[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261212
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI AUG 26 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...
TROPICAL STORM KATRINA WAS UPGRADED AGAIN AT 0900 UTC TO
HURRICANE AFTER ENTERING THE GULF OF MEXICO. HURRICANE KATRINA
IS CENTERED NEAR 25.3N 81.8W OR ABOUT 50 MILES NORTH OF KEY WEST
AND ABOUT 60 MILES SOUTH OF NAPLES FLORIDA AT 26/1100 UTC...
MOVING WEST AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
987 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO
80 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER HEADERS
MIATCPAT1/WTNT32 KNHC FOR MORE DETAILS. STRONG CONVECTION HAS
SPREAD SW AHEAD OF THE CENTER WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS DOTTING THE BAHAMAS. SCATTERED/ NUMEROUS STRONG
CONVECTION IS ALONG THE FLORIDA W COAST WITHIN A 45 NM RADIUS OF
25N81W THIS INCLUDES THE FLORIDA KEYS. SCATTERED MODERATE/STRONG
CONVECTION COVERS THE REMAINDER OF THE AREA ACROSS W CUBA FROM
21N-24N BETWEEN 81W-85W AND SCATTERED MODERATE/ISOLATED STRONG
CONVECTION OVER THE STRAITS OF FLORIDA AND THE S FLORIDA
PENINSULA FROM 23N-27N BETWEEN 78W-82.5W INCLUDING LAKE
OKEECHOBEE.

A 1008 MB LOW IS CENTERED NEAR 17.5N46W MOVING NW NEAR 10 KT.
THIS LOW HAS THE POTENTIAL FOR FURTHER DEVELOPMENT...HOWEVER AN
MID/UPPER LEVEL INVERTED TROUGH IS JUST TO THE W OF THE SURFACE
LOW. THIS TROUGH HAS BEEN TRACKING W WITH THE SURFACE LOW THUS
PROVIDING A SHEAR ENVIRONMENT HAMPERING FURTHER DEVELOPMENT.
ASSOCIATED DEEP CONVECTION IS NE OF THE CENTER. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 20.5N-23.5N BETWEEN 45W-48W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 15N-21N BETWEEN 42W-49W.

...TROPICAL WAVES...
ATLC TROPICAL WAVE IS ALONG 35W/36W S OF 17N MOVING W 10 KT.
MID LEVEL CYCLONIC TURNING IS OBSERVED ON INFRARED SATELLITE
IMAGERY S OF 15N. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 11N-15N BETWEEN 33W-39W.

CARIBBEAN TROPICAL WAVE IS ALONG 83W S OF 21N MOVING W 15-20 KT.
WAVE SIGNATURE CURVATURE IS OBSERVED OVER THE SW CARIBBEAN.
SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 11N-17N BETWEEN 83W-86W
MOSTLY ALONG THE COAST OF NICARAGUA AND HONDURAS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 15N16W 10N32W 15N43W THEN ALONG
14N48W 10N63W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 200 NM N OF THE AXIS BETWEEN 23W-32W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 250 NM S OF
THE AXIS BETWEEN 29W-39W AND WITHIN 180 NM OF THE AXIS FROM
45W-51W.

...DISCUSSION...
GULF OF MEXICO...
THE MAIN WEATHER INTEREST THIS MORNING CONTINUES TO BE HURRICANE
KATRINA MOVING OFF S FLORIDA INTO THE GULF OF MEXICO. SEE
SPECIAL FEATURES ABOVE. ELSEWHERE...A NARROW UPPER LEVEL
INVERTED TROUGH IS OVER THE W BAY OF CAMPECHE ALONG 95W S OF 26N
DRAWING MOISTURE AND SHOWERS FROM OVER S MEXICO INTO THE CENTRAL
BAY OF CAMPECHE ALONG THE IMMEDIATE COAST. REMAINDER OF THE GULF
IS UNDER E UPPER FLOW FROM AN UPPER HIGH ANCHORED OVER N
LOUISIANA...COVERING THE SE UNITED STATES...GULF OF MEXICO...NW
CARIBBEAN...AND PORTIONS OF THE W ATLC. THERE ARE NO SURFACE
FEATURES IN THE GULF OTHER THAN HURRICANE KATRINA AND A TROPICAL
WAVE.

THE CARIBBEAN SEA...
CONVECTION FROM HURRICANE KATRINA EXTENDS ACROSS W CUBA INTO THE
NW CARIBBEAN. UPPER LEVEL HIGH ANCHORED OVER N LOUISIANA IS
PRODUCING ANTICYCLONIC FLOW OVER NW CARIBBEAN N OF 12N W OF 70W.
NE TO E UPPER LEVEL WINDS DOMINATE MOST OF THE CARIBBEAN EXCEPT
IN THE NE WHERE A RIDGE AXIS FROM THE LEEWARD/VIRGIN ISLANDS TO
INTO THE CENTRAL ATLC. THERE ARE NO SURFACE FEATURES IN THE
CARIBBEAN OTHER THAN A TROPICAL WAVE. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS WITHIN 75 NM OF LINE FROM E
JAMAICA SW TO 15N79W. IS OVER THE BAY ON GONAVE AND ALONG THE
COAST OF HAITI. SIMILAR CONVECTION IS WITHIN 45 NM OF LINE
19N80W TO THE COAST OF HONDURAS NEAR 16N84W.

THE ATLANTIC OCEAN...
ASSOCIATED DEEP CONVECTION ASSOCIATED WITH HURRICANE KATRINA IS
W OF THE N BAHAMA ISLANDS TO INLAND OVER FLORIDA. ISOLATED
SHOWERS REMAIN OVER W GRAND BAHAMA AND ANDROS ISLANDS. BROAD
UPPER RIDGE ANCHORED BY AN UPPER LEVEL HIGH OVER N LOUISIANA
COVERS THE W ATLC W OF 70W. KATRINA IS EMBEDDED WITHIN THIS
FLOW. AN UPPER LEVEL TROUGH THAT CONTINUES TO DIG SOUTH HAS
MERGED WITH A UPPER LOW AND NOW EXTENDS S TO 24N BETWEEN
60W-70W. MID/UPPER LEVEL RIDGE FROM THE NE CARIBBEAN EXTENDS
ACROSS THE LEEWARD AND VIRGIN ISLANDS TO NEAR 26N60W. THE
DIFFLUENCE OVER THE W ATLC IS GENERATING SCATTERED CLUSTERS OF
SCATTERED MODERATE TO SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ACROSS THE AREA W OF 60W. SCATTERED MODERATE/STRONG
CONVECTION IS FROM OVER THE TURKS AND CAICOS TO OVER HISPANIOLA.
AN UPPER HIGH IN THE CENTRAL ATLC IS CENTERED NEAR 31N55W
EXTENDING S TO NEAR 24N FROM 48W-60W. THE E ATLC IS DOMINATED BY
A MID/UPPER LEVEL RIDGE THAT EXTENDS OFF AFRICA ALONG 18N TO AN
UPPER HIGH NEAR 17N38W TO 12N52W. THE FIRST VISIBLE SATELLITE
IMAGES REVEAL AFRICAN DUST FROM 13N-23N MOVING ACROSS THE CAPE
VERDE ISLAND TO NEAR 40W. AT THE SURFACE...SUBTROPICAL RIDGE IS
ANCHORED OVER THE NE ATLC BY A 1028 NM HIGH JUST W OF THE
AZORES.

$$
WALLACE



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