[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 291749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUL 29 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURE...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 43W/44 SOUTH OF 15N
MOVING WEST 20 KT. A 1011 MB LOW PRESSURE CENTER IS ALONG THE
WAVE FROM 8N TO 9N. ONLY ISOLATED MODERATE CONVECTION IS
ASSOCIATED WITH THE LOW/WAVE. WHILE THE ASSOCIATED SHOWER
ACTIVITY HAS DECREASED THIS MORNING...THERE IS STILL POTENTIAL
FOR DEVELOPMENT...AND A TROPICAL DEPRESSION COULD FORM DURING
THE NEXT DAY OR TWO AS THE SYSTEM MOVES WESTWARD AT ABOUT 20 MPH.

...TROPICAL WAVES...

VERY ACTIVE TROPICAL WAVE IS ALONG 66W/67W SOUTH OF 20N MOVING
WEST 20 KT. CLUSTERS OF MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 14N-18N BETWEEN 65W-72W. THE WAVE IS CURRENTLY MOVING
ACROSS PUERTO RICO AND WILL CROSS DOMINICAN REPUBLIC THIS
AFTERNOON AND TONIGHT...BRINGING AN INCREASE IN SHOWER AND TSTM
ACTIVITY TO THAT AREA. THE WAVE IS ALSO HELPING TO ENHANCE THE
SHOWER/TSTM ACTIVITY OVER WESTERN VENZUELA. GUADELOUPE IN THE
LESSER ANTILLES REPORTED 1.92 INCHES OF RAIN WITH THE PASSAGE OF
THE TROPICAL WAVE WHILE THE SAN JUAN DOPPLER RADAR ESTIMATED
RAINFALL AMOUNTS OF 2 TO 3 INCHES OVER ST. CROIX IN THE U.S.
VIRGIN ISLANDS EARLY THIS MORNING. ALTHOUGH SHOWER ACTIVITY HAS
INCREASED THIS MORNING IN ASSOCIATION WITH THIS TROPICAL WAVE
THERE ARE NO SIGNS OF ORGANIZATION...AND ADDITIONAL
DEVELOPMENT...IF ANY...SHOULD BE SLOW TO OCCUR.

A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 82W/83W SOUTH OF
21N MOVING WEST 20 KT. WIDELY SCATTERED MODERATE CONVECTION IS
JUST AHEAD OF THE WAVE AXIS OVER THE NW CARIBBEAN AND THE GULF
OF HONDURAS. A CLUSTER OF SCATTERED MODERATE CONVECTION IS OVER
THE SW CARIBBEAN BEHIND THE WAVE AXIS FROM 11N-13N BETWEEN
79W-81W. SHOWERS AND THUNDERSTORMS ARE SOUTH OF 10N IN THE GULF
OF URABA OF COLOMBIA...PROBABLY MORE RELATED TO THE ITCZ THAN TO
THIS WAVE. THIS FEATURE IS EXPECTED TO ENHANCE THE SHOWER/TSTM
ACTIVITY OVER N CENTRAL AMERICA THIS AFTERNOON AND TONIGHT.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N17W 12N-30W 9N43W 7N58W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG THE COAST
OF W AFRICA AND THE COASTAL WATERS FROM 5N-13N. SIMILAR
CONVECTION IS WITHIN 80/100 NM NORTH OF THE ITCZ AXIS BETWEEN
47W-55W.

...DISCUSSION...
THE GULF OF MEXICO...
AN UPPER RIDGE EXTENDS ALONG THE NORTHER GULF WATERS AND THE SE
OF THE U.S. MIDDLE TO UPPER LEVEL LOW CENTERS ARE IN THE WESTERN
PORTION OF THE BAY OF CAMPECHE AND OVER THE NE CORNER OF THE
GULF. A SURFACE TROUGH...REFLECTION OF THE SECOND UPPER LOW RUNS
FROM 27N-83W TO 23N-85W. SCATTERED SHOWERS WITH EMBEDDED TSTMS
ARE ASSOCIATED WITH THE SURFACE TROUGH. SIMILAR CONVECTIVE
ACTIVITY IS OVER THE W BAY OF CAMPECHE. A 1012 MB SURFACE HIGH
IS OVER ALABAMA WITH A RIDGE EXTENDING WWD TO EASTERN TEXAS.
BROAD 10-15 SELY FLOW DOMINATES THE GULF OF MEXICO. A RIDGE WILL
PERSIST ACROSS THE NORTHERN GULF DURING THE NEXT FEW DAYS.

THE CARIBBEAN SEA...
THE MAIN FEATURE ACROSS THE BASIN IS THE TROPICAL WAVE AFFECTING
PUERTO RICO AND DOMINICAN REPUBLIC. SEE TROPICAL WAVES SECTION.
AN UPPER HIGH IS LOCATED OVER THE GULF OF HONDURAS WHILE ANOTHER
ONE IS JUST EAST OF THE LEEWARD ISLANDS...SUPPORTING THE
DEVELOPMENT OF THE CONVECTIVE ACTIVITY RELATED TO THE ABOVE
MENTIONED TROPICAL WAVE. IN THE MIDDLE...THERE IS AN UPPER
TROUGH THAT EXTENDS FROM A LOW LOCATED NORTH OF THE BAHAMAS TO
OVER CUBA AND THE CAYMAN ISLANDS. CONSIDERABLE UPPER LEVEL
MOISTURE COVERS THE CARIBBEAN SEA. 10-20 KT TRADE WINDS BLOW
OVER MUCH OF THE AREA.

THE ATLANTIC OCEAN...
A SURFACE RIDGE GOES FROM 1021 MB HIGH PRESSURE CENTER LOCATED
NEAR 33N-31W TO NORTH FLORIDA AND THE SE U.S. WHERE THERE IS A
SECONDARY CENTER WITH THE SAME CENTRAL PRESSURE VALUE. SCATTERED
PATCHES OF LOW LEVEL CLOUDS ARE FROM 20N-31N EAST OF 60 W.
DOPPLER RADAR SHOWS SCATTERED SHOWERS WITH EMBEDDED TSTMS ACROSS
SOUTH FLORIDA AND THE SURROUNDING COASTAL WATERS. IN THE UPPER
LEVELS...MIDDLE/UPPER LEVEL LOW CENTER IS JUST NORTH OF THE
BAHAMAS NEAR 25N74W. A HIGH IS JUST EAST OF THE LEEWARD ISLANDS
NEAR 18N61W. AN UPPER RIDGE IS ALSO OVER THE E/CENTRAL
ATLC...WITH THE RIDGE AXIS ALONG 20N. MODERATE TO STRONG
SUBSIDENCE IS FOUND OVER MUCH OF THE ATLC N OF 15N EAST OF 60W.

$$
GR



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