000 AXPZ20 KNHC 220921 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC MON JUN 22 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 MOVING ACROSS CENTRAL AMERICA EXTENDS FROM 16N85W INTO THE EPAC TO NEAR 07N85W. CONVECTION HAS DIMINISHED IN ASSOCIATION WITH THIS WAVE OVER THE PAST FEW HOURS AND NOW ONLY FEW SHOWERS ARE NOTED NEAR THE SOUTHERN END OF THE WAVE AXIS. SSMI TPW IMAGERY INDICATES A MODEST SURGE OF MOISTENED AIR IN ASSOCIATION WITH THIS SYSTEM AND MAINLY S OF 13N. A TROPICAL WAVE IS ALONG 97W/98W FROM 06N-15N MOVING W AT 10-15 KT. ISOLATED TO SCATTERED MODERATE CONVECTION IS NOTED NEAR THE INTERSECTION OF THE WAVE WITH THE ITCZ AXIS. A TROPICAL WAVE IS ALONG 113W/114W FROM 07N-15N MOVING W AT 15 KT. INSTABILITY BEING PROVIDED BY AN UPPER LEVEL LOW IN THE VICINITY OF THE WAVE IS RESULTING IN SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 75-90 NM ON EITHER SIDE OF THE WAVE AXIS. AN ACTIVE TROPICAL WAVE IS ALONG 134W/135W FROM 06N-13N MOVING W ABOUT 15 KT. THIS WAVE IS UNDER BROAD ANTICYCLONIC FLOW ALOFT AND IS EMBEDDED IN A VERY DEEP MOIST LOW-LEVEL ATMOSPHERIC ENVIRONMENT AS OBSERVED ON THE SSMI TPW SATELLITE ANIMATION. THE WAVE IS ENHANCING CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION MAINLY WITHIN AROUND 180 NM E OF AXIS BETWEEN 10N-12N AND FROM 06N-11N BETWEEN THE WAVE AXIS AND 139W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 07N78W TO 06N85W WHERE THE ITCZ BEGINS AND CONTINUES TO 08N97W TO 09N112W TO 07N125W TO 09N133W TO 08N140W. OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 04N TO 08N BETWEEN 120W AND 131W. ...DISCUSSION... UPPER LEVELS...AN ANTICYCLONE LOCATED NEAR 07N138W EXTENDS A RIDGE NORTHWARD TO NEAR 20N132W AND DOMINATES MOST OF THE FORECAST AREA S OF 20N W OF 118W. UPPER DIFFLUENCE ASSOCIATED WITH THIS SYSTEM IS HELPING TO SUSTAIN THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE LOCATED ALONG 134W/135W. AN UPPER-LEVEL TROUGH IS ACROSS THE NORTHERN PERIPHERY OF THE RIDGE AND STRETCHES FROM AN UPPER-LOW LOCATED W OF AREA NEAR 20N144W TO 23N130W TO NEAR 20N124W. ANOTHER ANTICYCLONE IS NEAR THE ARIZONA/NEW MEXICO BORDER AND DOMINATES NW MEXICO AND NORTHERN BAJA CALIFORNIA. AN UPPER-LEVEL TROUGH EXTENDS FROM EASTERN TEXAS SW TO N CENTRAL MEXICO...AND CONTINUES W FROM THERE AS A SHEAR AXIS TO A SMALL UPPER LEVEL LOW LOCATED NEAR 25N116W. 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 20N104W...AND A BROAD UPPER LOW NOW CENTERED OVER THE YUCATAN PENINSULA. BROAD RIDGING COVERS THE FAR EASTERN PACIFIC E OF ABOUT 87W...INCLUDING COSTA RICA AND PANAMA. A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH THIS RIDGE SUPPORTS THE CONVECTIVE ACTIVITY RELATED TO A TROPICAL WAVE WITH AXIS ALONG 85W. THE RIDGING IS ALSO AIDING A FEW CLUSTERS OF SCATTERED MODERATE CONVECTION OVER PARTS OF NORTHERN COLOMBIA. AT THE SURFACE...A 1021 MB HIGH PRES LOCATED NEAR 32N133W EXTENDS A RIDGE SE ACROSS THE N WATERS TO NEAR 20N110W. 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 132W AS HIGHLIGHTED BY RECENT SCATTEROMETER PASSES. SEAS WITHIN THIS AREA OF TRADES ARE IN THE RANGE OF 6-8 FT IN MIXED SWELLS. NWP MODELS SUGGEST THAT A WEAK HIGH PRES WILL REMAIN OVER THE FAR NW PART OF THE AREA DURING THE NEXT 48 HOURS WHILE A SURFACE TROUGH IS FORECAST TO PERSIST OVER NORTHERN BAJA CALIFORNIA AND THE NE WATERS. THE PRES GRADIENT WILL SLIGHTLY INCREASE OVER THE FAR NE WATERS BY WED BETWEEN THE ABOVE MENTIONED HIGH PRES AND LOWER PRES OVER THE SW CONUS AND THE NORTHERN GULF OF CALIFORNIA. A COLD FRONT APPROACHING FROM THE WEST WILL BECOME STATIONARY JUST WEST OF AREA LATER TODAY AND DISSIPATE ON TUE. LONG PERIOD CROSS-EQUATORIAL MIXED SE AND SW SWELLS ARE PRODUCING SEAS TO 8 FT OVER THE SW WATERS S OF LINE FROM 03N140W TO 06N133W TO 00N125W. THIS AREA OF SWELLS WILL GRADUALLY DIMINISH OVER THE NEXT 24 HOURS WITH SEAS TO 8 FT LINGERING MAINLY S OF THE EQUATOR W OF 120W. GAP WINDS... GULF OF PAPAGAYO...A RECENT ASCAT PASS CONFIRMED THE PRESENCE OF FRESH TO STRONG NE-E WINDS ACROSS THE GULF OF PAPAGAYO AND DOWNWIND FROM 09N-12N E OF 89W. PULSING WINDS OF 20-25 KT ARE EXPECTED TO PERSIST 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 AROUND 10 FT TODAY. THE RESULTANT ENE SWELLS WILL PROPAGATE WESTWARD REACHING TO NEAR 98W BY LATE MON NIGHT. GULF OF TEHUANTEPEC...N WINDS OF 20-25 KT WILL COMMENCE THROUGH THE GULF BEGINNING EARLY THIS MORNING. THESE WINDS ARE FORECAST TO DIMINISH TO 15-20 KT BY EARLY THIS AFTERNOON...BUT WILL PULSE AGAIN TO 20-25 KT LATE MON NIGHT INTO TUE MORNING. WINDS WILL FURTHER INCREASE TO 25-30 KT LATE TUE NIGHT INTO WED MORNING WITH SEAS BUILDING TO 9-10 FT. THE COMBINATION OF A TROUGH OVER THE SW GULF OF MEXICO AND THE PASSAGE OF A TROPICAL WAVE WILL HELP TO MAINTAIN THIS GAP WIND EVENT. $$ GR