000 AXPZ20 KNHC 052203 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN JUL 05 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...SPECIAL FEATURE... AN AREA OF LOW PRESSURE CENTERED NEAR 16N110W...OR ABOUT 375 MILES SW OF MANZANILLO MEXICO HAS ONLY SLIGHT IMPROVEMENT TO ITS CLOUD STRUCTURE DURING THE COURSE OF THE DAY. LATEST SATELLITE IMAGERY REVEALS A BAND REMOVED FROM THE CENTER CONSISTING OF SCATTERED STRONG CONVECTION WITHIN 30 NM EITHER SIDE OF A LINE FROM 14N109W TO 16N107W...AND WITHIN 45 NM EITHER SIDE OF LINE FROM 16N07W TO 18N108W. SCATTERED STRONG CONVECTION IN SMALL CLUSTERS IS WITHIN 75 NM S OF AND 120 NM W OF THE CENTER. SCATTEROMETER DATA FROM THIS MORNING 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 CYCLONE AS IT MOVES TO NEAR 18N114W IN 24 HRS...AND TO NEAR 18N119W IN 48 HRS. WILL KEEP MENTION OF 20-30 KT IN THE NE QUADRANT THROUGH THE NEXT 48 HRS. WILL BUILD HIGHER SEAS IN THE FORECAST (IN THE 9-14 FT RANGE) THAN WHAT IS INDICATED BY THE WAVEWATCH GUIDANCE...SEAS MAY EVEN BE AT HIGHER LEVELS IF THE LOW INTENSIFIES MUCH SOONER THAN ANTICIPATED. ...TROPICAL WAVES... TROPICAL WAVE HAS JUST ENTERED THE EXTREME ERN PACIFIC...AND IS ALONG 80W N OF 03N 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. THIS IS SUPPORTING SCATTERED STRONG CONVECTION ALONG THE COAST OF NRN COSTA RICA. ISOLATED SHOWERS ARE WITHIN 120 NM W OF THE WAVE. LOW-LEVEL SPEED CONVERGENCE ASSOCIATED WITH A SHORT-LIVED PAPAGAYO GAP WIND EVENT MAY BE CONTRIBUTING TO SCATTERED MODERATE CONVECTION NW OF THE WAVE NEAR THE COAST OF COSTA RICA. TROPICAL WAVE ALONG 99W FROM 3N TO 15N IS MOVING W 15-20 KT. THIS POSITION IS BASED ON CONTINUITY AS THERE IS NOT ANY OBVIOUS EVIDENCE OF THE FEATURE IN THE AVAILABLE DATA. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N83W 07N100W 16N109W 10N120W 9N130W 7N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN 83W-94W...AND ALSO FROM 7N-11N BETWEEN 99W-101W. ...DISCUSSION... A WELL PRONOUNCED ELONGATED NE TO SW MID/UPPER LEVEL ANTICYCLONE EXTENDS FROM FAR SW TEXAS SW TO ACROSS CENTRAL BAJA CALIFORNIA TO 26N125W TO 25N132W TO W OF THE AREA AT 21N140W. 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 INTO 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 19N124W TO 9N134W 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 17N W OF 118W WITH THE HIGH CENTER OF 1022 MB ANALYZED NEAR 29N131W. 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 ENHANCED BY DEBRIS CLOUDINESS FROM ITCZ CONVECTION E OF 110W AS WELL AS THAT ASSOCIATED WITH THE LOW NEAR 16N110W. THE COMBINATION OF HIGH PRES AS STATED ABOVE AND A SURFACE TROUGH THAT EXTENDS FROM 6N135W TO 12N133W 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 BEGINS TO EXIT THE AREA. THE PRES GRADIENT BETWEEN WEAK SURFACE HIGH PRES OVER SRN MEXICO AND THE 1008 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 THAT HAS SET UP THERE. THE PRESENT GULF OF PAPAGAYO EVENT OF NE 20-25 KT WINDS AS DEPICTED IN AN ASCAT PASS FROM NEAR 1600 UTC THIS MORNING IS FORECAST TO DIMINISH IN ABOUT 24 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 8N BETWEEN 90W-108W...AND S OF 6N BETWEEN 79W-87W IN ABOUT 48 HRS AND MAY IMPACT THE SW COAST OF MEXICO THROUGH EARLY NEXT WEEK. $$ AGUIRRE