000 AXPZ20 KNHC 120358 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI JUN 12 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 0330 UTC. ...SPECIAL FEATURE... A 1010 MB SURFACE LOW IS LOCATED NEAR 14N119W MOVING NW 5 TO 10 KT. LAST VISIBLE SATELLITE IMAGERY FROM LAST NIGHT SHOWED THAT THIS POSITION IS ASSOCIATED WITH A PARTIALLY EXPOSED CLOSED SURFACE CIRCULATION...THOUGH A BROAD OPEN CIRCULATION LIKELY EXTENDS SOUTHWESTWARD ALONG A SURFACE TROUGH FROM THE LOW TO 11N122W TO 10N126W. THE SATELLITE PRESENTATION OF THIS SYSTEM INDICATES THAT CONVECTION IS RATHER STRUNG OUT NEAR THIS TROUGH. ALSO...THE ENTRAINMENT OF DEEP LAYER DRY AIR IN NORTHWESTERLY FLOW ALOFT E OF AN UPPER ANTICYCLONE CENTERED NEAR 11N135W IS RESULTING IN A RATHER DISORGANIZED APPEARANCE TO DEEP CONVECTION NEAR THIS SYSTEM. THIS DRY AIR ENTRAINMENT IS EVIDENT IN EARLIER ENHANCEMENTS TO CONVECTIVELY-INDUCED OUTFLOW AND RESULTANT ARC CLOUDS. NEVERTHELESS...SCATTERED STRONG CONVECTION IS N OF THE CENTER WITHIN 30 NM OF 15N119W. SCATTERED MODERATE CONVECTION IS PRESENT WITHIN 120 NM SE AND 90 NM NW OF CENTER. EARLIER...WINDS OF 20 TO 25 KT WERE OCCURRING WITHIN 180 NM OF THE N AND W SEMICIRCLES OF THE LOW BASED ON A HIGH RESOLUTION QUIKSCAT PASS FROM AROUND 11/1330 UTC THU MORNING. HOWEVER... THIS SYSTEM HAS LOST A CONSIDERABLE AMOUNT OF ORGANIZATION SINCE THEN YIELDING A WEAKER SURFACE WIND FIELD. ADDITIONALLY...THIS SYSTEM IS FORECAST TO MOVE N DURING THE NEXT FEW DAYS. IN RESPONSE...IT WILL ENCOUNTER INCREASED DEEP LAYER SHEAR AND DRY AIR ASSOCIATED WITH AN UPPER TROUGH OVER NORTHERN PORTIONS OF THE DISCUSSION AREA...ALONG WITH COOLER SEA SURFACE TEMPERATURES. THESE FACTORS ARE FORECAST TO PROVIDE A MORE HOSTILE ENVIRONMENT FOR DEVELOPMENT WITH THIS SYSTEM. IN THE MEANTIME THE LOW IS STILL BEING MONITORED FOR TROPICAL CYCLONE FORMATION...BUT WITH A LOWER CHANCE THAN EARLIER. ...ITCZ... AXIS IS CENTERED ALONG 09N83W TO 07N97W TO 11N112W TO 09N128W TO 07N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN 83W AND 91W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM EITHER SIDE OF THE AXIS BETWEEN 95W AND 102W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF 13.5N111.5W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 08N BETWEEN 103W AND 106W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 08N TO 12N BETWEEN 122W AND 135W. ...DISCUSSION... N OF 20N... THE MAIN UPPER LEVEL FEATURES AT PRESENT INCLUDE AN UPPER LEVEL RIDGE N OF 20N W OF 134W...AN UPPER LEVEL TROUGH N OF 20N BETWEEN 118W AND 134W...AND AN UPPER LEVEL ANTICYCLONE CENTERED OVER CENTRAL MEXICO WITH AN ASSOCIATED UPPER RIDGE PROTRUDING WESTWARD INTO THE EAST PACIFIC REGION. DEEP SUBSIDENCE EAST OF THE FIRST RIDGE IS SUPPORTING A 1023 MB SURFACE HIGH NEAR 30N145W WITH A SURFACE RIDGE EXTENDING EASTWARD ACROSS THE NORTHERN WATERS. THE PRES GRADIENT AT THE SOUTHERN PERIPHERY OF THIS RIDGE WILL DRIVE NORTHEASTERLY TRADE WINDS OF 15 TO 20 KT GENERALLY IN AN AREA FROM 11N TO 20N W OF AROUND 130W DURING THE NEXT COUPLE DAYS WITH THE SURFACE RIDGE PERSISTING ACROSS THE NORTHERN WATERS. ADDITIONALLY...A STRENGTHENING SURFACE TROUGH OVER MEXICO IS EXPECTED TO STEEPEN THE PRES GRADIENT OFF THE S AND W COASTS OF BAJA CALIFORNIA...WHERE NWTO N WINDS TO 20 KT WILL OCCUR. AT 12/0000 UTC...THE SHIP WITH IDENTIFIER DHDE WAS REPORTING N WINDS OF 18 KT NEAR 27N115W...AND THE SHIP WITH IDENTIFIER A8MX4 WAS REPORTING N WINDS OF 20 KT NEAR 22N114W. THESE WINDS WILL INCREASE TO 20 TO 25 KT ON SATURDAY WHEN BROAD SYNOPTIC SCALE LIFT STRENGTHENS THE SURFACE TROUGH OVER MEXICO IN RESPONSE TO THE AFOREMENTIONED UPPER TROUGH BEING EJECTED EASTWARD OVER THE SW UNITED STATES AND NORTHERN MEXICO. ADDITIONALLY...THIS ASCENT IS FORECAST TO SUPPORT WEAK SMALLER SCALE SURFACE LOWS IN THE NORTHERN GULF OF CALIFORNIA DURING THE NEXT FEW DAYS...WHICH WILL BE ENHANCED AT NIGHT WHEN NOCTURNAL DRAINAGE FLOW IS MAXIMIZED. UPPER LEVEL JET MAXIMA ROUNDING THE BASE OF THE UPPER LEVEL TROUGH WILL CONTRIBUTE TO ENHANCED DOWNSLOPE FLOW INTO THE NORTHERN GULF OF CALIFORNIA...FURTHER SUSTAINING THE SURFACE LOWS AND CORRESPONDING THREAT FOR SW TO W WINDS OF 20 TO 25 KT ACROSS THE N GULF OF CALIFORNIA. THE HIGH RESOLUTION QUIKSCAT PASS AROUND 11/1300 THU MORNING UTC CONFIRMED THE PRESENCE OF THESE WINDS IN THE N GULF OF CALIFORNIA. HIGHER RESOLUTION GLOBAL AND REGIONAL MODEL GUIDANCE ALSO INDICATES THESE WINDS CONTINUING DURING THE NEXT FEW DAYS. S OF 20N... AN AREA OF LOW PRESSURE IS CURRENTLY BEING MONITORED FOR TROPICAL CYCLONE FORMATION. THE CORRESPONDING SURFACE LOW IS PRESENTLY NEAR 14N119W...WHICH IS DISCUSSED IN THE SPECIAL FEATURES SECTION ABOVE. ELSEWHERE...GENERALLY LIGHT WINDS ARE OCCURRING OUTSIDE OF CONVECTION ASSOCIATED WITH THE ITCZ. HOWEVER...S TO SW SWELL ASSOCIATED WITH WAVE HEIGHTS OF 8 TO 12 FT WILL CONTINUE TO OVERTAKE THE SOUTHERN PORTION OF THE DISCUSSION AREA DURING THE NEXT FEW DAYS. HOWEVER...MAXIMUM SEAS ARE FORECAST TO DIMINISH AS THESE WAVES DEPART THEIR SOURCE OF GENERATION FROM PREVIOUS SOUTHERN HEMISPHERIC STORMS. THESE WAVES WILL IMPACT THE COAST OF CENTRAL AMERICA SAT AND SUN RESULTING IN LARGE AND DANGEROUS BREAKING SURF CONDITIONS ARE ALONG THOSE COASTS. $$ COHEN/AGUIRRE