000
AXNT20 KNHC 111711
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 10 2008

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1645 UTC.

...SPECIAL FEATURE....

THE CENTER OF HURRICANE BERTHA AT 11/1500 UTC IS NEAR 28.5N 
62.0W...OR ABOUT 310 MILES SOUTH-SOUTHEAST OF BERMUDA. BERTHA IS 
MOVING SLOWLY NORTHWESTWARD OR 320 DEGREES AT 5 KT. THE 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 980 MB. BERTHA REMAINS A 
CATEGORY 1 HURRICANE ON THE SAFFIR-SIMPSON SCALE WITH MAXIMUM 
SUSTAINED WIND SPEEDS OF 75 KT WITH GUSTS TO 90 KT. LARGE SWELLS 
AND HIGH SURF CONTINUE TO AFFECT BERMUDA AND ARE EXPECTED TO 
PERSIST FOR THE NEXT FEW DAYS. SATELLITE IMAGERY DISPLAYS LITTLE 
CHANGE IN THE OVERALL CLOUD PATTERN SURROUNDING BERTHA. THIS 
DATA COMBINED WITH LOW WIND SHEAR SUGGEST THAT THE INTENSITY 
WILL NOT CHANGE GREATLY OVER THE NEXT FEW DAYS. AFTER 48 
HOURS...BERTHA IS EXPECTED TO ENCOUNTER INCREASED SHEAR AND 
COOLER WATERS... RESULTING IN GRADUAL WEAKENING. THE FIRST 
RECONNAISSANCE MISSION IS SCHEDULED FOR LATER TODAY. AT 1500 UTC 
THE BERMUDA WEATHER SERVICE HAS ISSUED A TROPICAL STORM WATCH 
FOR BERMUDA. INTERESTS IN THE ISLAND SHOULD CLOSELY MONITOR THE 
PROGRESS OF BERTHA DURING THE NEXT SEVERAL DAYS. PLEASE REFER TO 
THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER 
MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS.
 
...TROPICAL WAVES...

A WELL-DEFINED TROPICAL WAVE ALONG 40W/41W SOUTH OF 15N IS 
MOVING WEST AROUND 15 KT. AN INVERTED-V PATTERN AS WELL AS BROAD 
CYCLONIC TURNING ARE CLEARLY OBSERVED ON VISIBLE SAT. 
UPPER-LEVEL EASTERLY WINDS HAVE DISPLACED ASSOCIATED DEEP 
CONVECTION TO THE WEST OF THE AXIS...EMBEDDED WITHIN THE ITCZ. 
WIND DATA FROM THE THE LATEST QUIKSCAT PASS SUPPORT THE POSITION 
OF THE AXIS.

A TROPICAL WAVE IS ALONG 67W SOUTH OF 17N MOVING WEST AT 15 KT. 
MODERATE SUBSIDENCE OVER THE CENTRAL CARIBBEAN IS INHIBITING 
DEEP CONVECTION WITH THIS WAVE...HOWEVER CLUSTERS OF MODERATE TO 
STRONG CONVECTION ARE ALONG THE SOUTHERN EXTENT OF THE AXIS 
INLAND OVER VENEZUELA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N13W 6N25W 11N40W AND INTO SOUTH 
AMERICA NEAR 8N59W. SCATTERED MODERATE CONVECTION IS FROM 6N TO 
11N BETWEEN 16W AND 20W. SIMILAR CONVECTION IS WITHIN 90 NM OF 
THE AXIS BETWEEN 22W-25W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION IS FROM 4N TO 9N BETWEEN 26W-34W. SCATTERED MODERATE 
TO STRONG CONVECTION IS WITHIN 120 NM OF THE AXIS FROM 42W TO 
56W.

...DISCUSSION...

THE GULF OF MEXICO...
THE GULF IS FAIRLY TRANQUIL THIS AFTERNOON. EASTERLY FLOW AROUND 
THE SOUTHERN PERIPHERY OF AN E/W ELONGATED UPPER RIDGE BLANKETS 
THE REGION. UPPER LEVEL DIVERGENCE IS PROVIDING THE ONLY SOURCE 
OF CONVECTIVE ACTIVITY...ALLOWING A CLUSTER OF SCATTERED 
SHOWERS AND THUNDERSTORMS TO EMERGE IN THE SW BAY OF CAMPECHE 
BETWEEN VERACRUZ AND TAMPICO MEXICO. THE RIDGE IS TRANSPORTING 
UPPER LEVEL MOISTURE OVER THE EASTERN GULF E OF 88W. THE 
REMAINDER OF THE GULF IS MOSTLY CLEAR UNDER A DRY AND STABLE AIR 
MASS. AT THE SFC...A HIGH PRESSURE RIDGE EXTENDS FROM THE W ATLC 
ACROSS FLORIDA TO MEXICO...PROVIDING RETURN FLOW OF 10-15 KT 
ACROSS THE REGION. EXPECT A WEAK COLD FRONT TO ENTER N FLORIDA 
LATE SAT...BRINGING A CHANCE OF SCATTERED SHOWERS AND 
THUNDERSTORMS TO THE NE GULF.  

THE CARIBBEAN SEA...
A MID-UPPER LEVEL TROUGH EXTENDS FROM THE W ATLC OVER CUBA AND 
THE NW CARIBBEAN N OF 17N. AN UPPER RIDGE ANCHORED ON AN UPPER 
HIGH OVER THE SW CARIBBEAN IS S OF THE TROUGH. DIFFLUENT FLOW 
ASSOCIATED WITH THESE FEATURES IS ENHANCING SCATTERED MODERATE 
CONVECTION IN THE WESTERN CARIBBEAN BETWEEN 81W-86W S OF 20N. 
ONSHORE FLOW IS ALSO FUELING SCATTERED SHOWERS AND THUNDERSTORMS 
ALONG THE COAST OF NICARAGUA. ADDITIONAL CLUSTERS OF SHOWERS 
AND THUNDERSTORMS HAVE DEVELOPED IN RESPONSE TO LOW-LEVEL WIND 
SPEED CONVERGENCE IN THE SW CARIBBEAN S OF 12N. THE CENTRAL AND 
EASTERN CARIBBEAN REMAIN MOSTLY CLEAR DUE TO MODERATE SUBSIDENCE 
ALOFT. A TIGHT PRESSURE GRADIENT CONTINUES TO PRODUCE MODERATE 
TO STRONG TRADE WINDS ACROSS THE BASIN...WITH THE STRONGEST...UP 
TO 30 KT...ALONG THE COLOMBIAN COAST. 

THE ATLANTIC OCEAN...
A STATIONARY MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER  
NEAR 26N73W EXTENDS A TROUGH ACROSS THE W ATLC OVER CUBA AND 
INTO THE CARIBBEAN. A DEEP-LAYERED TROUGH N OF THE DISCUSSION 
AREA IS SUPPORTING A COLD FRONT AND AN ASSOCIATED BAND OF 
SHOWERS AND THUNDERSTORMS N OF 30N. WITH THE EXCEPTION OF 
HURRICANE BERTHA...A SURFACE RIDGE DOMINATES THE REMAINDER OF 
THE ATLC DISCUSSION AREA WITH A 1027 MB HIGH CENTERED NEAR 
32N33W. THIS SFC HIGH PAIRED WITH LOWER PRES OVER WESTERN AFRICA 
IS PRODUCING A SWATH OF MODERATE TO STRONG NE WINDS N OF 20N AND 
E OF 20W. FAIR-WEATHER CUMULUS CLOUDS FLOW AROUND THE RIDGE WITH 
NO SIGNIFICANT CONVECTION TO SPEAK OF.

$$
WADDINGTON