000 AXPZ20 KNHC 210917 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN JUN 21 2015 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...TROPICAL WAVES... A TROPICAL WAVE AXIS IS ALONG 93W N OF 07N MOVING W AT 10-15 KT. ONLY ISOLATED MODERATE CONVECTION IS NEAR THE SOUTHERN END OF THE WAVE AXIS. A TROPICAL WAVE AXIS IS ALONG 108W FROM 07N-15N MOVING W NEAR 15 KT. ISOLATED MODERATE CONVECTION IS NEAR THE WAVE AXIS. A RECENT SCATTEROMETER PASS CLEARLY DEPICTED THE WIND SHIFT ASSOCIATED WITH THE WAVE AXIS. A TROPICAL WAVE AXIS IS ALONG 128W FROM 05N-13N MOVING W NEAR 15 KT. SCATTERED MODERATE CONVECTION IS NOTED WHERE THE WAVE MEETS THE ITCZ NEAR 08N128W. SCATTERED SHOWERS ARE ELSEWHERE NEAR THE WAVE AXIS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 07N78W TO 08N84W TO 04N99W. THE ITCZ BEGINS AT 04N99W...AND CONTINUES FROM 06N110W TO 08N127W THEN RESUMES W OF A TROPICAL WAVE AT 08N130W TO 07N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 03N TO 06N BETWEEN 87W AND 90W. SIMILAR CONVECTION IS FROM 10N TO 12N BETWEEN 102W AND 104W...AND S OF THE ITCZ AXIS W OF 130W. ...DISCUSSION... UPPER LEVELS...THE FLOW PATTERN ASSOCIATED WITH AN ANTICYCLONE GRADUALLY LIFTING NEWD NEAR 28N125W...AND ANOTHER ONE OVER FAR NORTHERN BAJA CALIFORNIA CONTINUES TO DOMINATE THE NORTHERN PART OF THE AREA MAINLY N OF 20N W OF 110W. ANOTHER ANTICYCLONE IS FARTHER S NEAR 13N123W. AN UPPER-LEVEL TROUGH EXTENDS ACROSS NW MEXICO AND SOUTHERN BAJA CALIFORNIA TO AN UPPER-LEVEL LOW LOCATED NEAR 23N114W. A TROUGH EXTENDS FROM THIS LOW TO NEAR 18N112W. THEN...AN INVERTED TROUGH CONTINUES ALONG 111W FROM 06N TO 16N. WATER VAPOR SATELLITE IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE WITH RESULTANT DRY AIR COVERING MUCH OF THE FORECAST AREA N OF 15N W OF 110W. NORTHERLY FLOW PERSISTS OVER SOUTHEASTERN MEXICO...THE GULF OF TEHUANTEPEC AND THE REMAINDER OF THE AREA N OF 10N BETWEEN 91W-100W DUE TO THE COMBINATION OF AN ANTICYCLONE OVER MEXICO NEAR 21N101W...AND A BROAD UPPER LOW CENTERED OVER THE NW YUCATAN PENINSULA. BROAD RIDGING COVERS THE FAR EASTERN PACIFIC E OF ABOUT 87W...INCLUDING COSTA RICA AND PANAMA. UPPER DIFFLUENCE ASSOCIATED WITH THIS RIDGE IS HELPING TO SUSTAIN A CLUSTER OF MODERATE TO STRONG CONVECTION OVER COSTA RICA AND REGIONAL WATERS. THIS CONVECTIVE ACTIVITY ALSO COVERS THE AREA FROM 06N TO 10N BETWEEN 84W AND 88W. AT THE SURFACE...A RIDGE COVERS THE N WATERS MAINLY N OF 18N W OF 120W WHILE A WEAK TROUGH HAS DEVELOPED OVER THE NE PART OF THE AREA AND EXTENDS FROM 26N115W TO 22N123W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES IN THE VICINITY OF THE ITCZ IS MAINTAINING MODERATE TO LOCALLY FRESH NE-E TRADES OVER THE WESTERN PART OF THE FORECAST REGION N OF THE ITCZ FROM 10N-16N W OF 128W AS HIGHLIGHTED BY SCATTEROMETER DATA. SEAS ARE IN THE RANGE OF 6-8 FT PRIMARILY IN MIXED NE AND SE SWELLS WITHIN THIS AREA OF TRADES. BASED ON GLOBAL MODELS...A WEAK HIGH PRES WILL REMAIN OVER THE FAR NW PART OF THE AREA DURING THE NEXT 48-72 HOURS WHILE A SURFACE TROUGH IS FORECAST TO PERSIST OVER NORTHERN BAJA CALIFORNIA AND THE NE WATERS. A RECENT ASCAT PASS PROVIDED OBSERVATIONS OF MAINLY FRESH SOUTHERLY WINDS ACROSS THE GULF OF CALIFORNIA...PARTICULARLY BETWEEN 26N AND 29W. THESE WINDS COULD BE ASSOCIATED WITH THE DEVELOPED STRONG CONVECTION OVER THE SIERRA MADRE MOUNTAINS. MARINE GUIDANCE SUGGESTS MAINLY MODERATE TO LOCALLY FRESH WINDS ACROSS THIS AREA OVER THE NEXT 24-48 HOURS. LONG PERIOD CROSS EQUATORIAL SW SWELL DOMINATES MOST OF THE FORECAST WATERS E OF 110W WHILE SE SWELL CONTINUES TO PROPAGATE ACROSS MUCH OF THE WATERS W OF 110W. THE SE SWELL IS PRODUCING AN AREA OF SEAS TO 9 FT S OF 04N W OF 123W. THESE SEAS ARE FORECAST TO SUBSIDE TO LESS THAN 8 FT IN ABOUT 48 HOURS. GAP WINDS... GULF OF PAPAGAYO...PULSING WINDS OF 20-25 KT ARE EXPECTED ACROSS THIS GULF DURING THE LATE NIGHT AND EARLY MORNING HOURS WITH THE ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW AND SOME ADDED ENHANCEMENT FROM THE EASTERLY GRADIENT FLOW ACROSS THE SW CARIBBEAN. SEAS ARE FORECAST TO BUILD UP TO 10 FT EARLY THIS AFTERNOON. THE RESULTANT ENE SWELLS WILL PROPAGATE WESTWARD REACHING TO NEAR 100W BY LATE MON. THESE WINDS WILL PULSE AGAIN TO 20-25 KT LATE TONIGHT INTO EARLY MON MORNING. GULF OF TEHUANTEPEC...EXPECT ALSO PULSING WINDS OF 20-25 KT ACROSS THIS GULF LATE TONIGHT INTO EARLY MON MORNING AS A TROPICAL WAVE APPROACHES FROM THE EAST AND PASSES THROUGH THE ISTHMUS OF TEHUANTEPEC. BY EARLY MON AFTERNOON...THESE WINDS ARE FORECAST TO DIMINISH TO 15-20 KT...BUT WILL PULSE AGAIN TO 20-25 KT LATE MON NIGHT INTO TUE MORNING. SEAS ARE FORECAST TO BUILD TO AROUND 8 FT WITH THIS PULSING WINDS. GULF OF PANAMA...MODERATE TO LOCALLY FRESH NORTHERLY WINDS ARE EXPECTED ACROSS THIS GULF OVER THE NEXT COUPLE OF DAYS WITH SEAS GENERALLY UNDER 5 FT. $$ GR