[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 141758
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE SEP 14 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 18.3N 52.3W AT 14/1500 UTC OR
ABOUT 615 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING WNW AT 6
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 945 MB. MAXIMUM
SUSTAINED WIND SPEED IS 115 KT WITH GUSTS TO 140 KT. VISIBLE
SATELLITE PRESENTATION SHOWS IGOR HAS MAINTAINED A WELL-DEFINED
EYE AND VERY GOOD CIRRUS OUTFLOW IN ALL DIRECTIONS. NUMEROUS
STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER WHILE NUMEROUS
MODERATE AND SCATTERED STRONG CONVECTION IS ELSEWHERE FROM
15N-21N BETWEEN 48W-55W. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

HURRICANE JULIA IS CENTERED NEAR 16.2N 29.5W AT 14/1500 UTC OR
ABOUT 305 NM WNW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING
WNW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 984 MB.
MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT.
ADDITIONAL STRENGTHENING IS POSSIBLE OVER THE NEXT 12-24 HOURS
BEFORE JULIA COMES UNDER INCREASED WESTERLY SHEAR THAT WILL
IMPACT THE CYCLONE. NUMEROUS MODERATE AND SCATTERED STRONG
CONVECTION IS WITHIN 120 NM OF THE CENTER WHILE SCATTERED
MODERATE AND ISOLATED STRONG IS ELSEWHERE FROM 13N-20N BETWEEN
26W-33W. 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 1006 MB LOW CENTERED NEAR 18N82W. A SURFACE
TROUGH EXTENDS FROM THE LOW CENTERED SOUTHWARD TO NEAR 11N83W
MOVING WNW NEAR 10-15 KT. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION LOCATED FROM 18N-21N BETWEEN 76W-82W AND WITHIN 240
NM OF THE NW QUADRANT. THIS CONVECTIVE ACTIVITY IS ALSO LIKELY
ENHANCED BY AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED
OVER CENTRAL CUBA NEAR 22N80W. SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION IS ALSO NORTH OF CUBA FROM 20N-24N BETWEEN
72W-81W AND OVER THE SW CARIBBEAN SEA FROM 09N-12N BETWEEN
77W-85W. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE FOR
DEVELOPMENT OF A TROPICAL CYCLONE OVER THE NEXT 48 HOURS.

...ITCZ...

A MONSOONAL TROUGH REMAINS ACROSS THE ATLC BASIN BETWEEN
HURRICANES IGOR AND JULIA ANALYZED AS A SURFACE TROUGH ALONG
12N33W TO 12N39W TO 14N42W. S-SW LOW-LEVEL FLOW EXTENDS EAST OF
33W TO THE AFRICAN COAST NEAR 08N13W. SCATTERED MODERATE
CONVECTION IS FROM 02N-09N BETWEEN 06W-28W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE NW
GULF NEAR 29N92W AND IS PROVIDING THE FLORIDA PENINSULA AND MUCH
OF THE GULF N OF 22N WITH NORTHWESTERLY UPPER LEVEL FLOW OVER
THE NE GULF AND FLORIDA PENINSULA AND EASTERLY UPPER LEVEL FLOW
S OF 29N W OF 85W. WATER VAPOR IMAGERY ALSO INDICATES THIS IS
USHERING IN MODERATELY DRY AIR OVER THE NORTH CENTRAL GULF AND
EASTERN GULF E OF 90W. HOWEVER...WHILE DRY AIR EXISTS IN THE
MIDDLE TO UPPER LEVELS...A LINGERING STATIONARY FRONTAL BOUNDARY
IS ANALYZED IN THE W ATLC TO THE FLORIDA COAST NEAR KEY
BISCAYNE. AS THIS BOUNDARY BECOMES MORE DIFFUSE TO THE WEST OVER
THE EASTERN GULF...ISOLATED SHOWERS ARE S OF 26N E OF 85W.
ELSEWHERE N OF 22N...PRIMARILY E WINDS ARE OBSERVED UP TO 15 KT.
FINALLY...A SURFACE TROUGH IS ANALYZED FROM 18N93W TO 22N95W AND
IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS OVER
THE BAY OF CAMPECHE S OF 22N W OF 93W.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER CENTRAL CUBA NEAR
22N80W AND CONTINUES TO PROVIDE MUCH OF THE BASIN WITH UPPER
LEVEL EASTERLY FLOW W OF 68W. A WEAKNESS ON THE WESTERN
PERIPHERY OF THE RIDGE IS ASSOCIATED WITH THE 1006 MB SPECIAL
FEATURES LOW CENTER AND SURFACE TROUGHING ACROSS THE WESTERN
CARIBBEAN. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
LOCATED FROM 18N-21N BETWEEN 76W-82W AND WITHIN 240 NM OF THE NW
QUADRANT OF THE LOW CENTER. ALSO FARTHER SOUTH OVER THE SW
CARIBBEAN...SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
FROM 09N-12N BETWEEN 77W-85W. WATER VAPOR IMAGERY INDICATES THAT
MOSTLY DRY AIR AND STRONG SUBSIDENCE IS OVER THE EASTERN
CARIBBEAN AND LEEWARD ISLANDS PROVIDING OVERALL FAIR CONDITIONS
AND CLEAR SKIES THIS AFTERNOON.

ATLANTIC OCEAN...
DRY NORTHWESTERLY UPPER LEVEL FLOW RESIDES W OF 63W OVER THE SW
NORTH ATLC DUE TO AN UPPER LEVEL ANTICYCLONE CENTERED IN THE NW
GULF OF MEXICO NEAR 29N92W. THIS UPPER LEVEL ENVIRONMENT IS
SUPPORTING A 1022 MB HIGH CENTERED OVER EASTERN NORTH CAROLINA
NEAR 35N83W. FARTHER EAST...AN UPPER LEVEL TROUGH AXIS EXTENDS
FROM 32N61W TO 24N70W AND SUPPORTS A 1010 MB LOW CENTERED NEAR
37N66W AND A COLD FRONT THAT EXTENDS FROM THE LOW TO 31N68W THEN
CONTINUES AS A STATIONARY FRONT ALONG 27N73W TO THE FLORIDA
COAST NEAR BISCAYNE BAY. WHILE THE FRONT LACKS ANY SIGNIFICANT
DEEP CONVECTION...ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE
OF THE BOUNDARY. FARTHER SOUTH...WHILE THE UPPER LEVEL TROUGH
AXIS WEAKENS NE OF CUBA...UPPER LEVEL DIFFLUENCE IS OVER FAR SW
PORTION OF THE SW NORTH ATLC. THIS ALONG WITH THE BROAD AREA OF
LOWER PRESSURE OVER THE NW CARIBBEAN SEA...EXTENDING FROM THE
SPECIAL FEATURES LOW...IS GENERATING SCATTERED SHOWERS AND TSTMS
FROM 20N-23N BETWEEN 69W-78W...INCLUDING THE SE BAHAMAS...TURKS
AND CAICOS ISLANDS...AND THE NORTHERN COAST OF CUBA. OVER THE
CENTRAL ATLC...ANOTHER REMNANT FRONTAL BOUNDARY ANALYZED AS A
SURFACE TROUGH IS POSITIONED FROM 31N56W TO 27N61W. ISOLATED
SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS. THE
REMAINDER OF THE EASTERN ATLC IS DOMINATED BY SURFACE RIDGING
ANCHORED BY A 1030 MB HIGH CENTERED N OF THE AZORES NEAR 44N28W.
AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER W AFRICA NEAR 23N13W
WITH AN UPPER LEVEL RIDGE AXIS EXTENDING SW TO THE CAPE VERDE
ISLANDS NEAR 15N26W.

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

$$
HUFFMAN




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