000 AXPZ20 KNHC 131608 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED MAR 13 2013 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... MONSOON TROUGH EXTENDS FROM 08N84W TO 07N90W TO 01N95W TO 02N101W...WHERE IT TERMINATES. ITCZ AXIS EXTENDS FROM 01N112W TO 03N121W TO 01N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 210 NM S OF TROUGH AXIS BETWEEN 82W AND 89W. ISOLATED TO SCATTERED MODERATE CONVECTION NOTED WITHIN 270 NM N OF ITCZ W OF 112W. ...DISCUSSION... GULF OF TEHUANTEPEC...HIGH PRESSURE IN THE WAKE OF A COLD FRONT OVER THE EASTERN BAY OF CAMPECHE IS CURRENTLY SURGING THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC...AND HAS INCREASED TO NEAR 40 KT EARLY THIS MORNING...WITH MAXIMUM SEAS BUILDING TO 14 FT. A REINFORCING NORTHERLY SURGE OVER THE GULF OF MEXICO WILL INCREASE THE GULF OF TEHUANTEPEC DRAINAGE FLOW TO 45 KT BY MIDNIGHT TONIGHT...AND FURTHER TO MINIMAL STORM FORCE DURING MAXIMUM DRAINAGE JUST BEFORE SUNRISE ON THU. THE STORM CONDITIONS ARE EXPECTED TO PERSIST THROUGH MID MORNING THU WITH LATEST GUIDANCE SUGGESTING THE GRADIENT WILL QUICKLY RELAX THU NIGHT AND FRI WITH THE LAST SURGE... AND TO ONLY MINIMAL GALE FORCE...OCCURRING AT SUNRISE FRI...WHICH IS A FULL 24 HOURS EARLIER THAN GUIDANCE SUGGESTED YESTERDAY. GULFS OF PAPAGAYO AND FONSECA...NE WINDS IN AND JUST DOWNSTREAM OF THE GULF OF PAPAGAYO HAVE INCREASED TO 20 TO 25 KT THIS MORNING...AND SPREAD WSW TO NEAR 10N89W. WINDS WILL REMAIN NEAR 20-25 KT THROUGH THIS EVENING THEN EXTEND FARTHER SW TO 09N90W BY THU MORNING WITH SEAS BUILDING TO 9 FT. THE GRADIENT WILL ALSO INCREASE FURTHER N REACHING THE GULF OF FONSECA AREA LATE THU. GUIDANCE SUGGESTS THE GRADIENT WILL RELAX SUPPORTING ONLY 15-20 KT IN THE GULF OF FONSECA ON THU NIGHT...THEN NE WINDS WILL INCREASE TO 20 TO 30 KT IN THE GULF OF PAPAGAYO EARLY FRI AND EXPAND NORTHWARD TO NEAR THE GULF OF FONSECA...WITH DOWNSTREAM SEAS BUILDING TO 10 FT. THIS EVENT THROUGH PAPAGAYO IS EXPECTED TO PERSIST THROUGH SUN NIGHT. GULF OF PANAMA...NORTHERLY WINDS AT 10 TO 15 KT WITH OCCASIONAL PULSES TO 15 TO 20 KT EXPECTED THROUGH THE WEEKEND. GULF OF CALIFORNIA...THE GRADIENT BETWEEN A PACIFIC RIDGE AND A TROUGH OVER MEANDERING ALONG THE SIERRA MADRE OCCIDENTAL OVER INTERIOR OLD MEXICO WILL SUPPORT N-NW WINDS AT 10 TO 15 KT ACROSS THE GULF OF CALIFORNIA THROUGH THU NIGHT. THE GRADIENT WILL RELAX ON FRI WITH LIGHT AND VARIABLE WINDS EXPECTED. A REINFORCING SHORTWAVE TROUGH IS MOVING INTO AN ANCHORED LONGWAVE TROUGH OVER CENTRAL N AMERICA. THE UPPER TROUGH HAS ITS MEAN AXIS EXTENDING SW ACROSS NW OLD MEXICO AND THE CENTRAL GULF OF CALIFORNIA TO 19N120W...THEN WEAKLY THROUGH THE MIDDLE LEVELS TO 09N125W. EXTENDING SSE FROM THE MEAN BASE OF THIS TROUGH ALONG 20N...AN UPPER LEVEL TROUGH EXTENDS TO A BASE OVER THE DEEP TROPICAL PACIFIC NEAR 02N98W. AN UPPER RIDGE IS AMPLIFYING NNE ACROSS THE WESTERN PORTION OF THE DISCUSSION AREA...WITH THE RIDGE CREST NOW EXTENDING ACROSS THE W COAST OF THE NW CONUS. A BROAD UPPER LEVEL RIDGE REMAINS ANCHORED ACROSS THE SW CARIBBEAN AND EXTENDS N ACROSS THE GULF OF MEXICO AND NW ACROSS CENTRAL AMERICA TO EASTERN OLD MEXICO. A SURFACE RIDGE EXTENDS FROM 32N132W TO 15N105W. THE ANCHORED RIDGE WILL BLOCK THE FORWARD ADVANCE OF AN APPROACHING COLD FRONT TO ONLY 142W TODAY. THE GRADIENT SW OF THE RIDGE IS SUPPORTING NE TRADES AT 15 TO 20 KT ACROSS THE TROPICS FROM 03N TO 20N BETWEEN 125W AND 140W...WITH SEAS 7 TO 9 FT IN NE SWELL. THE GRADIENT IS EXPECTED TO FURTHER RELAX TONIGHT WITH SEAS GRADUALLY SUBSIDING BELOW 8 FT BY FRI. $$ STRIPLING