000 AXPZ20 KNHC 050312 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN JUL 05 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 0300 UTC. ...TROPICAL WAVES... A TROPICAL WAVE OVER ERN PACIFIC IS ALONG 91W N OF 5N MOVING W AT ABOUT 16 KT. NO EVIDENCE OF CYCLONIC TURNING IN THE LOW CLOUD FIELD IS EVIDENT IN THE LATEST SATELLITE IMAGERY. THE WAVE CONTINUES TO GENERATE ITS MAIN CONVECTIVE ACTIVITY WHERE IT CROSSES THE ITCZ. ISOLATED SHOWERS ARE WITHIN 120 NM E OF THE WAVE FROM 10N-12N. THE TROPICAL WAVE PREVIOUSLY ALONG ALONG 119W IS NO LONGER IDENTIFIABLE BOTH ON SATELLITE IMAGERY AND OTHER AVAILABLE DATA SOURCES. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N78W 8N91W 14N105W 10N120W 8N130W 6N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 90W-100W. SCATTERED MODERATE CONVECTION IS S OF THE AXIS WITHIN 30 NM EITHER SIDE OF A LINE FROM 5N85W TO 5N89W. ...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. THE COMBINATION OF WEAK HIGH PRES PRESENT W OF 123W AND SURFACE TROUGH EXTENDING FROM 17N135W TO 10N132W IS ALLOWING FOR NE-E TRADES OF 20 KT TO BE CONFINED TO A LIMITED AREA FROM 14N-19N W OF 134W. THESE TRADES ARE FORECAST TO CHANGE LITTLE OVER THE NEXT 24 HRS...THEN EXPAND N TO 18N W OF ABOUT 137W IN 48 HRS. NW 20 KT WINDS ARE OVER THE FAR NE CORNER OF THE AREA TO THE COAST OF BAJA CALIFORNIA ARE FORECAST TO CHANGE LITTLE DURING THE NEXT 48 HRS 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 A 1008 MB LOW NEAR 14N106W IS INCREASING LOW TO MID-LEVEL E-SE WINDS SW OF MEXICO. SATELLITE IMAGERY FROM EARLY THIS EVENING IS REVEALING THAT THE LOW REMAINS RATHER LIMITED IN DEEP CONVECTION...BUT ITS OVERALL CLOUD PATTERN IS SHOWING SOME SYMMETRY COMPARED TO 24 HRS AGO. CROSS EQUATORIAL SLY FLOW INTERACTING WITH THE INCREASING E TO SE FLOW IS RESULTING IN AN INCREASE OF LOW-LEVEL CYCLONIC VORTICITY WELL OFF THE MEXICAN COAST. THE LOW IS FORECAST POSSIBLE BECOME A TROPICAL CYCLONE AS IT REACHES TO NEAR 16N110W IN 24 HRS...AND TO NEAR 16N113W IN 48 HRS. WINDS OF 20-25 KT ARE FORECAST IN THE NE QUADRANT OF THE LOW WITHIN A DISTANCE OF ABOUT 180 NM TO 360 NM. 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 BY 48 HRS 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 SUN 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 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...AND EXPANDING N TO 10N BETWEEN 91W-106W AND TO S OF 7N BETWEEN 80W91W IN ABOUT 48 HRS. THESE CONDITIONS MAY LEAD TO LARGE BATTERING WAVES IMPACTING THE SW COAST OF MEXICO FROM SUN INTO EARLY NEXT WEEK. $$ AGUIRRE