[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 101755
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT SEP 10 2011

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
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM NATE IS CENTERED NEAR 20.1N 94.2W AT 10/1800 UTC
OR 125 NM TO THE E-NE OF VERACRUZ MEXICO AND 185 NM E-SE OF
TUXPAN MEXICO MOVING W AT 2 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH
GUSTS TO 60 KT. WIDELY SCATTERED MODERATE CONVECTION IS FROM 17N
TO 22N BETWEEN 92W AND 97W WITH AN OUTER BAND OF SCATTERED
MODERATE CONVECTION EXTENDING WITHIN 60 NM EITHER SIDE OF A LINE
FROM 25N91W TO 22N96W. SEE LATEST NHC INTERMEDIATE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE
FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25
KNHC FOR MORE DETAILS.

TROPICAL STORM MARIA IS CENTERED NEAR 17.3N 61.5W AT 10/1500 UTC
OR 20 NM NE OF ANTIGUA AND 270 NM E-SE OF SAN JUAN PUERTO RICO
MOVING NW AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007
MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT.
NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS FROM 09N TO
22N BETWEEN 57W AND 62W. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

POST-TROPICAL CYCLONE KATIA IS CENTERED NEAR 44.7N 47.7W AT
10/1500 UTC OR 255 NM E-SE OF CAPE RACE NEWFOUNDLAND AND 1700 NM
W-SW OF GLASGOW SCOTLAND MOVING E-NE AT 46 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 954 MB. MAXIMUM SUSTAINED WIND SPEED IS 70
KT WITH GUSTS TO 85 KT. WIDELY SCATTERED MODERATE CONVECTION IS
WITHIN 240 NM NORTH QUADRANT OF THE CENTER OF KATIA. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 17N38W TO 08N45W MOVING W AT
15-20 KT. A FAIRLY AMPLIFIED AND ELONGATED LOW-LEVEL CYCLONIC
FLOW IS EVIDENT ON VISIBLE SATELLITE IMAGERY IN THE VICINITY OF
THE WAVE AXIS ACROSS THE CENTRAL TROPICAL ATLC. TOTAL
PRECIPITABLE WATER IMAGERY ALSO INDICATES THE PRESENCE OF
INCREASED LOW-LEVEL MOISTURE FROM 10N TO 19N BETWEEN 35W AND
44W. SCATTERED MODERATE CONVECTION REMAINS MOSTLY EAST OF THE
WAVE AXIS OCCURRING FROM 10N TO 14N BETWEEN 36W AND 43W.
ISOLATED MODERATE CONVECTION IS ALSO OCCURRING WITHIN 30 NM
EITHER SIDE OF A LINE FROM 13N44W TO 10N48W.

TROPICAL WAVE IS ANALYZED FROM 18N79W TO 10N80W MOVING W AT
10-15 KT. THE WAVE IS BECOMING EMBEDDED WITHIN A BROAD LOW-LEVEL
CYCLONIC MONSOONAL GYRE ACROSS THE SW CARIBBEAN UNDER FAIRLY
DIVERGENT UPPER LEVEL FLOW DUE TO UPPER LEVEL RIDGING ACROSS THE
CENTRAL CARIBBEAN SEA. WIDELY SCATTERED MODERATE CONVECTION IS
PRIMARILY OCCURRING EAST OF THE WAVE AXIS FROM 13N TO 17N
BETWEEN 74W AND 79W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO
07N20W TO 07N27W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 07N27W TO 13N40W THEN RESUMES NEAR 08N46W TO
09N56W. SCATTERED MODERATE CONVECTION IS FROM 07N TO 11N BETWEEN
14W AND 18W...AND FROM 05N TO 10N BETWEEN 27W AND 32W.

...DISCUSSION...

GULF OF MEXICO...
WHILE TROPICAL STORM NATE CONTINUES TO TRACK ACROSS THE
SOUTHWESTERN GULF THIS AFTERNOON...A DISSIPATING STATIONARY
FRONTAL BOUNDARY EXTENDS FROM THE SW NORTH ATLC WATERS ACROSS
THE CENTRAL FLORIDA PENINSULA INTO THE EASTERN GULF WATERS ALONG
28N83W TO 26N88W. ISOLATED SHOWERS AND TSTMS ARE EVIDENT ON
TAMPA BAY DOPPLER RADAR IMAGERY OCCURRING WITHIN 15 NM OF A LINE
FROM 28N82W TO 27N83W. OTHERWISE...CONVECTION IS LIMITED TO THE
WESTERN GULF W OF 90W IN ASSOCIATION WITH NATE. ACROSS EXTREME
PORTIONS OF THE NW GULF...INFLUENCES FROM A 1017 MB HIGH
CENTERED OVER SE LOUISIANA ARE PROVIDING FOR MOSTLY CLEAR SKIES
AND FAIR CONDITIONS N OF 27N. UPPER LEVEL RIDGING EXTENDS ACROSS
THE SOUTHERN GULF WITH RIDGE AXIS FROM 28N75W IN THE SW NORTH
ATLC TO 21N94W WHICH IS PROVIDING NATE WITH AMPLE UPPER LEVEL
DIFFLUENCE TO SUSTAIN CONVECTION OVER THE SW GULF.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE IS MOSTLY IN CONTROL OVER MUCH OF THE
CENTRAL AND WESTERN CARIBBEAN PROVIDING OVERALL EASTERLY
DIFFLUENT UPPER LEVEL FLOW. WITH LOW-LEVEL MOISTURE IN PLACE
BETWEEN A LOW-LEVEL MONSOONAL GYRE CENTERED OVER THE SW
CARIBBEAN AND A TROPICAL WAVE MOVING W NEAR 80W...WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER MUCH OF
THE CARIBBEAN BASIN THIS AFTERNOON S OF 20N W OF 72W. THE ONLY
SIGNIFICANT CONCENTRATION OF CONVECTIVE ACTIVITY IS THE CLUSTER
OF SHOWERS AND TSTMS LOCATED EAST OF THE TROPICAL WAVE FROM
13N-17N BETWEEN 74W-79W. OVER THE EASTERN CARIBBEAN...TROPICAL
STORM MARIA CONTINUES TO IMPACT THE LEEWARD ISLANDS AND NE
CARIBBEAN WITH CONVECTION STRETCHING FROM NEAR TRINIDAD AND
TOBAGO NORTHWARD TO 22N BETWEEN 57W-62W. AS THE STORM TRACKS NW
OVER THE NEXT 24 HOURS...HEAVY PRECIPITATION IS EXPECTED TO
CONTINUE OVER THE LESSER ANTILLES...US/UK VIRGIN ISLANDS...AND
PUERTO RICO.

ATLANTIC OCEAN...
TROPICAL STORM MARIA CONTINUES TO SKIRT THE LEEWARD ISLANDS
WHILE THE CENTER REMAINS IN THE TROPICAL NORTH ATLC WATERS.
SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS A LARGE PORTION
OF THE WATERS EAST OF THE LESSER ANTILLES FROM 09N-22N BETWEEN
57W-62W. SOME OF THIS PRECIPITATION AND DEBRIS MOISTURE IS BEING
ADVECTED TO THE NORTH DUE TO AN UPPER LEVEL LOW CENTERED NEAR
25N63W. OTHERWISE OVER THE SW NORTH ATLC...AN UPPER LEVEL RIDGE
IS CENTERED NEAR 29N74W AND IS PROVIDING A DIFFLUENT ENVIRONMENT
BETWEEN THE RIDGE AND UPPER LEVEL TROUGHING OVER THE EASTERN
CONUS. AT THE SURFACE...A DISSIPATING STATIONARY FRONT IS
ANALYZED FROM 30N78W TO THE CAPE CANAVERAL AREA WITH ISOLATED
SHOWERS AND TSTMS FROM 29N-31N BETWEEN 69W-79W. ALSO A SURFACE
TROUGH IS ANALYZED FROM 26N72W TO 22N75W AND IS PROVIDING
ISOLATED SHOWERS TO THE SE BAHAMAS AND ADJACENT ATLC WATERS FROM
22N-27N BETWEEN 70W-75W. THE REMAINDER OF THE CENTRAL AND
EASTERN ATLC WATERS ARE UNDER THE INFLUENCE OF SURFACE RIDGING
ANCHORED BY A 1022 MB HIGH CENTERED NEAR 29N31W AND A 1020 MB
HIGH CENTERED NEAR 29N55W.

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

$$
HUFFMAN



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