000 AXPZ20 KNHC 151611 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON JUL 15 2013 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1430 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 97W N OF 08N TO COAST OF MEXICO MOVING W 10 KT. THE SHARP WAVE AXIS IS CLEARLY IDENTIFIABLE IN SATELLITE IMAGERY AS WELL AS TPW ANIMATIONS...WITH SCATTERED MODERATE TO STRONG CONVECTION OCCURRING ALONG AND JUST AHEAD OF THE AXIS...N OF 10N BETWEEN 97W AND 100W. A NARROW AND ELONGATED TROUGH PREVAILS JUST A FEW DEGREES TO THE W AND NW OF THIS WAVE AND IS PRODUCING A DRY AND STABLE ATMOSPHERE AHEAD OF THE WAVE. HOWEVER...THIS TROUGH IS SHIFTING SLOWLY WWD AND ALMOST IN TANDEM WITH THE WAVE. THUS CONVECTION OCCURRING AHEAD OF THE WAVE WILL LIKELY CONTINUE DURING THE NEXT 24 HOURS. GLOBAL MODELS SUGGEST THE WAVE WILL CONTINUE TO PROPAGATE WWD AND GRADUALLY CATCH UP TO AND MERGE WITH THE ELONGATED UPPER TROUGH TO ITS W WITHIN 48 HOURS. THIS WILL LEAD TO A WEAKENING TREND IN CONVECTION AND A WEAKENING OF THE WAVE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 08.5N75W TO 09N84W THEN MEANDERS WWD THROUGH 10N98W TO 11.5N112W TO LOW PRES NEAR 11.5N125W 1008 MB TO 09.5N133W...WHERE IT TRANSITIONS TO ITCZ... CONTINUING ON TO 09N137W TO BEYOND 08N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED FROM 04.5N TO 09N E OF 90W. ISOLATED TO SCATTERED STRONG WITHIN 150 NM S OF THE TROUGH BETWEEN 95W AND 104W. SCATTERED MODERATE CONVECTION NOTED WITHIN 120 NM N OF ITCZ W OF 133W. ...DISCUSSION... A VERY COMPLEX UPPER LEVEL BLOCKING PATTERN CONTINUES TO DOMINATE THE SUB TROPICS AND MID LATITUDES OF THE HEMISPHERE TODAY...SPANNING THE BROAD REGION BETWEEN 50W AND 165W. ACROSS THE DISCUSSION AREA...GENERALLY FAIR AND STABLE CONDITIONS PREVAIL ACROSS MUCH OF THE AREA...WITH SIGNIFICANT MOISTURE AND WEATHER CONFINED TO A NARROW REGION BETWEEN 06N AND 14N. AN UPPER ANTICYCLONE IS EVIDENT AT 16N134W WITH RIDGE EXTENDING N TO 29N-30N AND NEWD TO 28N125W. A WEAKENING SHORTWAVE TROUGH IS JUST W OF THE RIDGE AREA FROM 21N147W TO 11N143W...AND IS BEING SQUEEZED FROM BOTH THE E AND W BY EXPANDING RIDGES. E OF THE AFOREMENTIONED RIDGE IS A CUT OFF MIDDLE TO UPPER CYCLONE CENTERED NEAR 20N118W DRIFTING VERY SLOWLY WWD. THE ASSOCIATED CYCLONIC CIRCULATION EXTENDS N TO 27N AND IS COMBINING WITH A RIDGE CENTERED ACROSS THE SW U.S. TO PRODUCE DEEP SE MIDDLE TO UPPER LEVEL FLOW ACROSS MUCH OF THE W COAST OF MEXICO...FROM NEAR MANZANILLO N AND NWWD ACROSS BAJA CALIFORNIA AND INTO THE ADJACENT PACIFIC. THIS FLOW IS ADVECTING ABUNDANT MIDDLE LEVEL MOISTURE AND IS ACTING TO DESTABILIZE THE ATMOSPHERE ACROSS THE THE SIERRA MADRE OCCIDENTALES...THE GULF OF CALIFORNIA...AND BAJA CALIFORNIA. A NARROW UPPER RIDGE LIES TO THE S OF THIS CYCLONIC FLOW...EXTENDING FROM AN UPPER ANTICYCLONE OVER THE GULF OF HONDURAS WWD TO A SECOND UPPER ANTICYCLONE NEAR 13N112W. THESE TWO HIGHS ARE SEPARATED BY A NARROW TROUGH AXIS ALONG 102W MENTIONED ABOVE WITH THE TROPICAL WAVE. BROAD AND ELONGATED CYCLONIC FLOW PREVAILS S OF THIS NARROW RIDGE...CENTERED NEARLY ALONG THE EQUATOR...FROM THE COAST OF ECUADOR TO ABOUT 140W. AT LOW LEVELS...A RIDGE EXTENDS FROM A STRONG 1038 MB HIGH N OF THE DISCUSSION AREA AT 47N145W S AND SEWD INTO THE DISCUSSION AREA TO NEAR 20N116W. A MODEST PRES GRADIENT PERSISTS TO THE S BETWEEN THE HIGH AND THE ITCZ...AND IS YIELDING NE TRADES AT SPEEDS OF 15-20 KT GENERALLY S OF 18-20N AND W OF 120W. SEAS THERE AREA RUNNING 5-7 FT... AND ARE FORECAST TO CHANGE LITTLE OVER THE NEXT 48 HRS. THE LOW PRES CENTER ALONG THE W END OF THE MONSOON TROUGH AT 11.5N125W HAS ENTERED INTO AN UPPER LEVEL DEFORMATION ZONE...WHICH HAS GREATLY ENHANCED CONVECTION TO THE W OF THE LOW. SCATTERED DEEP CONVECTION WILL LIKELY CONTINUE W OF THE LOW FOR THE NEXT 24 HOURS. THE PRES GRADIENT S OF THE RIDGE IS FORECAST TO STRENGTHEN OVER THE NEXT FEW DAYS AS THIS LOW MOVES SLOWLY W...AND WILL INCREASE WINDS TO AROUND 20 KT N AND NW OF THE LOW. TO THE SE OF THE RIDGE...WINDS ARE LIGHT TO MODERATE OFF THE WEST COAST OF THE BAJA CALIFORNIA PENINSULA...AND ARE EXPECTED TO PERSIST THROUGH EARLY TUE...THEN INCREASE TO NW AT 15 KT ON TUE NIGHT ACROSS THESE WATERS TO THE N OF 28N. NW WINDS OF 15-20 KT ARE EXPECTED N OF 25N W OF THE BAJA PENINSULA TO ALONG 122W ON THU...WITH ASSOCIATED SEAS TO 7 FT. ACROSS THE TROPICS E OF 110W...FRESH TRADE WINDS ACROSS THE CARIBBEAN ARE RESULTING IN MODEST PULSING OF NOCTURNAL GAP WINDS THROUGH THE GULF OF PAPAGAYO...WITH NIGHT TIME NE TO E WINDS EXPECTED TO PEAK AT 15-20 KT EACH OF THE NEXT FEW NIGHTS. SW SOUTHERN HEMI SWELL OF SMALL TO MODERATE SIZE CONTINUES TO DOMINATE MARINE CONDITIONS S OF 20N...AND WILL CONTINUE TO DO SO FOR THE NEXT SEVERAL DAYS. A STRONG AND LARGE SW SWELL IS CURRENTLY MOVING THROUGH FRENCH POLYNESIA IN THE S CENTRAL PACIFIC AND HAS BEGUN TO CROSS THE EQUATOR AND ENTER THE LOCAL WATERS THIS MORNING...AND WILL INCREASE SEAS TO 8 FT OR GREATER WITHIN A FEW DEGREES OF THE EQUATOR TUE THROUGH THU. THIS STRONG SW SWELL EVENT WILL HIT THE PACIFIC COASTS OF CENTRAL AMERICA...MEXICO... AND SOUTHERN CALIFORNIA BY MID WEEK AND GENERATE VERY STRONG AND POWERFUL SURF ALONG THE COASTS. $$ STRIPLING