000 AXPZ20 KNHC 210242 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN JUL 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0215 UTC. ...TROPICAL WAVES... THE WEAK TROPICAL WAVE PREVIOUSLY LOCATED ALONG 19N114W TO 13N118W HAS WEAKENED. A SURFACE TROUGH IS ANALYZED ON THE 0000 UTC MAP EXTENDING FROM 19N111W TO 13N115W. ONLY A FEW SHOWERS ARE NOTED NEAR THE TROUGH AXIS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 11N85W TO A 1010 MB LOW PRES LOCATED NEAR 11N102W TO 09N108W TO 12N116W TO 12N125W. ITCZ AXIS CONTINUES FROM 12N125W TO BEYOND 11N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 05N TO 07N BETWEEN 84W AND 91W...AND FROM 07N TO 09N BETWEEN 92W AND 96W. SCATTERED MODERATE CONVECTION IS FROM 06N TO 08N BETWEEN 100W AND 105W... AND FROM 10N TO 13N BETWEEN 99W AND 106W. ...DISCUSSION... ALOFT...UPPER LEVEL CYCLONIC CIRCULATION LOCATED OVER BAJA PENINSULA NEAR 28N113W CONTINUES TO TRIGGER SCATTERED SHOWERS AND ISOLATED TSTMS MAINLY FROM 27N TO 29N. ABUNDANT DEEP LEVEL TROPICAL MOISTURE COVERS MOST OF MEXICO AND ACROSS CENTRAL AMERICA. AN ANTICYCLONE CENTERED NEAR 15N136W DOMINATES THE WEST- CENTRAL WATERS AND EXTENDS A RIDGE NORTHWARD TO BEYOND 30N131W. TO THE EAST OF THE RIDGE...AN UPPER LEVEL TROUGH STRETCHES FROM 30N128W TO 20N128W TO 16N130W. MODERATE TO STRONG SUBSIDENCE AND IMPLIED DRY AIR MASS IS NOTED ACROSS MUCH OF THE AREA N OF 16N W OF 125W. ANOTHER ANTICYCLONE SITUATED ALONG THE COAST OF MEXICO NEAR 23N106W EXTENDS A RIDGE S COVERING MAINLY THE AREA N OF 20N BETWEEN 98W AND 110W. UPPER DIFFLUENCE ASSOCIATED WITH THIS FEATURE COUPLE WITH A TROPICAL WAVE INLAND ALONG 98W IS HELPING TO INDUCE CONVECTION OVER CENTRAL MEXICO...ESPECIALLY W OF THE WAVE AXIS. EASTERLY WINDS ALOFT COVERS MOST OF THE AREA N OF 05N E OF 110W. THESE WINDS ARE TRANSPORTING DEBRIS CLOUDINESS FROM CONVECTION ALONG AND NEAR THE MONSOON TROUGH. SURFACE RIDGE ASSOCIATED WITH A SUBTROPICAL HIGH N OF THE AREA EXTENDS N OF 16N W OF 120W. TRADE WINDS OF 15-20 KT S OF THE RIDGE ARE PRODUCING AN AREA OF 7-8 FT SEAS W OF 135W. GALE FORCE N WINDS ALONG THE COAST OF NORTHERN CALIFORNIA WILL INCREASE SEAS TO 8-9 FT N OF 28N BETWEEN 124W AND 132W THROUGH AT LEAST MON. A WEAK SURFACE LOW IS DEVELOPING ALONG THE MONSOON TROUGH NEAR 11N102W. SOME BANDING-LIKE FEATURES ARE NOTED PARTICULARLY IN THE SOUTHWESTERLY WIND FLOW. EARLIER SCATTEROMETER DATA SHOWED S TO SW WINDS TO 20 KT SE OF THE LOW CENTER. MARINE GUIDANCE INDICATES AN AREA OF 8 FT SEAS ASSOCIATED WITH THIS SLY WIND FLOW MOVING IN TANDEM WITH THE WEAK LOW PRES OVER THE NEXT 24-48 HOURS. EXPECT INCREASING WINDS TO 20-25 KT AND SEAS TO 8 FT ACROSS THE GULF OF PAPAGAYO SUN NIGHT INTO MON MORNING AS FRESH TO STRONG WIND FLOW IN THE SW CARIBBEAN FUNNELS THROUGH THE GAP. $$ GR