000 AXNT20 KNHC 112340 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUN 11 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE ALONG 14N51W TO 3N54W IS MOVING W NEAR 15 KT. THIS HIGH AMPLITUDE WAVE HAS GAINED CONVECTION TODAY AS IT MOVED INTO AN UPPER DIFFLUENT ZONE. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM W AND 300 NM E OF THE AXIS. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N13W 5N24W 3N34W 3N45W 4N52W. SCATTERED MODERATE TO STRONG CONVECTION FROM 5N TO 10N BETWEEN 12W-25W. SCATTERED MODERATE CONVECTION IS FROM 2N-6N BETWEEN 27W-33W. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 39W-41W. ...DISCUSSION... GULF OF MEXICO... SFC HIGH PRES IS NEARLY STATIONARY CENTERED NEAR 27N87W PROVIDING LIGHT AND VARIABLE FLOW E OF 90W. SE WINDS INCREASE W OF 90W...STRONGEST (15-20 KT) OVER THE NW WATERS...DUE TO THE TIGHTENED PRES GRADIENT BETWEEN THE HIGH AND BROAD TROUGHING OVER S TEXAS AND MEXICO. FAIR WEATHER IS PRESENT ACROSS THE ENTIRE GULF SUPPORTED BY NLY FLOW ALOFT ON THE E SIDE OF A SPRAWLING MID-UPPER HIGH OVER CENTRAL MEXICO. LITTLE CHANGE IN THIS PATTERN IS EXPECTED OVER THE NEXT DAY OR TWO...SO MAINLY FAIR WEATHER IS FORECAST TO PERSIST. CARIBBEAN SEA... VISIBLE IMAGERY AND RECENT SCATTEROMETER DATA INDICATE BROAD SFC TROUGHING OVER THE WRN CARIBBEAN WITH A ROUGH AXIS EXTENDING FROM JAMAICA TO CENTRAL PANAMA. SFC OBSERVATIONS SHOW FAIRLY LOW PRESSURES...GENERALLY ABOUT 1-2 MB LOWER THAN THIS TIME YESTERDAY. SCATTERED MODERATE CONVECTION IS LOCATED TO THE E OF THE SFC TROUGH...WITHIN AN UPPER DIFFLUENT AREA E OF AN UPPER TROUGH AXIS THAT EXTENDS FROM CENTRAL CUBA TO NICARAGUA. SCATTERED MODERATE CONVECTION IS CURRENTLY LOCATED S OF 12N BETWEEN 75W-82W AND N OF 14N BETWEEN 72W AND 76W. THE ERN CARIBBEAN IS EXPERIENCING FAIR WEATHER...THOUGH SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER PUERTO RICO AND THE VIRGIN ISLANDS ASSOCIATED WITH THE AFOREMENTIONED DIFFLUENT ZONE. MOISTURE IS EXPECTED TO INCREASE OVER THE LESSER ANTILLES LATE TOMORROW AND SAT AS A TROPICAL WAVE APPROACHES THE AREA. ATLANTIC OCEAN... UPPER LEVEL DIFFLUENCE IN MOIST SOUTH-SOUTHWESTERLY FLOW ALOFT ACROSS THE SW NORTH ATLC IS OCCURRING E OF AN UPPER LOW NE OF THE BAHAMAS. THIS IS PROVIDING THE SUPPORT FOR SCATTERED SHOWERS AND THUNDERSTORMS N OF 19N BETWEEN 62W-74W INCLUDING PORTIONS OF HISPANIOLA. THIS ACTIVITY IS ALSO BEING SUPPORTED BY LOW LEVEL CONVERGENCE NEAR A SURFACE TROUGH EXTENDING FROM 29N65W TO 29N74W. THE ASCAT PASS AROUND 11/1400 UTC CONFIRMS A CYCLONIC WIND SHIFT ACROSS THIS TROUGH. FARTHER TO THE W...SUBSIDENCE IN DRY NORTHERLY FLOW ALOFT IS SUPPORTING GENERALLY FAIR WEATHER ACROSS WESTERN PORTIONS OF THE SW NORTH ATLC. FARTHER TO THE E...GENERALLY FAIR WEATHER IS PRESENT ACROSS MUCH OF THE CENTRAL AND E ATLC WHERE SUBSIDENCE IS OCCURRING NEAR A BROAD SURFACE RIDGE. THIS SURFACE RIDGE IS ANCHORED BY A 1025 MB SURFACE HIGH NEAR 29N36W. HOWEVER...ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL TROUGH WITH AN AXIS FROM 18N49W TO 27N36W TO 32N31W TO NE OF THE DISCUSSION AREA IS SUPPORTING SCATTERED SHOWERS FROM 19N-23N BETWEEN 48W-52W AND N OF 25N BETWEEN 25W-31W. ACROSS THE TROPICAL ATLC...A BROAD UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 12N24W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS FEATURE IS SUPPORTING CONVECTION ASSOCIATED WITH THE ITCZ. $$ CANGIALOSI/COHEN