[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 260602
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...
HURRICANE KATRINA MADE LANDFALL AROUND 630 PM EDT BETWEEN
HALLANDALE BEACH AND NORTH MIAMI BEACH FLORIDA. SHORTLY AFTER
800 PM THE NATIONAL HURRICANE CENTER WAS IN THE EYE OF KATRINA.
AT 26/0100 UTC HURRICANE KATRINA WAS DOWNGRADED TO TROPICAL
STORM. KATRINA IS CENTERED NEAR 25.4N 81.3W OR ABOUT 40 MILES...
35 NM SSE OF MARCO ISLANDS FLORIDA AND 65 MILES...55 NM NE OF
KEY WEST FLORIDA AT 25/0600 UTC MOVING SOUTHWEST AT 7KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 984 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. RADAR SHOWS THE STRONGEST THUNDERSTORMS ARE S AND
E OF THE CENTER. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN
45 NM OF LINE FROM THE COAST OF CUBA 23N82W TO OVER THE FLORIDA
KEYS TO 25N80W. SCATTERED MODERATE/STRONG CONVECTION COVERS THE
REMAINDER OF THE AREA FROM 21N-27N BETWEEN 78W-83W...WHICH IS S
OF LAKE OKEECHOBEE TO OVER CUBA BETWEEN THE N BAHAMA ISLANDS
INTO THE SE GULF INCLUDING ALL OF THE FLORIDA KEYS. UPPER LEVEL
OUTFLOW IS GENEROUS IN ALL QUADRANTS. KATRINA WILL CONTINUE
ACROSS S FLORIDA AND EMERGE IN THE GULF OF MEXICO LATER THIS
MORNING.

A 1009 MB LOW IS CENTERED NEAR 17N45.5W MOVING W NEAR 10 KT.
THIS LOW HAS THE POTENTIAL FOR FURTHER DEVELOPMENT...HOWEVER AN
UPPER LEVEL INVERTED TROUGH IS JUST TO THE W OF THE SURFACE LOW.
THIS UPPER TROUGH HAS BEEN TRACKING W WITH THE SURFACE LOW THUS
PROVIDING A SHEAR ENVIRONMENT HAMPERING FURTHER DEVELOPMENT.
ASSOCIATED DEEP CONVECTION IS WELL TO THE N AND E OF THE CENTER.
SCATTERED STRONG CONVECTION IS FROM 18.5N-21.5N BETWEEN 44W-47W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 16N-19N
BETWEEN 40W-43W.

...TROPICAL WAVES...
ATLC TROPICAL WAVE IS ALONG 34W/35W S OF 17N MOVING W 10-15 KT.
MID LEVEL CYCLONIC TURNING IS OBSERVED ON INFRARED SATELLITE
IMAGERY S OF 14N. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS WITHIN 60 NM OF 13N FROM 33W-36W.

CARIBBEAN TROPICAL WAVE IS ALONG 80W/81W S OF 21N MOVING W 15-20
KT. WAVE SIGNATURE CURVATURE IS MASKED BY HIGH LEVEL DEBRIS
CLOUDS AND MODERATE EASTERLY FLOW. NO ASSOCIATED DEEP
CONVECTION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 16N16W 9N31W 14N43W THEN ALONG
13N48W 10N55W 10N63W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE WITHIN 180 NM OF THE AXIS BETWEEN 21W-43W.

...DISCUSSION...
GULF OF MEXICO...
THE MAIN WEATHER INTEREST EARLY THIS MORNING IS TROPICAL STORM
KATRINA MOVING ACROSS S FLORIDA AND WILL EMERGE INTO THE SE GULF
WITH THE NEXT FEW HOURS. SEE SPECIAL FEATURES ABOVE.
ELSEWHERE...A NARROW UPPER LEVEL INVERTED TROUGH IS OVER THE
CENTRAL BAY OF CAMPECHE ALONG 93W S OF 23N DRAWING MOISTURE AND
SHOWERS/ THUNDERSTORMS FROM OVER GUATEMALA AND S MEXICO INTO THE
E BAY OF CAMPECHE S OF 20N E OF 93W. 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. AT THE SURFACE...A WEAK
1015 MB HIGH IS IN THE W GULF NEAR 24N95W.

THE CARIBBEAN SEA...
THE SOUTHERN MOST FEEDER BAND OF TROPICAL STORM KATRINA EXTENDS
OVER W CUBA. UPPER LEVEL HIGH ANCHORED OVER N LOUISIANA IS
PRODUCING ANTICYCLONIC FLOW OVER NW CARIBBEAN N OF 14N W OF 70W.
NE TO E UPPER LEVEL WINDS DOMINATE MOST OF THE CARIBBEAN EXCEPT
IN THE NE WHERE A RIDGE AXIS FROM NEAR 17N63W NW ACROSS THE
LEEWARD/VIRGIN ISLANDS TO 25N60W IN THE CENTRAL ATLC. THERE ARE
NO FEATURES IN THE CARIBBEAN OTHER THAN A TROPICAL WAVE.
SCATTERED MODERATE/STRONG CONVECTION IS INLAND AND WITHIN 75 NM
ALONG THE COAST FROM 72W-76W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION 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 TROPICAL STORM
KATRINA IS W OF THE N BAHAMA ISLANDS TO INLAND OVER FLORIDA.
ISOLATED SHOWERS REMAIN OVER THE BAHAMA ISLANDS N OF CROOKED
ISLAND PASSAGE. BROAD DUPER 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 IS DIGGING S
INTO THE W ATLC N OF 30N FROM 63W-72W WITH A COLD FRONT
EXTENDING SW THROUGH BERMUDA TO 31N69W. A SECOND UPPER LOW IS
JUST TO THE S NEAR 27N64W. A MID/UPPER LEVEL RIDGE FROM THE NE
CARIBBEAN EXTENDS ACROSS THE LEEWARD AND VIRGIN ISLANDS TO NEAR
25N60W. 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. AN UPPER HIGH IN THE
CENTRAL ATLC IS CENTERED NEAR 31N56W EXTENDING S TO NEAR 25N
FROM 48W-60W. THE E ATLC IS DOMINATED BY A MID/UPPER LEVEL RIDGE
THAT EXTENDS OFF AFRICA ALONG 18N TO NEAR 45W. THE LAST VISIBLE
SATELLITE IMAGES REVEAL AFRICAN DUST MOVING ACROSS THE CAPE
VERDE ISLAND TO NEAR 30W. AT THE SURFACE...SUBTROPICAL RIDGE IS
ANCHORED OVER THE NE ATLC BY A 1029 NM HIGH JUST W OF THE
AZORES.

$$
WALLACE


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