000 AXPZ20 KNHC 060316 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON JUL 06 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 03005 UTC. ...SPECIAL FEATURE... LOW PRES OF 1007 MB IS CENTERED NEAR 16N110W...OR ABOUT 425 MILES S OF THE SRN TIP OF BAJA CALIFORNIA. THE LOW HAS ONLY SHOWN SLIGHT ORGANIZATION IN ITS OVERALL CLOUD PATTERN SINCE THIS MORNING. LAST VISIBLE SATELLITE IMAGERY SHOWED A BAND REMOVED FROM THE CENTER CONSISTING OF SCATTERED MODERATE TO STRONG CONVECTION WITHIN 45 NM EITHER SIDE OF A LINE FROM 14N108W TO 17N107W TO 19N107W. SCATTERED MODERATE/ISOLATED STRONG IS FROM 12N TO 14N BETWEEN 108W-111W...AND WITHIN 30 NM OF 15N115W. SCATTEROMETER DATA FROM SUN DEPICTED THE A LARGE SWATH OF 20-30 KT WINDS WITHIN ABOUT 300 NM OF THE LOW IN THE NE QUADRANT. THE LOW IS FORECAST TO POSSIBLY BECOME A TROPICAL DEPRESSION OVERNIGHT OR MON AS IT MOVES WNW ABOUT 12 KT. IT IS FORECAST TO REACH NEAR 18N115W BY MON EVENING...AND TO NEAR 19N119W BY TUE EVENING. WILL KEEP MENTION OF 20-30 KT IN THE NE QUADRANT THROUGH THE NEXT 48 HRS. WILL BUILD SEAS HIGHER IN THE FORECAST (IN THE 9-14 FT RANGE) THAN WHAT IS INDICATED BY THE WAVEWATCH GUIDANCE. THERE COULD EASILY BE SOME ADJUSTMENTS TO FORECAST INTENSITY OF THE SYSTEM WHICH WILL IMPACT THE SEA STATE FORECAST ASSOCIATED WITH THE LOW. ...TROPICAL WAVES... TROPICAL WAVE HAS JUST ENTERED THE EXTREME ERN PACIFIC...AND IS ALONG 82W N OF 4N TO ACROSS THE BORDER OF COSTA RICA AND PANAMA. IT IS MOVING W AT 18 KT. THE WAVE REMAINS UNDER AN UPPER DIFFLUENT ZONE INDUCED BY AN UPPER LOW OVER THE NW CARIBBEAN...AND AN UPPER ANTICYCLONE OVER NICARAGUA. ONLY ISOLATED WEAK CONVECTION IS NOTED NEAR THE COAST OF CENTRAL PANAMA. LOW-LEVEL SPEED CONVERGENCE ASSOCIATED WITH A SHORT-LIVED PAPAGAYO GAP WIND EVENT MAY BE CONTRIBUTING TO ISOLATED WEAK CONVECTION ALONG AND NEAR THE COAST OF COSTA RICA. TROPICAL WAVE ALONG 101W FROM 3N TO 15N IS MOVING W ABOUT 17 KT. THIS POSITION IS BASED ON CONTINUITY AS THERE IS NOT ANY OBVIOUS EVIDENCE OF THE FEATURE IN THE AVAILABLE DATA. ONLY ISOLATED SHOWERS ARE WITHIN 60 NM W OF THE WAVE FROM 5N-11N. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N83W 07N100W 16N109W 10N120W 9N130W 7N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN 91W-97W. SCATTERED MODERATE CONVECTION IS S OF THE AXIS WITHIN 30 NM EITHER SIDE OF A LINE FROM 5N84W TO 5N87W. ...DISCUSSION... A WELL PRONOUNCED ELONGATED NE TO SW MID/UPPER LEVEL ANTICYCLONE EXTENDS FROM FAR NW MEXICO SW TO A CENTER NEAR 27N121W SW TO 26N128W TO W OF THE AREA AT 25N140W. TO THE W OF THE RIDGE...A LARGE DEEP LAYER TROUGH IS OBSERVED WELL W OF THE REGION. SW UPPER LEVEL FLOW BETWEEN THE TROUGH AND THE RIDGE CONTINUES TO ADVECT DEEP TROPICAL UPPER LEVEL MOSITURE NEWD FROM THE CENTRAL PACIFIC TO JUST NW OF THE FAR NW CORNER OF THE AREA. OTHERWISE ...SATELLITE WATER VAPOR IMAGERY SHOWS THAT THE VAST MAJORITY OF THE DISCUSSION AREA W OF A LINE FROM CENTRAL BAJA CALIFORNIA TO 20N121W TO 10N132W IS UNDER MODERATE SUBSIDENCE MAINTAINING STABLE ENVIRONMENTAL CONDITIONS AS INDICATED BY THE PRESENCE OF PATCHES OF SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING SW AROUND THE ERN PERIPHERY OF HIGH PRES PRESENT N OF 18N W OF 119W WITH THE PARENT HIGH CENTER LOCATED N OF THE AREA. OVER THE REMAINDER OF THE AREA ABUNDANT UPPER LEVEL MOISTURE IS OBSERVED ON SATELLITE IMAGERY...PRIMARILY ATTRIBUTED TO THE WESTWARD TRANSFER OF UPPER LEVEL MOSITURE UNDER BY UPPER LEVEL ELY WINDS ON THE SRN PERIPHERY OF THE ABOVE DESCRIBED UPPER LEVEL ANTICYCLONE. THE MOISTURE IS ALSO BEING ENHANCED BY DEBRIS CLOUDINESS FROM ITCZ CONVECTION E OF 120W AS WELL AS THAT DERIVED FROM CONVECTION ASSOCIATED WITH THE LOW NEAR 16N110W. THE COMBINATION OF HIGH PRES AS STATED ABOVE AND A SURFACE TROUGH THAT EXTENDS FROM 7N135W TO 13N133W IS RESULTING IN AN AREA OF NE-E TRADES OF 20 KT TO BE CONFINED FROM 15N-20N W OF 131W. THESE TRADES ARE FORECAST TO GRADUALLY DIMINISH IN AREAL COVERAGE DURING THE NEXT 48 HRS AS THE TROUGH EXITS THE AREA. THE PRES GRADIENT BETWEEN WEAK SURFACE HIGH PRES OVER SRN MEXICO AND THE 1007 MB LOW NEAR 16N110W HAS INCREASED THE LOW TO MID-LEVEL E-SE WINDS BETWEEN THE LOW AND THE SW COAST OF MEXICO DUE TO A TIGHT PRES GRADIENT INDUCED BETWEEN THE COAST AND THE CYCLONIC CIRCULATION AROUND THE LOW. THE PRESENT GULF OF PAPAGAYO EVENT OF NE 20-25 KT WINDS IS FORECAST TO DIMINISH IN ABOUT 18 HRS AS HIGH PRES OVER THE NRN CARIBBEAN SEA SHIFTS E. SRN HEMISPHERIC FRONTAL SYSTEMS CONTINUE TO SEND LONG-PERIOD SWLY SWELLS NWD WITH PERIODS OF 15-17 SECONDS BUILDING THE SEAS INTO THE 8-10 FT RANGE S OF 10N BETWEEN 90W-117W. THESE CONDITIONS ARE FORECAST TO BE PRESENT S OF 7N BETWEEN 91W-108W...AND S OF 6N BETWEEN 80W-87W IN ABOUT 48 HRS AND MAY IMPACT THE SW COAST OF MEXICO THROUGH EARLY NEXT WEEK. $$ AGUIRRE