000 AXNT20 KNHC 271745 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN APR 27 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 7N10W 3N20W 2N30W 1N40W... CROSSING THE EQUATOR NEAR 50W...AND INTO NE BRAZIL. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM THE EQUATOR TO THE SW COAST OF AFRICA BETWEEN THE PRIME MERIDIAN AND 7W. SIMILAR CONVECTION IS ALSO FOUND WITHIN 120 NM N OF AXIS BETWEEN 25W AND 32W...AND FROM EQUATOR TO 3N AND WEST OF 41W. ...DISCUSSION... GULF OF MEXICO... AS OF 1500 UTC...A COLD FRONT IS MOVING ACROSS SOUTH TEXAS AND NORTHERN COAHUILA IN MEXICO. SATELLITE IMAGERY...DOPPLER RADAR AND LIGHTNING DATA SHOW AN AREA OF SHOWERS WITH EMBEDDED TSTMS OVER THE WESTERN GULF MAINLY N OF 23N AND WEST OF 90W. A LINE OF SHOWERS AND TSTMS IS JUST OFFSHORE SE LOUISIANA. A PRE-FRONTAL TROUGH IS ANALYZED OVER THE NW CORNER OF THE GULF AND THE DEEP SOUTH. A DIFFLUENT PATTERN ALOFT BETWEEN AN UPPER RIDGE COVERING THE ENTIRE GULF AND AN UPPER-LEVEL TROUGH OVER FOUR CORNER REGION AND NW MEXICO IS ENHANCING THIS CONVECTIVE ACTIVITY. THIS UPPER TROUGH ALSO SUPPORTS THE PREVIOUSLY MENTIONED COLD FRONT. A 1010 SFC LOW REMAINS OVER THE BAY OF CAMPECHE NEAR 19N94W WITH A SFC TROUGH EXTENDING MAINLY NWD TO NEAR 23N95W. THE COLD FRONT IS EXPECTED TO MOVE OFF THE TEXAS COAST LATE TODAY FOLLOWED BY STRONG NW WINDS OVER THE NW GULF. GALE FORCE WINDS ARE FORECAST TO BLOW OFF THE MEXICAN COAST IN THE SW GULF TONIGHT. AS A RESULT...A GALE WARNING IS ALREADY IN EFFECT. THE FRONT WILL EXTEND FROM NORTH FLORIDA TO THE BAY OF CAMPECHE MONDAY AFTERNOON AND MOVE SOUTHEAST OF THE AREA TUESDAY. A 1022 MB HIGH CENTERED NEAR 31N73W EXTENDS A RIDGE OVER THE REMAINDER OF THE GULF PRODUCING 10-15 KT SELY SURFACE WINDS DUE TO RETURN FLOW. CARIBBEAN SEA... LITTLE CHANGE HAS EXPERIENCED THE WEATHER PATTERN ACROSS THE CARIBBEAN SEA DURING THE LAST 24 HOURS. LIGHT TO MODERATE TRADEWINDS DOMINATES THE WESTERN CARIBBEAN WITH MOSTLY FAIR WEATHER W OF 75W THANKS TO THE PRESENCE OF A MID/UPPER LEVEL RIDGE AND IMPLIED DRY AIR MASS. BROKEN TO OVERCAST MULTILAYERED CLOUDS WITH SCATTERED SHOWERS...AND MODERATE TO FRESH WINDS ARE OVER THE E CARIBBEAN. THIS SHOWER ACTIVITY IS ASSOCIATED WITH A SFC TROUGH EXTENDING ALONG 67/68W ON THE 12Z MAP AND A MID/UPPER LEVEL TROUGH LOCATED OVER THE WEST-CENTRAL ATLC JUST N OF PUERTO RICO. STRONG SW TO WLY UPPER LEVEL FLOW IS ALSO HELPING TO INDUCE THIS CONVECTIVE ACTIVITY. THE SAN JUAN DOPPLER RADAR DEPICTS SCATTERED TO NUMEROUS SHOWERS AND TSTMS ALONG THE CORDILLERA CENTRAL MOVING NWD...AND ACROSS THE COASTAL WATERS PARTICULARLY ON THE ATLANTIC SIDE. A TROUGH...REMNANTS OF A COLD FRONT EXTENDS FROM THE LEEWARD ISLANDS NEWD ACROSS THE N TROPICAL ATLC. THIS FEATURE IS ALSO GENERATING CLOUDINESS AND SCATTERED SHOWERS. LOW-TOPPED TRADE WIND SHOWERS ARE MOVING ACROSS THE AREA. LOW-LEVEL WINDS FROM THE NE ARE ALSO ADVECTING PATCHES OF MOISTURE WITH EMBEDDED SHOWERS ACROSS THE ATLANTIC SIDE OF COSTA RICA. A 1008 MB LOW IS INLAND OVER N COLOMBIA NEAR 10N75W. WIDELY SCATTERED MODERATE CONVECTION IS RELATED TO THIS LOW. ACCORDING TO THE GFS MODEL...THE ATMOSPHERE WILL CONTINUE HUMID AND UNSTABLE OVER THE NE CARIBBEAN AT LEAST THIS AFTERNOON AND TONIGHT. THE SFC TROUGH ACROSS 67/68W WILL CONTINUE TO MOVE WWD REACHING JAMAICA MONDAY MORNING. ATLANTIC OCEAN... A RIDGE/TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE FORECAST AREA. A MID TO UPPER LEVEL TROUGH IS OVER THE WEST-CENTRAL ATLC WITH THE BASE OF THE TROUGH JUST NORTH OF DOMINICAN REPUBLIC AND PUERTO RICO. THE ATTENDANT COLD FRONT ENTERS THE AREA NEAR 31N45W THEN CONTINUES SW TO 22N53W. AT THIS POINT...A SFC TROUGH EXTENDS SW TO THE NORTHERN LEEWARD ISLANDS. A WIDE BAND OF MULTILAYERED CLOUDS WITH SCATTERED SHOWERS IS ASSOCIATED WITH THE FRONT. A 1022 HIGH PRES CENTERED NEAR 31N73W ALSO ENVELOPS THE STATE OF FLORIDA...CUBA...THE BAHAMAS AND THE WESTERN ATLC WITH MOSTLY FAIR WEATHER. ANOTHER RIDGE EXTENDING FROM A SFC HIGH SITUATED NEAR THE AZORES DOMINATES THE EASTERN ATLC. IN THE MIDDLE...THE AFOREMENTIONED COLD FRONT. WV IMAGERY AND CLOUD TRACKED WINDS INDICATE THE PRESENCE OF A BROAD UPPER LEVEL HIGH NEAR 8N50W. THIS FEATURE IS DOMINATING THE TROPICS MAINLY WEST OF 35W. AN UPPER-LEVEL TROUGH CROSSES BETWEEN THE CAPE VERDE ISLANDS AND THE WEST COAST OF AFRICA EXTENDING FROM AN UPPER LOW LOCATED NEAR 27N21W. $$ GR