000 AXNT20 KNHC 271742 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON JUL 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 1645 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 41W/42W S OF 15N MOVING W NEAR 20 KT. THIS WAVE COINCIDES WITH A BROAD MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. ALSO...RECENT SATELLITE IMAGERY INDICATES CYCLONIC MOTION OF LOW LEVEL CLOUDS NEAR THIS WAVE. SCATTERED MODERATE CONVECTION IS FROM 8N-11N BETWEEN 39W-42W. A TROPICAL WAVE IS ALONG 65W/66W S OF 20N MOVING W NEAR 25 KT. THIS WAVE COINCIDES WITH A WELL-DEFINED MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. VISIBLE SATELLITE IMAGERY INDICATES AN INVERTED-V PATTERN IN THE COVERAGE OF LOW LEVEL CLOUDS NEAR THIS WAVE. STABLE ATMOSPHERIC CONDITIONS ASSOCIATED WITH AN UPPER LEVEL RIDGE ARE INHIBITING DEEP CONVECTION NEAR THIS WAVE. HOWEVER...SCATTERED MODERATE CONVECTION IS FROM 13N-16N BETWEEN 64W-67W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 10N27W 10N39W 9N50W 10N62W. SCATTERED MODERATE CONVECTION IS FROM 9N-14N BETWEEN 19W-23W. ...DISCUSSION... GULF OF MEXICO... A SHARP UPPER LEVEL TROUGH IS OVER THE CENTRAL AND W GULF WITH AN AXIS EXTENDING FROM 30N85W TO 20N96W. ATMOSPHERIC LIFT IN MOIST SOUTHWESTERLY FLOW ALOFT TO THE E OF THE UPPER LEVEL TROUGH AXIS...AND ATMOSPHERIC INSTABILITY NEAR THE UPPER LEVEL TROUGH...ARE SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE W GULF FROM 19N-25N BETWEEN 91W-98W. ADDITIONALLY...UPPER LEVEL MOISTURE STREAMING SOUTHWARD W OF THE UPPER LEVEL TROUGH IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE NW GULF N OF 27N W OF 91W. SOUTHEASTERLY WINDS ARE FORECAST TO INCREASE OVER THE W GULF BY TUESDAY...AS A SURFACE RIDGE ACROSS THE N GULF MOVES NORTHWARD DURING THE NEXT FEW DAYS AND SURFACE LOW PRESSURE DEVELOPS OVER W TEXAS. CARIBBEAN SEA... AN UPPER LEVEL HIGH IS OVER THE NW CARIBBEAN AND IS CENTERED NEAR 22N85W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS UPPER LEVEL RIDGE IS SUPPORTING SCATTERED SHOWERS FROM 18N-21N W OF 82W. ACROSS THE SW CARIBBEAN...UPPER LEVEL MOISTURE IS STREAMING NORTHWESTWARD FROM SHOWER AND THUNDERSTORM ACTIVITY OVER THE NEARBY E PACIFIC REGION. ACROSS MUCH OF THE CENTRAL AND E CARIBBEAN...DEEP LAYER DRY IS SUPPORTING GENERALLY FAIR WEATHER. HOWEVER...UPPER LEVEL DIFFLUENCE ASSOCIATED TO THE SW OF AN UPPER LEVEL RIDGE OVER THE CENTRAL ATLC IS SUPPORTING THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE OVER THE E CARIBBEAN ALONG 65W/66W S OF 20N. FRESH TO STRONG TRADE WINDS ARE OCCURRING ACROSS THE E AND CENTRAL CARIBBEAN S OF A SURFACE RIDGE OVER THE CENTRAL AND E ATLC. THE STRONGEST WINDS ARE FOUND NEAR THE COAST OF COLOMBIA...WHERE E WINDS OF 25 TO 30 KT WITH GUSTS TO GALE FORCE ARE OCCURRING. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS PRESENT OVER THE E UNITED STATES AND THE GULF OF MEXICO. ATMOSPHERIC LIFT IN MOIST SOUTHWESTERLY FLOW ALOFT BETWEEN THIS UPPER LEVEL TROUGH AND AN UPPER LEVEL RIDGE FARTHER TO THE E OVER THE SW NORTH ATLC IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N OF 25N BETWEEN 75W-79W INCLUDING PORTIONS OF THE FAR NW BAHAMAS. THIS ACTIVITY IS BEING SUPPORTED BY LOW LEVEL CONVERGENCE NEAR A SURFACE TROUGH EXTENDING FROM 27N79W TO 30N78W TO 32N77W TO N OF THE DISCUSSION AREA. TO THE E...AN UPPER LEVEL LOW IS CENTERED NEAR 32N58W. ATMOSPHERIC INSTABILITY IN THE VICINITY OF THIS UPPER LEVEL LOW...AND UPPER LEVEL DIFFLUENCE IN SOUTHWESTERLY FLOW ALOFT E OF THE LOW... ARE SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 27N BETWEEN 53W-62W. FARTHER TO THE E...SUBSIDENCE AND ATMOSPHERIC STABILITY ASSOCIATED WITH A DEEP LAYER RIDGE IS RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CENTRAL AND E ATLC. HOWEVER...A SURFACE TROUGH OVER THE E ATLC EXTENDS FROM A 1010 MB LOW NEAR 18N21W TO 20N19W TO THE W COAST OF AFRICA NEAR 22N16W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH. THE SURFACE LOW AND SURFACE TROUGH ARE LIKELY THE NORTHERN VORTICITY MAXIMUM ASSOCIATED WITH A TROPICAL WAVE THAT HAS LIKELY MOVED OFF THE W COAST OF AFRICA...CURRENTLY ANALYZED AS A SURFACE TROUGH EMBEDDED WITHIN THE ITCZ FROM 15N19W TO 8N17W. THIS SURFACE TROUGH EMBEDDED IS CURRENTLY ASSOCIATED WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS...AND RECENTLY SATELLITE IMAGERY INDICATES CYCLONIC MOTION OF LOW LEVEL CLOUDS NEAR THIS TROUGH. THIS TROUGH WILL LIKELY BE ANALYZED AS A TROPICAL WAVE ONCE ADDITIONAL DATA SUGGESTS ITS PRESENCE AS A TROPICAL WAVE. $$ COHEN