000 AXNT20 KNHC 271743 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED MAY 27 2009 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 1715 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 75W S OF 14N MOVING W 15-18 KT. WAVE POSITION BASED ON INTERPOLATION AS IT REMAINS DIFFICULT TO DEPICT ON VISIBLE SATELLITE IMAGERY. TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS SHOWS DECREASING MOISTURE AS THE WAVE CONTINUES WESTWARD MOVEMENT MAINLY ACROSS INLAND NRN COLOMBIA. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 7N11W 4N20W CROSSING THE EQUATOR NEAR 32W AND INTO NE BRAZIL NEAR 2S45W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S OF 6N BETWEEN 5W-26W. ELSEWHERE ISOLATED MODERATE CONVECTION IS S OF 5N BETWEEN 26W-38W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS MOVING ACROSS NORTH TEXAS SUPPORTING A COLD FRONT DRAPED FROM NE TEXAS THROUGH THE RIO GRANDE RIVER VALLEY. SCATTERED SHOWERS AND TSTMS ARE AHEAD OF THE FRONT NEAR THE TEXAS GULF COAST AND EXTEND N OF 27N W OF 93W IN THE NW GULF. SOUTHERLY WINDS OF 10 TO 15 KTS DOMINATE ACROSS THE GULF AHEAD OF THIS NEXT COLD FRONT WHICH IS POISED TO ENTER THE NW GULF EARLY MORNING THURSDAY. THE REMAINDER OF THE GULF IS EXPERIENCING RATHER TRANQUIL AND FAIR CONDITIONS THIS AFTERNOON WITH ONLY A FEW SCATTERED SHOWERS AND TSTMS OVER THE NE GULF FROM 26N-29N BETWEEN 85W-87W AS A RESULT OF WEAK LOW-LEVEL SURFACE WIND CONVERGENCE AND ATMOSPHERIC INSTABILITY. ALOFT...THE SRN GULF IS UNDER THE INFLUENCE OF AN UPPER RIDGE THAT EXTENDS NWD FROM THE E PACIFIC REGION AND MODERATELY DRY AND STABLE AIR S OF 27N. CARIBBEAN SEA... SURFACE HIGH PRESSURE IN THE W ATLC IS MAINTAINING STRONG E TO SE WIND FLOW ACROSS THE CARIBBEAN. THE SELY SURFACE FLOW ALONG WITH A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH ACROSS THE WRN CARIBBEAN N OF 17N BETWEEN 70W-80W IS GENERATING SCATTERED SHOWERS AND TSTMS ACROSS JAMAICA...THE WINDWARD PASSAGE... HISPANIOLA AND THE NEARBY COASTAL WATERS IN THE NRN CARIBBEAN N OF 16N BETWEEN 72W-81W. AN UPPER LEVEL DIFFLUENT PATTERN AROUND AN UPPER HIGH OVER THE E PACIFIC IS GENERATING SCATTERED SHOWERS AND TSTMS IN THE SW CARIBBEAN S OF 12N W OF 77W. THE NW CARIBBEAN REMAINS UNDER FAIR WEATHER CONDITIONS AS NW FLOW ALOFT PROVIDES A STABLE SUBSIDENT ATMOSPHERE. IN ADDITION...A TROPICAL WAVE IS OVER THE S/CENTRAL CARIBBEAN ALONG 75W. PLEASE SEE TROPICAL WAVE SECTION ABOVE FOR FURTHER INFORMATION. ATLANTIC OCEAN... A 1010 MB SURFACE LOW IS CENTERED NORTH OF THE DISCUSSION AREA IN THE W ATLC NEAR 33N75W. THIS LOW CONTINUES TO PROVIDE THE W ATLC S OF 32N WITH MOIST AND UNSTABLE SLY SURFACE WINDS UNDER A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH ACROSS FLORIDA AND THE W ATLC. ALL OF THESE FACTORS COMBINED ARE GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 23N-29N BETWEEN 74W-80W AND FROM THE NRN COASTS OF THE GREATER ANTILLES ISLANDS N OF 18N TO BEYOND 32N BETWEEN 65W-72W. THE LOW AND ASSOCIATED UPPER LEVEL TROUGH ARE FORECAST TO CONTINUE MOVING NORTH OVER THE NEXT 24 HOURS. FURTHER EAST...A RIDGE OF HIGH PRESSURE EXTENDS FROM NORTH OF THE REGION TO 20N BETWEEN 48W-65W. THE PRESENCE OF THIS SURFACE RIDGE IS LIMITING THE SWD EXTEND OF A COLD FRONT THAT LIES ALONG 33N BETWEEN 47W-60W. ACROSS THE CENTRAL ATLC...A SURFACE TROUGH IS ANALYZED FROM 23N47W ALONG 29N44W TO BEYOND 32N42W. SCATTERED SHOWERS ARE OBSERVED WITHIN 30 NM E OF THE SURFACE TROUGH AS A RESULT OF WEAK LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY. A SURFACE RIDGE IS PRESENT ACROSS THE E ATLC WITH FAIR WEATHER CONDITIONS N OF 7N E OF40W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH AN UPPER HIGH NEAR 8N25W IS ENHANCING CONVECTION ALONG THE ITCZ. $$ HUFFMAN