000 AXPZ20 KNHC 041533 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 09N79W TO 06N92W TO 15N105W TO 09N120W TO 10N126W TO 07N137W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N137W TO 06N140W. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS FROM 05N TO 08N E OF 81W. SCATTERED MODERATE CONVECTION IS FROM 06N TO 10N BETWEEN 83W AND 86W...WITHIN 60 NM EITHER SIDE THE MONSOON TROUGH AXIS BETWEEN 86W AND 90W...AND FROM 13N TO 15N BETWEEN 103W AND 108W. ...DISCUSSION... A BROAD UPPER LEVEL CYCLONE IS CENTERED N OF THE DISCUSSION WATERS NEAR 35N136W WITH AN UPPER LEVEL TROUGH AXIS EXTENDING S AND SE THROUGH 25N130W AND TO A BASE NEAR 13N133W. AN UPPER LEVEL ANTICYCLONE IS POSITIONED NEAR 20N112W WITH AN UPPER RIDGE EXTENDING N-NW BEYOND 32N118W ALONG THE SOUTHERN CALIFORNIA COAST. A SECOND UPPER LEVEL RIDGE EXTENDS SW TO A BROAD CREST ALONG 127W FROM 14N TO 19N. 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 STREAM OF TROPICAL MOISTURE ON THE WESTERN PERIPHERY OF THE UPPER RIDGE...ROUGHLY THROUGH THE POINTS 20N125W TO 26N125W TO 32N117W. AN UPPER LEVEL TROUGH REACHES FROM THE U.S. MISSISSIPPI RIVER VALLEY TO OVER THE FAR WESTERN GULF OF MEXICO AND CENTRAL MEXICO WITH A BASE IN THE NE PACIFIC NEAR 16N102W. THIS TROUGH IS EFFECTIVELY SEPARATING THE UPPER FLOW OVER THE DEEP TROPICAL PACIFIC. A PERSISTENT TROPICAL PLUME OF MOISTURE IS ADVECTING FROM THE MONSOON TROUGH REGION N AND NE AHEAD OF THE UPPER TROUGH TO ACROSS SOUTHERN 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 05N104W...WITH DEBRIS MOISTURE...ASSOCIATED WITH CONVECTION OCCURRING IN CLOSE PROXIMITY TO THE MONSOON TROUGH AXIS ALONG 08N/09N BETWEEN 75W AND 86W SPREADING WESTWARD TO 93W. ELSEWHERE AT THE LOW LEVELS...BROAD SURFACE RIDGING COVERS MUCH OF THE DISCUSSION 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 AN AREA OF SEAS TO 9 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 IS EXPECTED TO DRIFT SLOWLY WESTWARD AND MAY HELP TO INDUCE THE FORMATION OF A WEAK SURFACE TROUGH OR WEAK LOW PRESSURE AREA ALONG THE MONSOON TROUGH BY 24 THROUGH 48 HOURS WITH FRESH TO STRONG WINDS POSSIBLE ON THE NORTHERN PERIPHERY OF THE FEATURE AS IT DEVELOPS AND MOVES WESTWARD AROUND 10 TO 15 KT INTO THE WEEKEND. 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 PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE OVER MEXICO AND LOWER PRESSURE 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 WESTERN CARIBBEAN SEA...DIMINISHING TO 20 KT OR LESS BY THIS EVENING AS TRADES IN THE CARIBBEAN SEA DIMINISH AS WELL. $$ HUFFMAN