPECTED TO BUILD IN ACROSS THE WESTERN GULF THROUGH EARLY NEXT
WEEK.

CARIBBEAN SEA...
MUCH OF THE WESTERN CARIBBEAN W OF 72W IS UNDER THE INFLUENCE OF
AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 20N86W PROVIDING THIS
AREA WITH NORTHEASTERLY TO EASTERLY FLOW ALOFT. WATER VAPOR
IMAGERY INDICATES THE AIRMASS REMAINS RELATIVELY DRY...HOWEVER
MIDDLE TO UPPER LEVEL CLOUDINESS...PARTIAL OUTFLOW MOISTURE FROM
TROPICAL STORM KAREN CENTERED IN THE GULF OF MEXICO...FANS OVER
THE AREA N OF 15N W OF 78W. A FEW ISOLATED SHOWERS AND TSTMS ARE
OCCURRING WITHIN THIS AREA PRIMARILY OFF THE SOUTHERN COAST OF
CUBA AND IN THE VICINITY OF THE CAYMAN ISLANDS FROM 18N-22N
BETWEEN 78W-82W. TO THE SOUTH ACROSS THE SW CARIBBEAN...
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING S OF 12N...
INCLUDING INLAND PORTIONS OF NORTHERN COLOMBIA...PANAMA...AND
COSTA RICA. THIS PARTICULAR CONVECTION IS LIKELY DUE TO LOW-
LEVEL MOISTURE CONVERGENCE AND THE CLOSE PROXIMITY OF THE
MONSOON TROUGH AXIS ANALYZED ALONG 10N. E OF 72W...UPPER LEVEL
FLOW REMAINS ANTICYCLONIC...HOWEVER IS MOIST SOUTH-SOUTHWESTERLY
FLOW ALOFT. WATER VAPOR IMAGERY ALSO SHOWS THIS AIRMASS TO BE
RELATIVELY DRY ALOFT WITH ONLY A FEW PASSING MIDDLE TO UPPER
LEVEL CLOUDS E OF 68W. AT THE SURFACE...E-SE TRADES PERSIST WITH
ISOLATED LOW-TOPPED SHOWERS EMBEDDED WITHIN E OF 70W.

HISPANIOLA...
CURRENTLY HISPANIOLA IS BENEATH THE BASE OF AN UPPER LEVEL LOW
CENTERED OVER THE SW NORTH ATLC NEAR 25N67W. SATELLITE IMAGERY
INDICATES LOW-LEVEL MOISTURE INCREASES TO THE NORTH OF 20N WITH
ENHANCEMENT OF ISOLATED SHOWERS DUE TO THE MARGINAL UPPER LEVEL
DYNAMICS ASSOCIATED WITH THE UPPER LEVEL LOW. A FEW ISOLATED
SHOWERS CONTINUE TO LINGER ACROSS THE ISLAND THIS EVENING WITH E-
SE TRADES CONTINUING TO USHER IN LOW-LEVEL MOISTURE AND A HIGHER
PROBABILITY OF A PASSING ISOLATED SHOWER DURING THE OVERNIGHT
PERIOD.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL RIDGE ANCHORED OVER THE NW CARIBBEAN SEA
CONTINUES TO PROVIDE DRY NORTHERLY FLOW ALOFT W OF 70W FOR
PORTIONS OF THE SW NORTH ATLC THIS EVENING. WHILE ONLY A FEW
UPPER LEVEL CLOUDS ARE NOTED OVER THIS AREA...AT THE SURFACE...
RIDGING DOMINATES ANCHORED BY A 1022 MB HIGH CENTERED OFF THE
CAROLINA COAST NEAR 34N71W. TO THE EAST OF 70W OVER THE
REMAINDER OF THE SW NORTH ATLC...WATER VAPOR IMAGERY INDICATES
AN UPPER LEVEL LOW CENTERED NEAR 25N71W THAT IS PROVIDING AMPLE
LIFT OF LOW-LEVEL MOISTURE TO INCREASE CLOUDINESS AND GENERATE
ISOLATED SHOWERS FROM 18N-29N BETWEEN 62W-72W. ACROSS THE
CENTRAL ATLC...AN UPPER LEVEL TROUGH AXIS DIPS INTO THE
DISCUSSION AREA NEAR 32N49W SW TO 28N55W THAT SUPPORTS A COLD
FRONT ANALYZED FROM 35N47W TO 31N52W AND A PRE-FRONTAL SURFACE
TROUGH FROM 28N52W TO 32N45W. ISOLATED SHOWERS ARE OCCURRING
WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. TO THE
EAST OF THESE FEATURES...AND QUICKLY BECOMING EMBEDDED WITHIN
THE FRONTAL TROUGHING N OF 30N...THE REMNANT 1012 MB LOW OF
JERRY IS CENTERED NEAR 32N38W. SCATTERED SHOWERS AND TSTMS ARE
OCCURRING PRIMARILY TO THE EAST OF THE LOW CENTER FROM 31N-34N
BETWEEN 32W-38W. THE FRONTAL TROUGHING STRETCHES SOUTH-SOUTHWEST
OF THE REMNANT LOW REMAINING BROAD...BUT LOCATED IN THE VICINITY
OF A SURFACE TROUGH ANALYZED FROM 21N42W TO 26N41W. WIDELY
SCATTERED SHOWERS AND TSTMS ARE OCCURRING EAST OF THE AXIS FROM
21N-28N BETWEEN 36W-41W. OTHERWISE THE REMAINDER OF THE EASTERN
ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A
PAIR OF 1020 MB HIGHS CENTERED NEAR 26N29W AND 34N29W.

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

$$
HUFFMAN


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