[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191220 AAA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN SEP 19 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

HURRICANE IGOR IS CENTERED NEAR 29.6N 65.3W AT 19/1200 UTC OR
ABOUT 190 NM S OF BERMUDA MOVING NNW AT 11 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 949 MB. MAXIMUM SUSTAINED WIND SPEED IS 75
KT WITH GUSTS TO 90 KT. IGOR REMAINS LARGE AND TROPICAL STORM
CONDITIONS ARE BEGINNING TO IMPACT BERMUDA. 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 28N-30N BETWEEN 63W-66W. NUMEROUS
MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 27N-36N
BETWEEN 62W-69W.

TROPICAL STORM JULIA IS CENTERED NEAR 33.8N 51.8W AT 19/0900 UTC
OR ABOUT 1235 NM W OF THE AZORES MOVING N AT 14 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 995 MB. MAXIMUM SUSTAINED WIND SPEED
IS 45 KT WITH GUSTS TO 55 KT. WEAKENING IS EXPECTED AS JULIA
MOVES NWD AND CONTINUES TO EXPERIENCE WIND SHEAR FROM THE
OUTFLOW OF HURRICANE IGOR 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
32N-34N BETWEEN 50W-52W WITH NUMEROUS MODERATE/ISOLATED STRONG
CONVECTION ELSEWHERE FROM 30N-36N BETWEEN 46W-53W.

AN AREA OF LOW PRESSURE IS LOCATED W OF THE CAPE VERDE
ISLANDS CONCENTRATED NEAR A 1008 MB LOW NEAR 14N30W MOVING W
NEAR 5-10 KT. CONVECTION ASSOCIATED WITH THIS SYSTEM HAS
INCREASED WITH SCATTERED MODERATE/STRONG CONVECTION MAINLY N OF
THE CENTER FROM 14N-18N BETWEEN 27W-33W. ENVIRONMENTAL
CONDITIONS ARE BECOMING MORE FAVORABLE FOR FURTHER DEVELOPMENT
OF THIS SYSTEM OVER THE NEXT COUPLE OF DAYS.

...ITCZ...

A MONSOONAL TROUGH IS ANALYZED OFF THE W AFRICAN COAST ALONG
11N12W TO 14N24W RESUMING NEAR 14N31W TO 11N41W INDICATING AN
AREA WHERE THE WINDS S OF THE AXIS ARE MAINLY SWLY AS OPPOSED TO
TYPICAL ITCZ CONVERGENCE OF SE-NE WINDS. THE TRADITIONAL ITCZ
AXIS CONTINUES W OF THE MONSOON TROUGH ALONG 10N43W TO 8N56W.
SCATTERED MODERATE/STRONG CONVECTION IS OFF THE AFRICAN COAST
FROM 7N-15N BETWEEN 13W-20W. SIMILAR ACTIVITY IS FROM 12N-15N
BETWEEN 34W-40W...AND FROM 10N-14N BETWEEN 46W-51W. ISOLATED
MODERATE/STRONG CONVECTION IS FROM 6N-13N BETWEEN 55W-60W
EMBEDDED IN MOISTURE LEFT IN IGORS WAKE.

...DISCUSSION...

GULF OF MEXICO...
SIGNIFICANT MOISTURE LIES ACROSS THE FAR WRN GULF IN THE WAKE OF
KARL WHICH DISSIPATED YESTERDAY. AS OF 0900 UTC...A SURFACE
TROUGH PARALLELS THE TEXAS COASTLINE ALONG 30N92W 29N96W 25N99W.
SURFACE CONVERGENCE NEAR THE TROUGH ALONG WITH THE MOISTURE OVER
THE AREA ARE SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM
23N-29N W OF 93W WITH ISOLATED SHOWERS/THUNDERSTORMS S OF 20N W
OF 91W. THIS ACTIVITY IS EXPECTED TO REMAIN OVER THE FAR WRN
GULF FOR THE NEXT COUPLE OF DAYS. FAIR WEATHER PREVAILS E OF 92W
DUE TO SUBSIDENCE ALOFT AROUND THE PERIPHERY OF AN UPPER LEVEL
RIDGE COVERING MUCH OF THE BASIN. WATER VAPOR IMAGERY ALSO
INDICATES DRY AIR BEING DRAWN AROUND THE ERN EDGE OF THE UPPER
RIDGE ACROSS FLORIDA AND THE W ATLC. 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 AROUND AN UPPER LEVEL INVERTED TROUGH CENTERED SW OF
NICARAGUA. WEAK UPPER LEVEL RIDGING COVERS THE ERN HALF OF THE
AREA CENTERED N OF VENEZUELA. A FEW ISOLATED
SHOWERS/THUNDERSTORMS ARE IN THE NW CARIBBEAN FROM 20N-22N
BETWEEN 81W-88W...AND FROM 17N-20N BETWEEN 76W-80W.
SHOWERS/THUNDERSTORMS ARE ALSO OFF THE NRN COAST OF VENEZUELA S
OF 15N BETWEEN 66W-71W. ISOLATED SHOWERS/THUNDERSTORMS ARE
ACROSS THE SW CARIBBEAN S OF 14N BETWEEN 70W-84W ASSOCIATED WITH
AN EXTENSION OF THE E PACIFIC MONSOONAL TROUGH ACROSS NICARAGUA
TO N OF VENEZUELA. CYCLONIC SURFACE FLOW FROM THE CIRCULATION OF
HURRICANE IGOR IS INFLUENCING THE NE CARIBBEAN PRODUCING SW-W
WINDS ACROSS THE NE ISLANDS. LARGE SWELLS CONTINUE TO IMPACT
HISPANIOLA...PUERTO RICO...THE VIRGIN ISLANDS...AND THE LEEWARD
ISLANDS IN ASSOCIATION WITH IGOR...AND ARE EXPECTED TO BEGIN
GRADUALLY SUBSIDING OVER THE NEXT COUPLE OF DAYS.
SHOWERS/THUNDERSTORMS REMAIN ACROSS THE LESSER ANTILLES E OF 65W
ASSOCIATED WITH MOISTURE LEFT BEHIND BY IGOR. THIS MOISTURE IS
FORECAST TO MOVE WWD INCREASING THE CHANCES OF ENHANCED
SHOWER/THUNDERSTORM ACTIVITY ACROSS THE ERN CARIBBEAN.

ATLANTIC OCEAN...
THE FAR W ATLC IS EXPERIENCING MOSTLY FAIR WEATHER ASSOCIATED
WITH DRY AIR AND SUBSIDENCE ALOFT AROUND AN UPPER LEVEL RIDGE
COVERING THE GULF OF MEXICO. TO THE E...HURRICANE IGOR IS MOVING
TOWARDS BERMUDA WITH TROPICAL STORM JULIA TO THE NE OF IGOR. SEE
SPECIAL FEATURES FOR MORE DETAILS ON BOTH OF THESE SYSTEMS. E OF
THE LESSER ANTILLES MOISTURE IS BEING DRAWN NWD IN THE WAKE OF
IGOR SUPPORTING AREAS OF SHOWERS/THUNDERSTORMS FROM 6N-20N
BETWEEN 55W-61W. E OF JULIA...SURFACE RIDGING PREVAILS AROUND A
1024 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 HAS FORMED NEAR
JULIA CENTERED AT 29N49W WITH AN UPPER LEVEL TROUGH TO THE E
EXTENDING FROM PORTUGAL ACROSS THE CANARY ISLANDS TO NEAR
22N35W.

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

$$
WALTON







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