000 AXNT20 KNHC 051730 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU JUL 05 2007 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 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ADDED TO 12Z ANALYSIS HIGHLY TITLED ALONG 4N28W 11N26W 16N21W ESTIMATED TO BE MOVG W 10-15 KT. THE DAKAR UPPER AIR TIME SECTION SHOWED A DISTINCT WAVE PASSAGE LATE JUNE 2ND/EARLY JUNE 3. THIS BROAD WAVE CONTAINS AN AREA OF LOW-LEVEL TURNING IN THE VICINITY OF 10N27W WELL DEPICTED BY A PAIR OF SURROUNDING SHIP OBS. IN ADDITION...THESE OBS ALSO INDICATE THAT THERE IS SLIGHTLY LOWER PRES NEAR THE ANALYZED AXIS AS COMPARED WITH SFC OBS TO IT'S E AND ALONG THE W AFRICAN COAST. A LARGER SCALE INVERTED V-TYPE STRUCTURE IS APPARENT FURTHER TO THE NE...WHICH WAS THE REASON FOR SLOPING THE WAVE IN THAT DIRECTION. MINIMAL SHOWER ACTIVITY IS ASSOCIATED WITH THIS FEATURE. A 1014 MB LOW PRES SYSTEM CENTERED NEAR 11N49W IS MOVING W 10-15 KT. THIS WEAK LOW CONTINUES TO HAVE MINIMAL TSTM ACTIVITY CONFINED TO THE SRN SEMICIRCLE. VIS IMAGERY TODAY HAS SHOWN THAT THE CIRCULATION APPEARS OPEN AT TIMES...SO TO BETTER FIT THE OVERALL STRUCTURE A TROPICAL WAVE WILL BE ADDED ALONG THE LOW AT 18Z. THAT THE WEAK LOW IS MORE ELONGATED AND MAY NOT BE ENTIRELY CLOSED ANY LONGER...SO A TROPICAL WAVE WILL BE ADDED ALONG THE LOW AT 18Z TO BETTER FIT THE OVERALL STRUCTURE OF THIS FEATURE. A TROPICAL WAVE IS TITLED ALONG 61W/62W MOVING W NEAR 15 KT. ASSOCIATED SCATTERED SHOWERS ARE OVER THE SRN WINDWARD ISLANDS AND OVER PORTIONS OF LEEWARD ISLANDS. HOWEVER...DEEP MOISTURE REMAINS LIMITED LIKELY CAPPED BY THE STRONGLY SUBSIDENT ENVIRONMENT THAT IT IS ENTRENCHED IN. OVERALL...THE STRUCTURE OF THE WAVE IS LESS DEFINED TODAY WITH THE PSN BASED MOSTLY A PERTURBATION IN THE ITCZ AND 24-H PRES TENDENCIES. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 7N25W 4N36W 6N50W 8N60W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 120 NM S OF THE AXIS BETWEEN 15W-22W AND WITHIN 90 NM N OF AXIS BETWEEN 30W-34W. ...DISCUSSION... GULF OF MEXICO... SHOWERS AND TSTMS CONTINUE TO AFFECT PORTIONS OF THE NW GULF...LOUISIANA AND E TEXAS. THE COMBINATION OF UPPER DIFFLUENCE...BETWEEN AN UPPER LOW OVER NRN MEXICO AND AN UPPER HIGH OVER THE N CENTRAL GULF...AND A TROUGH OF LOW PRES ARE THE CULPRITS IN PRODUCING THE ACTIVITY HERE OVER AT LEAST THE PAST FEW DAYS. IN THE E GULF...A WEAK SFC TROUGH HANGS WSW FROM A 1015 MB LOW NEAR SARASOTA FLORIDA TO 26N87W. MOST OF THE DYNAMICS PRODUCING TSTM ACTIVITY LIES OFF THE E COAST OF FLORIDA...MORE ON THIS IN THE ATLC SECTION. TIGHTENED PRES GRADIENT BETWEEN HIGH PRES OVER THE SE STATES AND LOWER PRES OVER TEX/MEX IS PRODUCING MODERATE SELY WINDS ACROSS THE SW GULF. THE UPPER FLOW IS PREDOMINATELY N-NELY CAUGHT BETWEEN AN UPPER RIDGE OVER THE EPAC AND AN UPPER LOW OVER THE NW CARIB. THIS FLOW IS ADVECTING BROKEN HIGH LEVEL CLOUDINESS ACROSS THE BULK OF THE AREA. CARIBBEAN SEA... A SURGE OF DRY AIR ALOFT CONTINUES TO PROPAGATE W ACROSS THE CARIB ADVECTED TO ABOUT 82W FROM THE TROPICAL ATLC. THIS STABLE AIRMASS IS PROVIDING FAIR WEATHER ACROSS MUCH OF THIS REGION. THE EXCEPTION IS OVER THE LESSER ANTILLES WHERE PATCHY SHOWER ACTIVITY IS AFFECTING THE SRN WINDWARDS AND NRN LEEWARDS ASSOCIATED WITH A TROPICAL WAVE IN THE VICINITY. THE UPPER ATMOSPHERE IS MORE MOIST FURTHER W SUPPORTED BY AN UPPER LOW SPINNING OVER GUATEMALA. BUT EVEN HERE...DEEP MOISTURE IS CONFINED TO THE EXTREME SW CARIB AND OVER PANAMA...COSTA RICA AND SRN NICARAGUA ENHANCED BY THE ITCZ. A SMALLER LESS DEFINED UPPER LOW HAS BEEN NEARLY STATIONARY OVER THE PAST COUPLE DAYS ABOVE THE WINDWARD PASSAGE. INSTABILITY NEAR THIS LOW PRODUCED A BRIEF BURST OF CONVECTION THIS MORNING BUT THIS HAS COMPLETELY FIZZLED WITH ONLY A FEW SHOWERS LEFTOVER. AT THE SFC...A 1058 Z QSCAT PASS SHOWED A LARGE AREA OF 20-30 KT ELY TRADES ACROSS THE REGION FROM 11N-18N...STRONGEST NEAR THE COAST OF COLOMBIA. ATLANTIC OCEAN... A STALLED FRONT CLIPS THE AREA ALONG 32N52W 30N65W WITH A WEAK LOW POSSIBLY FORMING ALONG IT'S TAIL. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 60 NM EITHER SIDE. DECIDED TO MAKE SOME CHANGES IN THE ANALYSIS AT 12Z...ESSENTIALLY BREAKING THE PERSISTENT FRONT BETWEEN 65W AND 72W DUE TO EXTENSIVE SLYS BLOWING IN THAT ZONE. A WARM FRONT RESUMES AT 29N72W AND CONNECTS TO A 1016 MB LOW OVER CENTRAL FLORIDA. THIS FRONTAL SYSTEM IS PRODUCING SCATTERED TO NUMEROUS SHOWERS AND TSTMS ALONG AND OFF THE E COAST OF FLORIDA AND OVER THE NW BAHAMAS FROM 26N-30N BETWEEN 74W-80W. FARTHER E...THERE HAS BEEN LITTLE CHANGE OVER THE PAST FEW DAYS WITH RIDGING STILL DOMINATING BOTH AT THE SFC AND ALOFT. THE SFC AZORES HIGH IS ANALYZED 1032 MB NEAR 37N26W. THIS HIGH IS PRODUCING A LARGE AREA OF MODERATE TRADES ACROSS THE ATLC. STRONG NLY WINDS ARE NEAR THE AFRICAN COAST DUE TO THE TIGHTENING PRES GRADIENT BETWEEN THE HIGH AND INVERTED TROUGHING OVER THE CONTINENT. A SERIES OF UPPER HIGHS ARE PROVIDING A VERY STABLE AIRMASS ACROSS THE CENTRAL AND E ATLC WITH ONLY LOW-LEVEL STABLE STRATOCUMULUS CLOUDS SEEN ACROSS MUCH OF THE BASIN. $$ CANGIALOSI 000 AXNT20 KNHC 051730 RRA TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU JUL 05 2007 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 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ADDED TO 12Z ANALYSIS HIGHLY TITLED ALONG 4N28W 11N26W 16N21W ESTIMATED TO BE MOVG W 10-15 KT. THE DAKAR UPPER AIR TIME SECTION SHOWED A DISTINCT WAVE PASSAGE LATE JUNE 2ND/EARLY JUNE 3. THIS BROAD WAVE CONTAINS AN AREA OF LOW-LEVEL TURNING IN THE VICINITY OF 10N27W WELL DEPICTED BY A PAIR OF SURROUNDING SHIP OBS. IN ADDITION...THESE OBS ALSO INDICATE THAT THERE IS SLIGHTLY LOWER PRES NEAR THE ANALYZED AXIS AS COMPARED WITH SFC OBS TO IT'S E AND ALONG THE W AFRICAN COAST. A LARGER SCALE INVERTED V-TYPE STRUCTURE IS APPARENT FURTHER TO THE NE...WHICH WAS THE REASON FOR SLOPING THE WAVE IN THAT DIRECTION. MINIMAL SHOWER ACTIVITY IS ASSOCIATED WITH THIS FEATURE. A 1014 MB LOW PRES SYSTEM CENTERED NEAR 11N49W IS MOVING W 10-15 KT. THIS WEAK LOW CONTINUES TO HAVE MINIMAL TSTM ACTIVITY CONFINED TO THE SRN SEMICIRCLE. VIS IMAGERY TODAY HAS SHOWN THAT THE CIRCULATION APPEARS OPEN AT TIMES...SO TO BETTER FIT THE OVERALL STRUCTURE A TROPICAL WAVE WILL BE ADDED ALONG THE LOW AT 18Z. A TROPICAL WAVE IS TITLED ALONG 61W/62W MOVING W NEAR 15 KT. ASSOCIATED SCATTERED SHOWERS ARE OVER THE SRN WINDWARD ISLANDS AND OVER PORTIONS OF LEEWARD ISLANDS. HOWEVER...DEEP MOISTURE REMAINS LIMITED LIKELY CAPPED BY THE STRONGLY SUBSIDENT ENVIRONMENT THAT IT IS ENTRENCHED IN. OVERALL...THE STRUCTURE OF THE WAVE IS LESS DEFINED TODAY WITH THE PSN BASED MOSTLY A PERTURBATION IN THE ITCZ AND 24-H PRES TENDENCIES. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 7N25W 4N36W 6N50W 8N60W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 120 NM S OF THE AXIS BETWEEN 15W-22W AND WITHIN 90 NM N OF AXIS BETWEEN 30W-34W. ...DISCUSSION... GULF OF MEXICO... SHOWERS AND TSTMS CONTINUE TO AFFECT PORTIONS OF THE NW GULF...LOUISIANA AND E TEXAS. THE COMBINATION OF UPPER DIFFLUENCE...BETWEEN AN UPPER LOW OVER NRN MEXICO AND AN UPPER HIGH OVER THE N CENTRAL GULF...AND A TROUGH OF LOW PRES ARE THE CULPRITS IN PRODUCING THE ACTIVITY HERE OVER AT LEAST THE PAST FEW DAYS. IN THE E GULF...A WEAK SFC TROUGH HANGS WSW FROM A 1015 MB LOW NEAR SARASOTA FLORIDA TO 26N87W. MOST OF THE DYNAMICS PRODUCING TSTM ACTIVITY LIES OFF THE E COAST OF FLORIDA...MORE ON THIS IN THE ATLC SECTION. TIGHTENED PRES GRADIENT BETWEEN HIGH PRES OVER THE SE STATES AND LOWER PRES OVER TEX/MEX IS PRODUCING MODERATE SELY WINDS ACROSS THE SW GULF. THE UPPER FLOW IS PREDOMINATELY N-NELY CAUGHT BETWEEN AN UPPER RIDGE OVER THE EPAC AND AN UPPER LOW OVER THE NW CARIB. THIS FLOW IS ADVECTING BROKEN HIGH LEVEL CLOUDINESS ACROSS THE BULK OF THE AREA. CARIBBEAN SEA... A SURGE OF DRY AIR ALOFT CONTINUES TO PROPAGATE W ACROSS THE CARIB ADVECTED TO ABOUT 82W FROM THE TROPICAL ATLC. THIS STABLE AIRMASS IS PROVIDING FAIR WEATHER ACROSS MUCH OF THIS REGION. THE EXCEPTION IS OVER THE LESSER ANTILLES WHERE PATCHY SHOWER ACTIVITY IS AFFECTING THE SRN WINDWARDS AND NRN LEEWARDS ASSOCIATED WITH A TROPICAL WAVE IN THE VICINITY. THE UPPER ATMOSPHERE IS MORE MOIST FURTHER W SUPPORTED BY AN UPPER LOW SPINNING OVER GUATEMALA. BUT EVEN HERE...DEEP MOISTURE IS CONFINED TO THE EXTREME SW CARIB AND OVER PANAMA...COSTA RICA AND SRN NICARAGUA ENHANCED BY THE ITCZ. A SMALLER LESS DEFINED UPPER LOW HAS BEEN NEARLY STATIONARY OVER THE PAST COUPLE DAYS ABOVE THE WINDWARD PASSAGE. INSTABILITY NEAR THIS LOW PRODUCED A BRIEF BURST OF CONVECTION THIS MORNING BUT THIS HAS COMPLETELY FIZZLED WITH ONLY A FEW SHOWERS LEFTOVER. AT THE SFC...A 1058 Z QSCAT PASS SHOWED A LARGE AREA OF 20-30 KT ELY TRADES ACROSS THE REGION FROM 11N-18N...STRONGEST NEAR THE COAST OF COLOMBIA. ATLANTIC OCEAN... A STALLED FRONT CLIPS THE AREA ALONG 32N52W 30N65W WITH A WEAK LOW POSSIBLY FORMING ALONG IT'S TAIL. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 60 NM EITHER SIDE. DECIDED TO MAKE SOME CHANGES IN THE ANALYSIS AT 12Z...ESSENTIALLY BREAKING THE PERSISTENT FRONT BETWEEN 65W AND 72W DUE TO EXTENSIVE SLYS BLOWING IN THAT ZONE. A WARM FRONT RESUMES AT 29N72W AND CONNECTS TO A 1016 MB LOW OVER CENTRAL FLORIDA. THIS FRONTAL SYSTEM IS PRODUCING SCATTERED TO NUMEROUS SHOWERS AND TSTMS ALONG AND OFF THE E COAST OF FLORIDA AND OVER THE NW BAHAMAS FROM 26N-30N BETWEEN 74W-80W. FARTHER E...THERE HAS BEEN LITTLE CHANGE OVER THE PAST FEW DAYS WITH RIDGING STILL DOMINATING BOTH AT THE SFC AND ALOFT. THE SFC AZORES HIGH IS ANALYZED 1032 MB NEAR 37N26W. THIS HIGH IS PRODUCING A LARGE AREA OF MODERATE TRADES ACROSS THE ATLC. STRONG NLY WINDS ARE NEAR THE AFRICAN COAST DUE TO THE TIGHTENING PRES GRADIENT BETWEEN THE HIGH AND INVERTED TROUGHING OVER THE CONTINENT. A SERIES OF UPPER HIGHS ARE PROVIDING A VERY STABLE AIRMASS ACROSS THE CENTRAL AND E ATLC WITH ONLY LOW-LEVEL STABLE STRATOCUMULUS CLOUDS SEEN ACROSS MUCH OF THE BASIN. $$ CANGIALOSI