[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190559
TWDAT

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

...SPECIAL FEATURES...

HURRICANE IGOR IS CENTERED NEAR 28.3N 65.1W AT 19/0600 UTC OR
ABOUT 240 NM S OF BERMUDA MOVING NNW AT 9 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 949 MB. MAXIMUM SUSTAINED WIND SPEED IS 80
KT WITH GUSTS TO 100 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 27N-29N BETWEEN 64W-65W. NUMEROUS
MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 26N-32N
BETWEEN 62W-68W.

TROPICAL STORM JULIA IS CENTERED NEAR 32.4N 51.9W AT 19/0300 UTC
OR ABOUT 1265 NM W OF THE AZORES MOVING N AT 12 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 998 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
30N-33N BETWEEN 49W-53W WITH NUMEROUS MODERATE/ISOLATED STRONG
CONVECTION ELSEWHERE FROM 29N-34N BETWEEN 48W-53W.

A BROAD AREA OF LOW PRESSURE IS LOCATED W OF THE CAPE VERDE
ISLANDS CONCENTRATED NEAR A 1009 MB LOW NEAR 13N29W 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-17N BETWEEN 27W-34W...AND ACROSS THE CAPE
VERDE ISLANDS FROM 17N-18N BETWEEN 23W-25W. 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
9N12W TO 7N26W PICKING UP TO THE N ALONG 13N25W TO 11N40W
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
11N42W TO 10N56W. SCATTERED MODERATE/STRONG CONVECTION IS OFF
THE AFRICAN COAST FROM 7N-17N BETWEEN 13W-19W. ISOLATED
MODERATE/STRONG CONVECTION IS FROM 6N-8N BETWEEN 22W-29W...AND
FROM 6N-16N BETWEEN 44W-50W9N-18N BETWEEN 52W-61W 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. A SURFACE TROUGH PARALLELS THE
SRN TEXAS/ERN MEXICO COASTLINE ALONG 28N95W 23N96W 18N93W.
SURFACE CONVERGENCE NEAR THE TROUGH ALONG WITH THE MOISTURE OVER
THE AREA ARE SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM
23N-29N W OF 91W WITH ISOLATED SHOWERS/THUNDERSTORMS S OF 23N 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 91W
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 TONIGHT 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 S OF CUBA FROM 19N-21N BETWEEN
75W-84W. SHOWERS/THUNDERSTORMS ARE ALSO OFF THE NRN COAST OF
VENEZUELA FROM 11N-13N BETWEEN 68W-74W MOST LIKELY ASSOCIATED
WITH AN EXTENSION OF THE E PACIFIC MONSOONAL TROUGH EXTENDING
FROM PANAMA TO THE NRN TIP OF COLOMBIA NEAR 13N73W. 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 9N-20N
BETWEEN 56W-65W. E OF JULIA...SURFACE RIDGING PREVAILS AROUND A
1026 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 NEAR 30N49W WITH AN UPPER LEVEL TROUGH TO THE E
EXTENDING FROM PORTUGAL ACROSS THE CANARY ISLANDS TO NEAR
22N32W.

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

$$
WALTON





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