000 AXPZ20 KNHC 190236 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI JUL 19 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... A TROPICAL WAVE EXTENDS FROM 18N110W TO 12N112W MOVING W TO ABOUT 10 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED WITHIN 150 NM AHEAD OF THE WAVE AXIS FROM 14N TO 18N. ISOLATED MODERATE CONVECTION IS NEAR THE SOUTHERN END OF THE WAVE. AN EARLIER ASCAT PASS SHOWED THE WIND SHIFT ASSOCIATED WITH THIS FEATURE. AN INVERTED-V LOW LEVEL SIGNATURE IS STILL NOTED ON LATEST VISIBLE SATELLITE IMAGERY WITH WEAK CYCLONIC TURNING NEAR 14N. THE WAVE COINCIDES WITH A BULGE OF MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. GLOBAL MODELS SUGGEST THAT THE WAVE WILL GRADUALLY LOSE ITS SURFACE IDENTITY AS IT TRACKS WESTWARD THROUGH THE NEXT COUPLE OF DAYS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 08N100W TO 15N112W TO 10N128W. ITCZ AXIS CONTINUES FROM 10N128W TO 11N139W. SCATTERED MODERATE TO STRONG CONVECTION IS N OF 07N E OF 84W...INCLUDING PARTS OF PANAMA AND COSTA RICA. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 10N TO 16N BETWEEN 115W AND 125W. SCATTERED MODERATE CONVECTION CAN BE FOUND FROM 07N TO 11N BETWEEN 125W AND 130W...AND FROM 07N TO 10N W OF 135W. ...DISCUSSION... ALOFT...AN ANTICYCLONE LOCATED WEST OF AREA EXTENDS A RIDGE E-NE ACROSS THE WEST-CENTRAL WATERS TO NEAR 15N130W. THE WEAK UPPER LOW LOCATED NEAR 24N125W CONTINUES TO WEAKEN LEAVING A TROUGH ACROSS THE AREA THAT CURRENTLY EXTENDS FROM 30N126W TO 24N125W TO 15N128W. THE UPPER LOW IS BECOMING DIFFUSE IN THE UPPER SW FLOW AHEAD OF A BROAD UPPER TROUGH LOCATED NW OF THE DISCUSSION AREA. SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE INDUCING A DRY AND VERY STABLE ATMOSPHERIC ENVIRONMENT W OF A LINE FROM 30N124W TO 20N126W TO 15N130W TO 18N140W. AN UPPER LEVEL RIDGE IS PRESENT OVER MUCH OF THE WESTERN U.S. AND STRETCHES SSW TO THE EASTERN PORTION OF THE FORECAST REGION N OF 18N AND E OF 120W...AND ALSO SEWD TO SE MEXICO. A WELL DEFINED DEEP LAYER LOW HAS MOVED FROM NEW MEXICO INTO NORTHERN MEXICO AND IS GENERATING SOME SHOWER AND TSTM ACTIVITY THERE. ANOTHER MID TO UPPER LEVEL LOW IS SPINNING NEAR LOS MOCHIS SINALOA. ELY WINDS ALOFT DOMINATE MUCH OF THE AREA N OF 05N AND E OF ABOUT 120W. THESE WINDS ARE TRANSPORTING DEBRIS CLOUDINESS FROM CONVECTION ALONG AND NEAR THE TROPICAL WAVE AND THE MONSOON TROUGH MAINLY E OF 100W AND BETWEEN 110W AND 120W. DIFFLUENCE COUPLE WITH A TROPICAL WAVE OVER THE SW CARIBBEAN IS GENERATING THE CONVECTION OVER PARTS OF PANAMA...COSTA RICA AND REGIONAL WATERS. AT THE SURFACE...A RIDGE DOMINATES THE FORECAST WATERS N OF 15N W OF 114W. PRES GRADIENT BETWEEN THIS RIDGE AND LOWER PRES OVER WESTERN MEXICO IS RESULTING IN AREA OF NW WINDS TO 20 KT AND SEAS TO 8 FT JUST W OF BAJA CALIFORNIA TO ABOUT 120W AND N OF 26N. THESE MARINE CONDITIONS ARE FORECAST TO PERSIST TONIGHT AND WILL GRADUALLY DIMINISH ON FRI. A SURFACE TROUGH CONTINUES TO MOVE WWD ACROSS THE WEST-CENTRAL WATERS AND NOW EXTENDS FROM 15N139W TO 10N141W. NE WINDS OF 20- 25 KT AND SEAS TO 9 FT ARE NOTED BETWEEN THE TROUGH AND THE RIDGE TO THE NORTH...PARTICULARLY FROM 14N TO 18N W OF 133W. AN ALTIMETER PASS CONFIRMED THE PRESENCE OF THE 9 FT SEAS. WINDS AND SEAS ARE FORECAST TO DIMINISH LATER TONIGHT INTO FRI AS THE TROUGH MOVES WEST OF AREA. IN ABOUT 24 HOURS...EXPECT WINDS OF 20 KT OR LESS AND SEAS UNDER A 8 FT ACROSS THE ENTIRE FORECAST REGION. IN ABOUT 48 HOURS... INCREASING PRES GRADIENT BETWEEN THE COAST OF NORTHERN CALIFORNIA AND 130W WILL INCREASE WINDS TO 20-30 KT THERE. SEAS ASSOCIATED WITH THESE WINDS ARE EXPECTED TO PROPAGATE SOUTH AS NORTHERLY SWELLS REACHING THE FAR NORTH MAINLY N OF 29N BETWEEN 124W AND 130W WATERS SAT EVENING. A SURGE OF TRADE WINDS OVER THE CARIBBEAN SEA WILL PUSH GAP WINDS TO 20 KT THROUGH THE GULF PAPAGAYO AGAIN FRI MORNING. LONG PERIOD CROSS EQUATORIAL SOUTHWESTERLY SWELLS RESULTING IN COMBINED SEAS TO 8 FT DOMINATE THE FORECAST WATERS S OF LINE FROM 00N105W TO 05N114W TO 05N120W TO 00N127W. A SET OF LONG PERIOD SW SWELLS...WAVE PERIOD OF 18 TO 19 SECONDS...CONTINUES TO IMPACT MOST OF THE COASTS OF MEXICO AND CENTRAL AMERICA PRODUCING ROUGH SURF CONDITIONS AND DANGEROUS RIP CURRENTS TO THOSE COASTS. $$ GR