[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON SEP 13 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 17.5N 49.7W AT 13/1500 UTC OR
ABOUT 765 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING W AT 9 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 933 MB. MAXIMUM SUSTAINED
WIND SPEED IS 130 KT WITH GUSTS TO 160 KT. VISIBLE SATELLITE
PRESENTATION SHOWS IGOR HAS A WELL-DEFINED EYE AND FAIRLY
SYMMETRICAL CONVECTION. NUMEROUS STRONG CONVECTION IS WITHIN 90
NM OF THE CENTER WHILE NUMEROUS MODERATE AND SCATTERED STRONG
CONVECTION IS ELSEWHERE FROM 15N-21N BETWEEN 45W-53W. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS.

TROPICAL STORM JULIA IS CENTERED NEAR 15.1N 26.7W AT 13/1800 UTC
OR ABOUT 135 NM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING
WNW AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB.
MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT.
GRADUAL STRENGTHENING IS FORECAST OVER THE NEXT COUPLE OF DAYS
DUE TO A FAVORABLE UPPER LEVEL DIFFLUENT ENVIRONMENT. NUMEROUS
MODERATE AND SCATTERED STRONG CONVECTION IS FROM 13N-17N BETWEEN
25W-29W. 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.

A BROAD LOW PRESSURE AREA IS LOCATED IN THE WESTERN CARIBBEAN
SEA FOCUSED ON A 1008 MB LOW CENTERED NEAR 16N77W. A SURFACE
TROUGH EXTENDS FROM NEAR 19N75W THROUGH THE LOW CENTER TO 10N81W
MOVING WNW NEAR 10 KT. SCATTERED MODERATE TO STRONG CONVECTION
IS OCCURRING FROM 14N-20N BETWEEN 75W-81W AND IS LIKELY ENHANCED
BY AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER
HISPANIOLA NEAR 19N73W. ISOLATED MODERATE CONVECTION IS ALSO
FROM 13N-18N BETWEEN 72W-75W AND FROM 09N-13N BETWEEN 76W-82W.
WHILE CONVECTION ALONG THE SURFACE TROUGH AND NEAR THE LOW
CENTERED REMAIN LARGELY UNORGANIZED...ENVIRONMENTAL CONDITIONS
REMAIN FAVORABLE FOR DEVELOPMENT OF A TROPICAL CYCLONE OVER THE
NEXT 48 HOURS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 08N27W 09N33W 15N42W RESUMING NEAR
11N54W 10N60W 11N68W. WIDELY SCATTERED MODERATE CONVECTION IS
FROM 03N-08N BETWEEN 08W-21W...AND FROM 05N-10N BETWEEN 23W-31W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE NW
GULF NEAR 29N94W AND IS PROVIDING THE FLORIDA PENINSULA AND MUCH
OF THE GULF N OF 22N WITH NE TO E UPPER LEVEL FLOW. WATER VAPOR
IMAGERY ALSO INDICATES THIS IS USHERING IN A MODERATELY DRY
AIRMASS OVER THE EASTERN GULF E OF 90W. HOWEVER...AS AN UPPER
LEVEL SHORTWAVE TROUGH MOVES EASTWARD FROM THE W ATLC WATERS...A
LINGERING FRONTAL BOUNDARY IS ANALYZED ACROSS THE CENTRAL
FLORIDA PENINSULA FROM CAPE CANAVERAL TO NEW PORT RICHEY AND
INTO A 1013 MB LOW CENTERED NEAR 28N83W. A STATIONARY FRONT THEN
EXTENDS WESTWARD FROM THE LOW ALONG 28N TO THE TEXAS COAST NEAR
GALVESTON. DUE TO THE STRONGER SUBSIDENCE ALOFT OVER THE EASTERN
GULF...ONLY A ISOLATED SHOWERS ARE WITHIN 60 NM S OF THE FRONT
BETWEEN 91W-96W. ELSEWHERE N OF 22N PRIMARILY NE TO E WINDS UP
TO 15 KT. FINALLY...A SURFACE TROUGH IS FROM 19N-22N ALONG 93W
AND IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS
OVER THE BAY OF CAMPECHE S OF 21N.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER HISPANIOLA NEAR
19N73W AND CONTINUES TO PROVIDE MUCH OF THE BASIN WITH UPPER
LEVEL EASTERLY FLOW. A WEAKNESS ON THE SW PERIPHERY OF THE RIDGE
IS ASSOCIATED WITH THE 1008 MB SPECIAL FEATURES LOW CENTER AND
SURFACE TROUGHING ACROSS THE WESTERN CARIBBEAN. NUMEROUS SHOWERS
AND SCATTERED TSTMS ARE N OF 14N...OVER JAMAICA...TO THE SE
COAST OF CUBA NEAR 20N BETWEEN 75W-81W. ELSEWHERE BETWEEN 71W
AND 83W...ISOLATED SHOWERS AND TSTMS ARE OCCURRING DUE TO THE
LARGE-SCALE LOW-LEVEL TROUGHING THAT EXISTS OVER THE CENTRAL AND
WESTERN CARIBBEAN. WATER VAPOR IMAGERY INDICATES THAT MOSTLY DRY
AIR AND STRONG SUBSIDENCE IS OVER THE NE CARIBBEAN AND LEEWARD
ISLANDS PROVIDING OVERALL FAIR CONDITIONS AND CLEAR SKIES THIS
AFTERNOON.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS OVER THE WESTERN ATLC FROM
NORTH OF THE DISCUSSION AREA NEAR 35N70W TO THE CENTRAL BAHAMAS
NEAR 25N75W. THIS UPPER LEVEL TROUGHING SUPPORTS A 1009 MB LOW
CENTERED NEAR 35N72W AND A COLD FRONT THAT EXTENDS FROM THE LOW
TO 31N77W. WHILE THE FRONT LACKS ANY SIGNIFICANT DEEP
CONVECTION...POSSIBLE ISOLATED SHOWERS ARE FROM 30N-32N W OF
77W. A SURFACE TROUGH EXTENDS FROM 31N74W EAST OF THE COLD FRONT
TO THE FLORIDA PENINSULA NEAR CAPE CANAVERAL. COASTAL DOPPLER
RADAR INDICATES ISOLATED SHOWERS WITHIN 90 NM S OF THE SURFACE
TROUGH OVER THE W ATLC WATERS W OF 77W. FARTHER SOUTH...WHILE
THE UPPER LEVEL TROUGH AXIS WEAKENS ACROSS CENTRAL CUBA...MOIST
SW FLOW IS OVER FAR SOUTHERN PORTIONS OF THE SW NORTH ATLC. THIS
ALONG WITH LOW-LEVEL TROUGHING EXTENDING FROM THE SPECIAL
FEATURES LOW IN THE WESTERN CARIBBEAN SEA...IS GENERATING
SCATTERED SHOWERS AND ISOLATED TSTMS FROM 20N-23N BETWEEN
69W-78W...INCLUDING THE SE BAHAMAS...TURKS AND CAICOS ISLANDS...
AND EASTERN CUBA. OVER THE CENTRAL ATLC...ANOTHER UPPER LEVEL
LOW IS CENTERED NORTH OF THE AREA NEAR 39N49W AND SUPPORTS A
COLD FRONT EXTENDING FROM 32N53W TO 28N60W TO 27N71W. ISOLATED
SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE FRONT BETWEEN
51W-71W...AND SCATTERED SHOWERS AND ISOLATED TSTMS ARE N OF 29N
BETWEEN 45W-51W. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED
BY SURFACE RIDGING ANCHORED BY A 1032 MB HIGH CENTERED N OF THE
AZORES NEAR 44N24W. AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER
W AFRICA NEAR 20N06W WITH AN UPPER LEVEL RIDGE AXIS EXTENDING
ALONG 19N TO NORTH OF T.S. JULIA NEAR 19N27W. SCATTERED SHOWERS
AND TSTMS ARE ENHANCED DUE TO UPPER LEVEL DIFFLUENCE NE OF THE
CAPE VERDE ISLANDS FROM 17N-21N BETWEEN 19W-24W.

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

$$
HUFFMAN




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