000 AXNT20 KNHC 171728 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT MAY 17 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 1645 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 33W S OF 11N MOVING W 10 KT. A LOW-AMPLITUDE INVERTED-V SIGNATURE IS OBSERVED ON VISIBLE SATELLITE IMAGERY. SIGNIFICANT CONVECTION NEAR THE WAVE AXIS IS ASSOCIATED WITH THE ITCZ. TROPICAL WAVE IS ALONG 54W S OF 11N MOVING W 10 KT. WAVE SIGNATURE IS DISTORTED AS IT MOVES INLAND OVER SOUTH AMERICA WITH NO ASSOCIATED SHOWERS/CONVECTION. TROPICAL WAVE IN THE SW CARIBBEAN ALONG 79W S OF 10N MOVING W NEAR 10 KT. MODERATE TO STRONG CONVECTION FROM 5N-8N BETWEEN THE WEST COAST OF COLOMBIA AND 81W. ..THE ITCZ... ITCZ AXIS IS CENTERED ALONG 5N7W 5N20W 4N30W 2N40W AND INTO NE BRAZIL NEAR 3N51W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3S-8N BETWEEN THE PRIME MERIDIAN AND 18W. SCATTERED MODERATE CONVECTION IS WITHIN 80 NM S OF THE AXIS BETWEEN 23W-26W. SIMILAR CONVECTION IS WITHIN 90 NM N OF THE AXIS BETWEEN 44W-49W. ...DISCUSSION... GULF OF MEXICO... A WEAK STATIONARY FRONT STRETCHES ACROSS THE GULF THIS AFTERNOON. AS OF 15Z...THE FRONT ENTERS THE REGION NEAR 28N83W...JUST NORTH OF TAMPA BAY...AND EXTENDS ALONG 26N90W TO NEAR 19N95W IN THE SOUTHERN BAY OF CAMPECHE. A THIN BAND OF LOW-LEVEL CLOUDS IS OBSERVED ALONG THE BOUNDARY. EXPECT THIS FRONT TO DISSIPATE DURING THE NEXT 24 HOURS. DOPPLER RADAR MOSAIC AND LIGHTNING DATA INDICATE NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS MOVING ACROSS THE GULF NW OF A LINE FROM VERACRUZ MEXICO TO THE MISSISSIPPI RIVER DELTA. THIS CONVECTION IS MOVING FAIRLY QUICKLY IN STRONG SWLY FLOW ALONG THE LEADING EDGE OF AN UPPER TROUGH. DRY...STABLE AIR AROUND AN UPPER HIGH OVER THE CARIBBEAN IS MAINTAINING MOSTLY CLEAR AND TRANQUIL CONDITIONS IN THE SE GULF. CARIBBEAN SEA... A SFC TROUGH...REMNANTS OF A FRONTAL BOUNDARY...EXTENDS ACROSS THE CARIBBEAN FROM THE VIRGIN ISLANDS...OVER THE SOUTHERN TIP OF HISPANIOLA...AND ACROSS JAMAICA TO NEAR 18N81W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE TROUGH. ISOLATED THUNDERSTORMS ASSOCIATED WITH A LOW OVER COLOMBIA ARE MOVING INTO THE SW CARIBBEAN S OF 11N AND E OF THE PANAMA CANAL...HOWEVER...DEEP CONVECTION IS LIMITED THROUGHOUT THE CARIBBEAN DUE TO STRONG SUBSIDENCE AROUND AN UPPER HIGH CENTERED NEAR 19N79W. UPPER LEVEL MOISTURE CONTINUES TO STREAM ACROSS THE SE CARIBBEAN AND OVER THE WINDWARD ISLANDS. LIGHT TO MODERATE TRADE WINDS PERSIST ACROSS THE REGION. ATLANTIC OCEAN... A STRONG LOW PRESSURE SYSTEM NORTH OF THE DISCUSSION AREA EXTENDS A COLD FRONT INTO THE TROPICAL N ATLC. AS OF 15Z...THE FRONT ENTERS THE REGION NEAR 31N73W AND CONTINUES ALONG 29N77W TO THE CENTRAL FLORIDA COAST NEAR MELBOURNE. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 120 NM AHEAD OF THE BOUNDARY N OF 29N. EAST OF THE FRONT...STRONG SW WINDS N OF 28N WILL WEAKEN TO 20 KT LATE. EXPECT THE FRONT TO MOVE RAPIDLY E AND DISSIPATE LATE TONIGHT. MOSTLY CLEAR CONDITIONS HAVE MOVED INTO THE W ATLC BEHIND THE FRONT. FARTHER EAST... A WEAKER COLD FRONT ENTERS THE CENTRAL ATLC NEAR 31N46W AND EXTENDS ALONG 25N50W TO 21N56W WHERE IT CONTINUES AS A SFC TROUGH OVER THE VIRGIN ISLANDS AND INTO THE CARIBBEAN SEA. LOW-LEVEL CLOUDS AND SCATTERED SHOWERS EXTEND UP TO 160 NM AHEAD OF THE COLD FRONT...AND WITHIN 60 NM OF THE SFC TROUGH. A LARGE SFC RIDGE ANCHORED BY A 1025 MB SFC HIGH SOUTH OF THE AZORES DOMINATES THE REMAINDER OF THE ATLC. AN UPPER RIDGE AXIS ELONGATED OVER THE TROPICS AROUND 10N IS ENHANCING CONVECTION IN THE ITCZ. $$ WADDINGTON