000 AXPZ20 KNHC 212205 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...TROPICAL WAVES... A TROPICAL WAVE HAS ENTERED THE FAR EASTERN PORTION WITH ITS AXIS ALONG 83W N OF 08N TO ACROSS EASTERN COSTA RICA AND OVER THE FAR SW CARIBBEAN SEA JUST E OF THE COAST OF NICARAGUA MOVING W ABOUT 10 KT. SCATTERED STRONG CONVECTION IS FIRING UP ACROSS MUCH OF COSTA RICA AND WESTERN PANAMA. OTHERWISE...ONLY ISOLATED MODERATE CONVECTION IS NOTED WITHIN 180 NM W AND 60 NM E OF THE WAVE AXIS. A TROPICAL WAVE AXIS IS ALONG 95W FROM 06N-15N MOVING W AT 10-15 KT. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF 10.5N95.5W. A TROPICAL WAVE AXIS IS ALONG 112W/113W FROM 08N-15N MOVING W 15 KT. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF 13.5N112W. INSTABILITY BEING PROVIDED AN UPPER LEVEL LOW CENTERED JUST TO THE SE OF THE WAVE IS RESULTING IN SCATTERED SHOWERS AND ISOLATED TSTMS ELSEWHERE WITHIN 180 NM OF THE WAVE AXIS. A TROPICAL WAVE AXIS IS ALONG 132W/133W FROM 05N-13N MOVING W ABOUT 15 KT. THIS WAVE IS UNDER BROAD ANTICYCLONIC FLOW ALOFT ...AND IS EMBEDDED 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 S OF THE ITCZ AS DESCRIBED BELOW. SCATTERED SMALL CLUSTERS OF MODERATE CONVECTION ARE SEEN WITHIN 30 NM OF 11N132W...AND WITHIN 30 NM OF 10N131.5W. THE UPPER ANTICYCLONIC FLOW SHOULD SUPPORT THE CURRENT ONGOING CONVECTION THROUGH THE NEXT 24-48 HOURS AS THE WAVE CONTINUES WESTWARD TO JUST W OF 140W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... SCATTEROMETER DATA INDICATES THAT A WEAK MONSOON TROUGH EXTENDS W OFF THE COAST OF COLOMBIA FROM 07N78W TO 07N87W...THEN TURNS SW TO 06N95W WHERE THE ITCZ FORMS AND THEN CONTINUES W TO 06N104W AND NW TO 07N112 WHERE IT TEMPORARILY ENDS. IT RESUMES AGAIN AT 07N116W TO 08N130W TO 08N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 06N-09N BETWEEN 93W-97W...FROM 10N-13N BETWEEN 102W-107W...AND FROM 01N-09N W OF 131W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE TROUGH BETWEEN 78W-82W. ...DISCUSSION... UPPER LEVELS...THE FLOW PATTERN ASSOCIATED WITH AN ANTICYCLONE OVER THE EASTERN ARIZONA CONTINUES TO DOMINATE THE NORTHERN PART OF THE AREA MAINLY N OF 20N W OF 110W. ANOTHER ANTICYCLONE IS FARTHER S NEAR 13N123W. A SHARP 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 25N115W. A TROUGH EXTENDS FROM THIS LOW TO NEAR 18N112W...THEN BECOMES A SHEAR AXIS TO AN ELONGATED UPPER LOW AT 08N111W. 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 AND ALSO THE FAR SW PORTION WHERE AN ANTICYCLONE IS SITUATED AT 05N135W. UPPER DIFFLUENCE ASSOCIATED WITH THIS RIDGE IS HELPING TO SUSTAIN CLUSTERS OF STRONG CONVECTION DEVELOPING ACROSS MUCH OF COSTA RICA AND WESTERN PANAMA. THIS ACTIVITY IS TIED TO THE TROPICAL WAVE ALONG 83W AS DESCRIBED ABOVE. THE RIDGING IS ALSO AIDING THE SCATTERED MODERATE CONVECTION S OF THE MONSOON TROUGH BETWEEN 78W-82W. AT THE SURFACE...A NEARLY STATIONARY 1022 MB HIGH IS ANALYZED AT 31N131W WITH A RIDGE SE TO 21N120W. HIGH PRES COVERS THE AREA N OF 18N W OF 120W WHILE A WEAK TROUGH EXTENDS FROM 23N117W TO 21N122W. 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-17N W OF 133W 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. NWP MODELS SUGGEST THAT 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. 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 11 FT LATE TONIGHT...AND LOWER SLIGHTLY TO 10 FT LATE MON NIGHT. THE RESULTANT ENE SWELLS WILL PROPAGATE WESTWARD REACHING TO NEAR 106 BY LATE MON NIGHT AND TO NEAR 107W EARLY ON TUE. GULF OF TEHUANTEPEC...N WINDS OF 20-25 KT WILL COMMENCE THROUGH THE GULF BEGINNING EARLY ON MON AS A TROPICAL WAVE MOVES PAST THE FAR EASTERN PART OF THE REGION AND THE ISTHMUS OF TEHUANTEPEC. THESE WINDS ARE FORECAST TO DIMINISH TO 15-20 KT BY EARLY MON AFTERNOON...BUT WILL PULSE AGAIN TO 20-25 KT LATE MON NIGHT INTO TUE MORNING. SEAS ARE FORECAST TO BUILD TO AROUND 8 FT BY LATE MON NIGHT AND TO 10 FT BY EARLY ON TUE WITH THESE NLY WINDS. $$ AGUIRRE