000 AXPZ20 KNHC 042204 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT JUL 04 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. ...TROPICAL WAVES... A TROPICAL WAVE OVER ERN PACIFIC IS ALONG 89W N OF 6N MOVING W AT ABOUT 16 KT. NO EVIDENCE OF CYCLONIC TURNING IN THE LOW CLOUD FIELD IS EVIDENT IN THE LATEST VISIBLE SATELLITE IMAGERY. THE WAVE CONTINUES TO GENERATE ITS MAIN CONVECTIVE ACTIVITY WHERE IT CROSSES THE ITCZ. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS... AND IS PRIMARILY BEING DRIVEN BY LOW-LEVEL CONVERGENCE NEAR THE ITCZ. WITH THE WAVE BEING UNDER A SLIGHTLY UPPER DIFFLUENT ZONE EXPECT CONVECTION TO POSSIBLE INCREASE THROUGH SUN MORNING. A TROPICAL WAVE EXTENDS ALONG 119W FROM 6N TO 17N MOVING W 10-15 KT. ONLY ISOLATED SHOWERS AND TSTMS ARE WITHIN 60 NM E OF THE WAVE FROM 10N-13N. CONVECTION IS CONFINED TO WHERE THE WAVE INTERSECTS THE ITCZ. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N78W 8N90W 12N100W 10N109W 10N121W 8N128W 6N140W. SCATTERED STRONG CONVECTION IS WITHIN 120 NM N OF THE AXIS BETWEEN 91W-97W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF THE AXIS WITHIN 30 NM EITHER SIDE OF A LINE FROM 6N104W TO 6N107W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 119W-121W. ...DISCUSSION... A WELL PRONOUNCED NE TO SW ELONGATED MID/UPPER LEVEL ANTICYCLONE IS OVER SW TEXAS WITH A RIDGE EXTENDING SW TO ACROSS CENTRAL BAJA CALIFORNIA TO 25N120W TO 23N132W TO SW OF THE AREA AT 21N140W. AN AMPLIFYING LARGE DEEP LAYER TROUGH IS WELL W OF THE REGION. PERSISTENT UPPER LEVEL SW FLOW IS NOTED TO THE N OF RIDGE...AND CONTINUES TO ADVECT DEEP TROPICAL UPPER LEVEL MOSITURE FROM THE CENTRAL PACIFIC NEWD INTO THE AREA FROM 23N TO 28N E TO NEAR 130W. OTHERWISE...SATELLITE WATER VAPOR IMAGERY SHOWS THAT THE VAST MAJORITY OF THE DISCUSSION AREA W OF A LINE FROM 26N110W TO 16N123W TO 8N134W IS UNDER MODERATE SUBSIDENCE RESULTING IN RATHER STABLE ENVIRONMENTAL CONDITIONS AS INDICATED BY THE PRESENCE OF PATCHES OF SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING S AROUND THE ERN PERIPHERY OF WEAK SURFACE HIGH PRESSURE PRESENT N OF 17N W OF 120W. SCATTERED TO BROKEN STRATOCUMULUS CLOUDS ARE ERODING OVER THE FAR NE PART OF THE AREA N OF 21N E OF 120W TO ALONG THE COAST OF BAJA CALIFORNIA. OVER THE REMAINDER OF THE AREA ABUNDANT UPPER LEVEL MOISTURE IS OBSERVED ON SATELLITE IMAGERY...PRIMARILY ATTRIBUTED TO MODERATE TO STRONG ELY SHEAR OCCURRING ON THE SRN PERIPHERY THE ANTICYCLONE OVER SW TEXAS...BUT IS ALSO BEING ENHANCED IN THE ITCZ REGION AND SURROUNDING AREAS WHICH REMAIN UNDER A BROAD LOW PRES FIELD. AN UPPER LEVEL CYCLONIC CIRCULATION OVER THE FAR WRN CARIBBEAN SEA IS CONTRIBUTING FURTHER TO THIS MOISTURE BY ADVECTING ADDITIONAL MOISTURE FROM ONGOING CONVECTION OVER THE FAR SW CARIBBEAN SEA...AND OVER CENTRAL AMERICA S OF HONDURAS SWD INTO THE FAR ERN PACIFIC. BOUNDARY LAYER WINDS CONTINUE TO BE ON THE LIGHT SIDE ACROSS THE SUBTROPICS DUE TO WEAK LOW PRES AND AN ASSOCIATED DISSIPATING FRONT NW OF THE AREA INTERRUPTING THE SUBTROPICAL RIDGING. NW 20 KT WINDS ARE FORECAST TO INCREASE OVER THE FAR NE CORNER OF THE AREA LATE SUN INTO MON AS THE SUB-TROPICAL HIGH TAKES MORE HOLD OF THE AREA...BEING THE MORE TYPICAL SCENARIO. THE PRES GRADIENT BETWEEN WEAK SURFACE HIGH PRES OVER SRN MEXICO AND DEVELOPING LOW PRES NEAR 14N105W IS INCREASING LOW TO MID-LEVEL E-SE WINDS SW OF MEXICO. SHIP WITH CALL LETTER ID "3FQO4" JUST OFF THE COAST SW MEXICO NEAR 16.5N100W AT 1900 UTC REPORTED SE WINDS NEAR 30 KT. SATELLITE IMAGERY FROM THIS AFTERNOON IS REVEALING THAT THE LOW IS BEGINNING TO CONSOLIDATE WITH TIME. THIS PROCESS IS EXPECTED TO CONTINUE WITHIN THE NEXT 48 HOURS AS CROSS EQUATORIAL SLY FLOW INTERACTS WITH THE INCREASING E TO SE FLOW INCREASING LOW-LEVEL CYCLONIC VORTICITY WELL OFF THE MEXICAN COAST. THE LOW IS FORECAST TO BE NEAR 15N109W IN 24 HRS...AND NEAR 16N112W IN 48 HRS. WINDS OF 20-30 KT ARE FORECAST TO BE IN THE NE QUADRANT OF THE LOW WITHIN A DISTANCE OF ABOUT 180 NM NE TO 360 NM DUE TO THE RESULTANT PRES GRADIENT BETWEEN THE LOW AND THE GEOGRAPHIC INFLUENCE OF THE MEXICAN COAST. LATEST WAVEWATCH GUIDANCE SHOWS SEAS BUILDING TO 8-10 FT IN THE NE QUADRANT OF THE LOW...BUT WILL FORECAST SEAS UP TO 12 FT DUE TO THE INCREASING FETCH. CROSS EQUATORIAL FLOW IS BRINGING SE TO S WINDS TO 20 KT FROM 2N TO 8N BETWEEN 105W AND 125W...AND S OF 6N W OF 134W. ALSO... MODERATE EASTERLY LOW/MID-LEVEL FLOW OVER THE W CARIBBEAN WILL BLEED INTO THE GULF OF PAPAGAYO...WITH SURFACE WINDS BEING ACCELERATED INTO THE 20-25 KT RANGE NEAR AND DOWNSTREAM OF THE GULF OF PAPAGAYO OVERNIGHT INTO SAT DUE TO VARIATIONS IN LOCAL TOPOGRAPHY. THESE WINDS WILL BE MAXIMIZED LATE AT NIGHT WHEN NOCTURNAL DRAINAGE FLOW IS AT ITS PEAK...AND ARE FORECAST TO DIMINISH LATE SUN. STRONG SOUTHERN HEMISPHERIC FRONTAL SYSTEMS CONTINUE TO SEND LONG-PERIOD SWLY SWELLS NWD WITH PERIODS OF 15-17 SECONDS WITH SEAS IN THE 8-10 FT RANGE S OF 12N BETWEEN 95W-123W. THESE SEAS ARE EXPECTED TO BE WITHIN THE AREA S OF 5N BETWEEN 94W-115W IN 48 HRS...AND MAY IMPACT THE SW COAST OF MEXICO BEGINNING ON SUN AS LARGE BATTERING WAVES. $$ AGUIRRE