000 AXPZ20 KNHC 040915 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU OCT 04 2012 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 08N78W TO 10N94W TO 11N107W TO 10N125W TO 07N140W. NO INTERTROPICAL CONVERGENCE ZONE AXIS IS PRESENT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS N OF 03N E OF 80W...WITHIN 60 NM EITHER SIDE OF A LINE FROM 13N96W TO 15N101W...AND ALSO WITHIN 20 NM S OF THE MONSOON TROUGH BETWEEN 103W AND 107W. ...DISCUSSION... AN UPPER LEVEL CYCLONE IS CENTERED N OF THE DISCUSSION WATERS NEAR 34N136W WITH AN UPPER TROUGH AXIS EXTENDING S AND SE THROUGH 27N131W AND 20N130W TO A BASE AT ANOTHER SMALL UPPER CYCLONE NEAR 13N139W. AN UPPER LEVEL ANTICYCLONE IS POSITIONED NEAR 21N113W WITH AN UPPER RIDGE EXTENDING N AND NW BEYOND 32N118W ALONG THE CALIFORNIA COAST. A SECOND UPPER LEVEL RIDGE EXTENDS SW TO A BROAD CREST ALONG 127W FROM 15N TO 24N. WEAK UPPER DIFFLUENCE IS NOTED OVER THE DEEP TROPICS ALONG THE SOUTHERN PERIPHERY OF THE ANTICYCLONE SUPPORTING THE CONVECTION ALONG THE MONSOON TROUGH AS IS DISCUSSED ABOVE. SOME OF THE DEBRIS MOISTURE ASSOCIATED WITH THIS CONVECTION IS BEING ADVECTED TO THE N AND NE AS A NARROW AND GRADUALLY THINNING TROPICAL PLUME ALONG THE W PERIPHERY OF THE UPPER RIDGE... ROUGHLY THROUGH THE POINTS 20N127W TO 26N125W TO OVER SAN DIEGO CALIFORNIA. AN UPPER LEVEL TROUGH REACHES FROM THE U.S. MISSISSIPPI VALLEY TO ACROSS THE FAR WESTERN GULF OF MEXICO AND CENTRAL MEXICO WITH A BASE IN THE NE PACIFIC NEAR 15N106W. THIS TROUGH IS EFFECTIVELY SEPARATING THE UPPER FLOW OVER THE DEEP TROPICAL PACIFIC. A PERSISTENT TROPICAL PLUME IS PUSHING TROPICAL MOISTURE FROM THE MONSOON TROUGH REGION N AND NE AHEAD OF THE UPPER TROUGH TO ACROSS SE MEXICO AND THE CENTRAL AND EASTERN GULF OF MEXICO. TO THE E OF THIS TROUGH IS AN UPPER LEVEL RIDGE EXTENDING NW FROM SOUTH AMERICA TO NEAR 04N99W...WITH DEBRIS MOISTURE...ASSOCIATED WITH CONVECTION THAT DEVELOPED OVER INTERIOR NW SOUTH AMERICA AND SOUTHERN CENTRAL AMERICA SPREADING WESTWARD TO 91W. ELSEWHERE AT THE LOW LEVELS...BROAD SURFACE RIDGING COVERS THE MAJORITY OF THE AREA N OF 20N W OF 110W. SOUTHWESTERLY LOW LEVEL WINDS AT 15 TO 20 KT ALONG WITH CROSS EQUATORIAL SW SWELL CONTINUES TO RESULT IN 8 FT SEAS ACROSS THE S CENTRAL WATERS. THESE SEAS WILL GRADUALLY DECAY TO LESS THAN 8 FT BY EARLY SAT MORNING. BY 48 HOURS...NORTHERLY WINDS ARE FORECAST TO INCREASE TO 20 TO 25 KT W OF THE NORTHERN BAJA CALIFORNIA PENINSULA AS RIDGING TO THE W AND NW TIGHTENS AND LOW PRES TROUGHING OVER NW MEXICO BECOMES MORE PRONOUNCED. A PIECE OF VORTICITY ASSOCIATED WITH THE TEHUANTEPEC EVENT MAY HELP TO INDUCE THE FORMATION OF LOW PRES ALONG THE MONSOON TROUGH BY 24 THROUGH 48 HOURS WITH FRESH TO STRONG WINDS POSSIBLE ON THE NORTHERN SIDE OF THE LOW AS IT MOVES WESTWARD AROUND 10 TO 15 KT INTO THE WEEKEND. A WEAK SURFACE TROUGH...THE REMNANTS OF MIRIAM...REACHES FROM 19N122W TO 16N120W WITH LIGHT TO MODERATE WINDS IN THE VICINITY OF THE TROUGH. OTHER THAN SOME SCATTERED SHOWERS...NO SIGNIFICANT IMPACTS OF THIS TROUGH ARE ANTICIPATED. GAP WINDS...FRESH TO STRONG NORTHERLY WINDS CONTINUE IN AND DOWNWIND OF THE GULF OF TEHUANTEPEC AND ARE FORECAST TO PERSIST THROUGH THE END OF THE WEEK WITH A TIGHT PRES GRADIENT BETWEEN STRONG HIGH PRES OVER MEXICO AND LOWER PRES JUST TO THE S ASSOCIATED WITH THE MONSOON TROUGH. THESE WINDS WILL DIMINISH TO 20 TO 25 KT BY EARLY SAT MORNING. MEANWHILE SEAS OF 8 TO 11 FT WHICH ACCOMPANY THESE WINDS WILL GRADUALLY SUBSIDE TO 8 FT BY 48 HOURS AS THE WINDS DIMINISH IN COVERAGE AND INTENSITY. IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO...NE TO E WINDS AT 20 TO 25 KT WILL OCCUR THROUGH TODAY FUNNELING THROUGH THE CENTRAL AMERICAN PASSES FROM THE W CARIBBEAN SEA...DIMINISHING TO 20 KT OR LESS BY 24 HOURS AS TRADES IN THE CARIBBEAN SEA BACK OFF. $$ LEWITSKY