[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200613
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON SEP 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...SPECIAL FEATURES...

HURRICANE IGOR IS CENTERED NEAR 33.4N 65.1W AT 20/0600 UTC OR
ABOUT 70 NM NNW OF BERMUDA MOVING NNE AT 14 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 955 MB. MAXIMUM SUSTAINED WIND SPEED
IS 65 KT WITH GUSTS TO 80 KT. THE CENTER OF IGOR HAS NOW PASSED
W OF BERMUDA AND TROPICAL STORM FORCE WINDS CONTINUE TO BE
REPORTED AS IGOR MOVES FARTHER AWAY. 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. MOST OF THE SHOWER ACTIVITY IS N OF THE
CENTER. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM
31N-41N BETWEEN 60W-72W.

TROPICAL STORM JULIA IS CENTERED NEAR 32.2N 48.7W AT 20/0300 UTC
OR ABOUT 1055 NM W OF THE AZORES MOVING NE AT 11 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WIND
SPEED IS 35 KT WITH GUSTS TO 45 KT. WEAKENING HAS OCCURRED AS
JULIA MOVES OVER COOLER WATERS AND CONTINUES TO EXPERIENCE WIND
SHEAR FROM THE OUTFLOW OF HURRICANE IGOR. THIS TREND IS EXPECTED
TO CONTINUE UNTIL JULIA DISSIPATES WITHIN 48 HRS. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION
IS FROM 32N-38N BETWEEN 40W-50W.

AN AREA OF LOW PRESSURE IS LOCATED W OF THE CAPE VERDE ISLANDS
CONCENTRATED NEAR A 1008 MB LOW NEAR 16N32W MOVING NW NEAR 5-10
KT. AN ASCAT SCATTEROMETER PASS FROM AROUND 19/2300 UTC
INDICATES CYCLONIC FLOW ABOUT THE CENTER WITH 20 KT WINDS TO THE
N. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-19N
BETWEEN 28W-35W. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR
FURTHER DEVELOPMENT INTO A TROPICAL CYCLONE DURING THE NEXT 48
HRS.

...ITCZ...

A MONSOONAL TROUGH IS ANALYZED OFF THE W AFRICAN COAST ALONG
11N15W TO 9N24W RESUMING NEAR 18N25W TO THE LOW PRESSURE SYSTEM
NEAR 16N32W TO 11N44W INDICATING AN AREA WHERE THE WINDS S OF
THE AXIS ARE MAINLY SWLY AS OPPOSED TO TYPICAL ITCZ CONVERGENCE
OF SE-NE WINDS. SCATTERED MODERATE/STRONG CONVECTION IS OFF THE
AFRICAN COAST FROM 10N-15N BETWEEN 15W-19W...AND FROM 5N-8N
BETWEEN 21W-27W. SIMILAR ACTIVITY IS ALSO FROM 7N-12N BETWEEN
33W-44W. A TRADITIONAL SURFACE TROUGH EXTENDS TO THE W ALONG
14N51W TO 5N54W ENHANCING SCATTERED MODERATE/STRONG CONVECTION
FROM 9N-14N BETWEEN 53W-57W.

...DISCUSSION...

GULF OF MEXICO...
ENHANCED MOISTURE REMAINS ACROSS THE FAR WRN GULF WHERE A
SURFACE TROUGH IS ANALYZED ALONG THE TEXAS/MEXICO COASTLINE FROM
29N93W 25N96W TO 20N95W. SURFACE CONVERGENCE NEAR THE TROUGH
ALONG WITH UPPER DIFFLUENCE ON THE BACK SIDE OF A WEAK UPPER
LEVEL WIND JET OVER LOUISIANA ARE SUPPORTING SCATTERED
SHOWERS/POSSIBLE THUNDERSTORMS FROM 24N-29N W OF 91W. THIS
ACTIVITY IS EXPECTED TO REMAIN OVER THE FAR WRN GULF FOR THE
NEXT COUPLE OF DAYS. MOSTLY FAIR WEATHER PREVAILS E OF 91W DUE
TO SUBSIDENCE ALOFT AROUND THE PERIPHERY OF AN UPPER LEVEL RIDGE
COVERING MUCH OF THE BASIN CENTERED OVER WRN MEXICO NEAR 23N97W.
WATER VAPOR IMAGERY ALSO INDICATES DRY AIR BEING DRAWN AROUND
THE ERN EDGE OF THE UPPER RIDGE ACROSS FLORIDA AND THE W ATLC. A
FEW ISOLATED SHOWERS ARE NOTED OFF THE W COAST OF FLORIDA FROM
24N-27N BETWEEN 82W-84W. EXPECT FAIR WEATHER TO CONTINUE ACROSS
THE ERN HALF OF THE BASIN.

CARIBBEAN SEA...
MOSTLY FAIR WEATHER COVERS MUCH OF THE CARIBBEAN UNDER THE
INFLUENCE OF A DRY AND STABLE AIRMASS OVER THE WRN HALF OF THE
BASIN. UPPER RIDGING COVERS THE FAR NW CARIBBEAN EXTENDING FROM
THE GULF OF MEXICO WHILE UPPER LEVEL TROUGHING DIGS DOWN ACROSS
THE CENTRAL CARIBBEAN FROM THE W ATLC. ISOLATED
SHOWERS/THUNDERSTORMS ARE ACROSS THE SW CARIBBEAN S OF 14N
BETWEEN 73W-84W ASSOCIATED WITH AN EXTENSION OF THE E PACIFIC
MONSOONAL TROUGH ACROSS COSTA RICA TO N OF COLOMBIA NEAR 13N73W.
STRONGER SHOWERS/THUNDERSTORMS ARE N OF VENEZUELA S OF 15N
BETWEEN 67W-72W IN ASSOCIATION WITH AN AREA OF ENHANCED MOISTURE
THAT HAS BEEN MOVING ACROSS THE ERN CARIBBEAN IN THE WAKE OF
HURRICANE IGOR NOW WELL TO THE N. THIS AREA OF MOISTURE IS ALSO
ENHANCING SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE LESSER
ANTILLES E OF 65W. LARGE SWELLS CONTINUE TO IMPACT
HISPANIOLA...PUERTO RICO...THE VIRGIN ISLANDS...AND THE LEEWARD
ISLANDS IN ASSOCIATION WITH IGOR...AND ARE BEGINNING TO
GRADUALLY SUBSIDE. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE OVER
THE ERN CARIBBEAN OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
THE FAR W ATLC IS EXPERIENCING MOSTLY FAIR WEATHER ASSOCIATED
WITH DRY AIR SINKING DOWN INTO THE AREA AROUND AN UPPER LEVEL
RIDGE COVERING THE GULF OF MEXICO AND AN UPPER LEVEL TROUGH
ACROSS THE W ATLC. TO THE NE...HURRICANE IGOR IS MOVING PAST
BERMUDA WITH TROPICAL STORM JULIA TO THE NE OF IGOR. SEE SPECIAL
FEATURES FOR MORE DETAILS ON BOTH OF THESE SYSTEMS. ENHANCED
MOISTURE ACROSS THE LESSER ANTILLES CONTINUES TO BE DRAWN NWD IN
THE WAKE OF IGOR SUPPORTING AREAS OF SHOWERS/THUNDERSTORMS S OF
23N BETWEEN 60W-65W. E OF JULIA...SURFACE RIDGING PREVAILS
AROUND A 1022 MB HIGH W OF THE AZORES ISLANDS PROVIDING
GENERALLY FAIR WEATHER ACROSS THE E ATLC N OF THE LOW PRESSURE
SYSTEM W OF THE CAPE VERDE ISLANDS. ALOFT...AN UPPER LEVEL RIDGE
COVERS THE CENTRAL ATLC CENTERED NEAR 30N52W WITH AN UPPER LEVEL
TROUGH TO THE E EXTENDING FROM PORTUGAL TO THE CANARY ISLANDS.

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

$$
WALTON






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