000 AXNT20 KNHC 152310 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON JUN 15 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 2245 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 77W S OF 17N MOVING W AROUND 15 KT. THIS WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. THIS WAVE IS ALSO ASSOCIATED WITH A MAXIMUM IN LOW LEVEL CYCLONIC CIRCULATION BASED ON COMPUTER MODEL GUIDANCE. SUBSIDENCE IN NORTHERLY FLOW ALOFT IS LIMITING THE COVERAGE OF DEEP CONVECTION NEAR THIS WAVE. HOWEVER... SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 240 NM E OF THE WAVE AXIS FROM 8N-12N INCLUDING PORTIONS OF N COLOMBIA. THIS CONVECTION IS BEING ENHANCED BY LOW LEVEL CONVERGENCE NEAR A 1012 MB SURFACE LOW OVER N COLOMBIA NEAR 9N74W. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 8N22W 6N30W 3N40W 1N51W. SCATTERED MODERATE CONVECTION IS FROM 11N-13N BETWEEN 18W-20W. SCATTERED MODERATE CONVECTION IS ALSO FROM 3N-8N BETWEEN 25W-32W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-6N BETWEEN 34W-39W. SCATTERED MODERATE CONVECTION IS FROM 1N-5N BETWEEN 40W-54W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH EXTENDS FROM THE S FLORIDA PENINSULA NEAR 26N81W TO W CUBA NEAR 23N83W. LOW LEVEL CONVERGENCE NEAR THIS TROUGH IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER W CUBA AND THE NEARBY COASTAL WATERS OF THE FAR SE GULF. ALSO...AN UPPER LEVEL TROUGH EXTENDS FROM THE BAY OF CAMPECHE SOUTHWESTWARD INTO THE E PACIFIC REGION. THIS UPPER LEVEL TROUGH IS ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM N OF THE YUCATAN PENINSULA NEAR 22N89W ACROSS THE BAY OF CAMPECHE TO 19N93W. LOW LEVEL CONVERGENCE AND ATMOSPHERIC INSTABILITY NEAR THESE FEATURES ARE SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE YUCATAN PENINSULA AND THE NEARBY COASTAL WATERS OF THE FAR S GULF. A SURFACE TROUGH CURRENTLY OVER THE W CARIBBEAN IS FORECAST TO MOVE INTO THE YUCATAN PENINSULA OVERNIGHT TONIGHT AND ACROSS THE SOUTHERN GULF TUESDAY AND WEDNESDAY... ACCOMPANIED BY SCATTERED THUNDERSTORMS. ELSEWHERE ACROSS THE GULF REGION...DEEP LAYER DRY AIR AND SUBSIDENCE IN CONFLUENT NORTHERLY FLOW ALOFT ARE RESULTING IN GENERALLY FAIR WEATHER. THE SUBSIDENCE IS SUPPORTING A 1017 MB SURFACE HIGH OVER THE CENTRAL GULF NEAR 27N89W. ANTICYCLONIC FLOW AROUND THE SURFACE HIGH IS AFFECTING MUCH OF THE GULF...WITH SE WINDS OF 15 TO 20 KT OCCURRING ACROSS PORTIONS OF THE W GULF IN RESPONSE TO A BROAD SURFACE TROUGH OVER MEXICO AND THE SOUTHERN PLAINS OF THE UNITED STATES. CARIBBEAN SEA... ACROSS THE W CARIBBEAN...A SURFACE TROUGH EXTENDS FROM 21N85W TO N HONDURAS NEAR 16N85W. THE ASCAT PASS AROUND 15/1600 UTC CONFIRMS CYCLONIC CURVATURE IN THE LOW LEVEL FLOW ACROSS THIS TROUGH. LOW LEVEL CONVERGENCE NEAR THIS TROUGH IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS FROM 12N-21N BETWEEN 80W AND 88W...INCLUDING PORTIONS OF HONDURAS AND NICARAGUA. THIS ACTIVITY IS BEING SUPPORTED BY DEEP LAYER MOISTURE AND UPPER LEVEL DIVERGENCE ASSOCIATED WITH AN UPPER LEVEL RIDGE OVER THE W CARIBBEAN. ADDITIONALLY...ATMOSPHERIC INSTABILITY IS RESULTING IN SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CUBA...HISPANIOLA...AND THE NEARBY COASTAL WATERS. THE SHOWER AND THUNDERSTORM ACTIVITY OVER W CUBA IS ALSO BEING SUPPORTED BY A SURFACE TROUGH THAT EXTENDS FROM W CUBA NEAR 23N83W NORTHEASTWARD INTO THE FAR SE GULF OF MEXICO. FARTHER TO THE E...SUBSIDENCE IN NORTHERLY FLOW ALOFT IS INHIBITING DEEP CONVECTION ACROSS MUCH OF THE E CARIBBEAN. HOWEVER...ATMOSPHERIC INSTABILITY NEAR AN UPPER LEVEL TROUGH OVER THE FAR E CARIBBEAN IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 14N E OF 67W INCLUDING PORTIONS OF PUERTO RICO AND THE LEEWARD ISLANDS. ATLANTIC OCEAN... ACROSS THE SW NORTH ATLC...A SURFACE TROUGH EXTENDS FROM 31N79W TO THE E FLORIDA PENINSULA NEAR 28N80W. LOW LEVEL CONVERGENCE NEAR THIS TROUGH IS INTERACTING WITH MOISTURE IN NORTHWESTERLY FLOW ALOFT TO RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS FROM 23N-29N W OF 75W INCLUDING PORTIONS OF THE NW BAHAMAS AND THE E FLORIDA PENINSULA. ALSO...UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 21N BETWEEN 63W-68W. ACROSS MUCH OF THE CENTRAL AND E ATLC...GENERALLY FAIR WEATHER IS PRESENT WHERE SUBSIDENCE IS OCCURRING NEAR A BROAD SURFACE RIDGE. HOWEVER...AN UPPER LEVEL TROUGH AXIS EXTENDS FROM 31N51W TO AN UPPER LEVEL LOW NEAR 27N50W TO 16N57W TO 11N57W. THE UPPER LEVEL LOW IS ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM 31N50W TO 29N51W TO 28N52W. THESE FEATURES ARE SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 14N-18N W OF 57W INCLUDING PORTIONS OF THE LEEWARD ISLANDS...AS WELL AS SCATTERED SHOWERS N OF 27N BETWEEN 44W-52W. ACROSS THE TROPICAL ATLC...A BROAD UPPER LEVEL RIDGE IS PRESENT WITH AN AXIS EXTENDING FROM 14N17W TO AN UPPER LEVEL HIGH NEAR 14N29W TO 9N47W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THESE FEATURES IS SUPPORTING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN