[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT SEP 18 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

HURRICANE IGOR IS CENTERED NEAR 26.6N 64.1W AT 18/1800 UTC OR
ABOUT 400 NM S OF BERMUDA MOVING NW AT 11 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 945 MB. MAXIMUM SUSTAINED WIND SPEED
IS 95 KT WITH GUSTS TO 115 KT. IGOR REMAINS LARGE AND OUTER
RAINBANDS ARE EXPECTED TO BEGIN IMPACTING BERMUDA DURING THE
NEXT 12-18 HRS. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY
UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 AND THE FULL
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS FROM 24N-28N
BETWEEN 62W-65W. SCATTERED MODERATE CONVECTION IS ELSEWHERE
FROM 22N-29N BETWEEN 61W-67W.

TROPICAL STORM JULIA IS CENTERED NEAR 28.9N 51.0W AT 18/1500 UTC
OR ABOUT 1515 NM WSW OF THE AZORES MOVING NW AT 16 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WIND SPEED
IS 45 KT WITH GUSTS TO 55 KT. WATER VAPOR IMAGERY AND SATELLITE
DERIVED WINDS INDICATE THAT THE UPPER LEVEL OUTFLOW OF IGOR IS
SHEARING JULIA RESULTING IN THE WEAKENING TO TROPICAL STORM
FORCE. FURTHER WEAKENING IS EXPECTED OVER THE NEXT SEVERAL DAYS.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. NUMEROUS STRONG
CONVECTION IS FROM 26N-29N BETWEEN 49W-51W WITH SCATTERED
MODERATE CONVECTION IS ELSEWHERE FROM 25N-30N BETWEEN 47W-52W.

...TROPICAL WAVES OR TROPICAL LOWS...

1008 MB LOW IS SW OF THE CAPE VERDE ISLANDS NEAR 13N27W MOVING W
NEAR 15 KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES AN AREA
OF MAXIMUM MOISTURE SURROUNDING THE LOW. WIDELY SCATTERED
MODERATE CONVECTION IS NW OF THE CENTER FROM 12N-17N BETWEEN
25W-31W.

...ITCZ...

THE ITCZ AXIS HAS MAINLY BROKEN DOWN DUE TO THE LARGE SCALE WIND
FIELD FROM IGOR AND JULIA. ONLY A PORTION REMAINS ALONG 10N38W
10N48W. WIDELY SCATTERED MODERATE CONVECTION IS OFF THE COAST
OF SOUTH AMERICA FROM 4N-9N BETWEEN 45W-51W. FURTHER W NEAR THE
WINDWARD ISLANDS...ISOLATED MODERATE CONVECTION IS FROM 7N-14N
BETWEEN 56W-60W EMBEDDED IN MOISTURE BEING DRAWN NWD BEHIND
IGOR. ELSEWHERE...SCATTERED MODERATE CONVECTION IS OFF THE COAST
OF WEST AFRICA FROM 4N-9N BETWEEN 10W-17W.

...DISCUSSION...

GULF OF MEXICO...
A 1008 MB LOW...THE REMNANTS OF HURRICANE KARL...IS INLAND OVER
S MEXICO NEAR 18N98W. MOST ALL CONVECTION HAS DISSIPATED NEAR
THE LOW CENTER. THE W GULF OF MEXICO HOWEVER STILL HAS SCATTERED
MODERATE TO NUMEROUS STRONG CONVECTION FURTHER N FROM 20N-30N
BETWEEN 92W-99W. THE REMAINDER OF THE GULF AND FLORIDA HAS
MOSTLY FAIR WEATHER. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH
IS CENTERED OVER THE CENTRAL GULF NEAR 26N90W. CONSIDERABLE
UPPER LEVEL MOISTURE COVERS THE GULF W OF 85W. EXPECT...
CONTINUED CONVECTION OVER S TEXAS AND THE W GULF OVER THE NEXT
24 HOURS.

CARIBBEAN SEA...
A BROAD AREA OF UPPER LEVEL MOISTURE COVERS THE NE CARIBBEAN E
OF 70W DUE TO HURRICANE IGOR. SCATTERED SHOWERS ARE OVER THE
LEEWARD ISLANDS AND PUERTO RICO N OF 16N AS NOTED BY RADAR.
WIDELY SCATTERED MODERATE CONVECTION IS OVER THE WINDWARD
ISLANDS FROM 11N-15N BETWEEN 60W-64W. ELSEWHERE... SCATTERED
MODERATE CONVECTION IS OVER N COLOMBIA AND THE SW CARIBBEAN FROM
10N-12N BETWEEN 70W-83W. ELSEWHERE...SCATTERED SHOWERS ARE IN
THE VICINITY OF THE CAYMAN ISLANDS FROM 18N-21N BETWEEN 80W-83W.
WEAK 10-15 KT SURFACE WINDS COVERS MOST OF THE CARIBBEAN. IN THE
UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER THE SW
CARIBBEAN NEAR 14N83W. STRONG SUBSIDENCE COVERS THE NW
CARIBBEAN. AN UPPER LEVEL HIGH IS CENTERED OVER THE WINDWARD
ISLANDS NEAR 13N62W. CONSIDERABLE UPPER LEVEL MOISTURE IS OVER
THE E CARIBBEAN E OF 70W. EXPECT...CONTINUED SHOWERS AND
CONVECTION OVER THE E CARIBBEAN E OF 70W AND OVER THE S
CARIBBEAN S OF 15N OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
HURRICANE IGOR...T.S. JULIA...TOGETHER WITH A TROPICAL LOW ARE
THE PRIMARY SURFACE FEATURES OVER THE ATLANTIC. IGOR POSES A
THREAT TO BERMUDA. SEE ABOVE. THE IGOR EYEWALL IS NOW
APPROACHING BUOY 41049 WHERE TROPICAL STORM FORCE WINDS AND 35
FT SEAS ARE BEING REPORTED. OF INTEREST... SATELLITE IMAGERY
SHOWS THE UPPER OUTFLOW OF IGOR IS SHEARING JULIA. VISIBLE
IMAGERY ALSO SHOWS A LARGE AREA OF DUST OVER THE E ATLANTIC FROM
15N-25N E OF 40W TO W AFRICA.

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

$$
MRF/SMM






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