[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 310004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE AUG 30 2011

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURE...
TROPICAL STORM KATIA IS CENTERED NEAR 12.7N 35.4W AS OF 30/2100
UTC...OR ABOUT 750 MI...1210 KM W OF THE SOUTHERNMOST CAPE VERDE
ISLANDS MOVING WNW AT 17 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO
60 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADER MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/
ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT2/WTNT22 KNHC FOR MORE
DETAILS. MOST OF THE CONVECTION IS CENTERED WITHIN THE STORM
WITH RAIN BANDS EXTENDING 226 NM FROM THE CENTER. MODERATE
CLUSTERED CONVECTION IS FROM 10N-14N BETWEEN 33W-39.

...TROPICAL WAVES...
TROPICAL WAVE IS LOCATED IN THE WESTERN CARIBBEAN FROM 22N82W TO
HONDURAS COAST NEAR 15N84W. WATER VAPOR IMAGERY SHOW HIGH
MOISTURE COVERING THE WRN HALF OF THE CARIBBEAN. THIS IS HELPING
ENHANCE SHOWERS/THUNDERSTORMS ACROSS HALF WRN CUBA...AS WELL AS
INLAND IN HONDURAS AND NICARAGUA. SHOWERS/THUNDERSTORMS
ASSOCIATED TO THIS TROPICAL WAVE OVER THE SEA ARE FROM 14N-22N
BETWEEN 79W-85W. CONTINUED SHOWER/THUNDERSTORM ACTIVITY IN THIS
AREA CONTRIBUTED TO THE FORMATION OF THIS TROPICAL WAVE...WAVE
FORMATION AND GROWTH IS POSSIBLE IN THE WRN CARIBBEAN AND
CURRENT ATMOSPHERIC CONDITIONS WERE FAVORABLE FOR THIS TO OCCUR.
MODEL GUIDANCE ALSO SUPPORTED ITS FORMATION. IN 24 HOURS THIS
WAVE WILL CONTINUE MOVING IN A WNW-NW TRACK INTO THE GULF OF
MEXICO. THIS WILL LIKELY SUPPORT CONTINUED SHOWER/THUNDERSTORM
ACTIVITY OVER THE NW CARIBBEAN OVER THE NEXT DAY OR SO.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH IS ANALYZED ACROSS MAURITANIA FROM 21N10W SW
TO THE CAPE VERDE ISLANDS NEAR 15N25W. THE CIRCULATION OF KATIA
HAS DISRUPTED THE MONSOON TROUGH TO THE W OF THE CAPE VERDE
ISLANDS. A SMALL PORTION OF THE ITCZ EXISTS TO THE W OF KATIA
ALONG 11N48W TO THE COAST OF VENEZUELA NEAR 10N61W. THE
CONVERGENCE ALONG THE ITCZ AXIS IS GENERATING SCATTERED SHOWERS
WITHIN 148 NM N OF THE AXIS. AS KATIA MOVES WNW...THE MONSOON
TROUGH WILL RE-ESTABLISH WHILE THE ITCZ WILL BEGIN TO
BREAKDOWN.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...THE STATIONARY FRONT IN THE NE GULF HAS
DISSIPATED AS THE UPPER LEVEL TROUGH MOVED EASTWARD.
AN UPPER LEVEL RIDGED IS CARRYING DRY AIR AND SUBSIDENCE TO THE
SW REGION OF THE GULF N 26N SUPPORTING FAIR WEATHER. S OF
26N...DEEP LAYERED MOISTURE PREVAILS EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY AND WATER VAPOR IMAGERY. UPPER LEVEL
DIFFLUENCE AROUND THE E SIDE OF THE UPPER TROUGH ALONG WITH THE
ENHANCED MOISTURE IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS
FOR THE REST OF THE GULF. A SURFACE TROUGH JUST W OF THE YUCATAN
PENINSULA ALONG 23N93W TO 19N94W IS ALSO SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS FROM 18N-23N BETWEEN 91W-96W. THIS TROUGH
IS EXPECTED TO CONTINUE TO DRIFT WNW OVER THE NEXT COUPLE OF
DAYS. THE SIGNIFICANT MOISTURE IS EXPECTED TO REMAIN OVER MUCH
OF THE GULF OF MEXICO WITH A LIKELY CHANCE OF SCATTERED
SHOWERS/THUNDERSTORMS.

CARIBBEAN SEA...
THE MAIN FEATURE IS A TROPICAL WAVE IN THE WESTERN CARIBBEAN.
SEE ABOVE THE TROPICAL WAVES SECTION. CONFLUENCE TO THE W OF AN
UPPER LEVEL INVERTED TROUGH WITH AXIS CENTERED NEAR 72W IS
GENERATING SHOWERS INLAND LA HISPANIOLA AND SCATTERED SHOWERS TO
THE CENTRAL CARIBBEAN W OF 68W. THE EASTERN CARIBBEAN IS UNDER
FAIR WEATHER CONDITIONS DUE TO DRY AIR SUBSIDENCE FROM A WEAK
UPPER LEVEL RIDGE CENTERED NEAR 60W. EXPECT SIMILAR WEATHER
CONDITIONS IN THE NEXT 24 HOURS.

ATLANTIC OCEAN...
SCATTERED SHOWERS/THUNDERSTORMS COVER THE FAR WRN ATLC
ASSOCIATED WITH HIGH MOISTURE VALUES AND UPPER LEVEL DIFFLUENCE
BETWEEN AN UPPER LEVEL TROUGH OVER THE ERN SEABOARD AND AN UPPER
LEVEL RIDGE EXTENDING FROM CUBA...TO THE NW BAHAMAS...TO 32N68W.
AN UPPER LEVEL LOW IN THE CENTRAL ATLC NEAR 28N50W IS SUPPORTING
SCATTERED SHOWERS FOR TWO SURFACE TROUGHS...ONE LOCATED FROM
30N50W TO 27N53W...THE SECOND TROUGH LOCATED FROM 26N43W TO
21N42W. TROPICAL STORM KATIA IS IMPACTING THE CENTRAL TROPICAL
ATLC. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. KATIA IS
EXPECTED TO MOVE WNW NEAR 17 KT. THE PAIR OF SURFACE TROUGHS ARE
ALSO EXPECTED TO MOVE WWD AROUND A SURFACE SUB-TROPICAL RIDGE IN
THE N CENTRAL ATLC.

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

$$
RAMOS







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