000 AXPZ20 KNHC 160950 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU AUG 16 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 0945 UTC. ...SPECIAL FEATURE... THE CENTER OF TROPICAL DEPRESSION HECTOR IS NEAR 19.0N 115.8W AT 0900 UTC MOVING N NW OR 335 DEG AT 04 KT WITH MAXIMUM SUSTAINED WINDS OF 25 KT WITH GUSTS TO 35 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. HECTOR CONTINUES TO EXPERIENCE EASTERLY SHEAR WITH SCATTERED STRONG CONVECTION CURRENTLY FLARING WITHIN 120 NM OVER THE SW QUADRANT AND ISOLATED MODERATE TO STRONG INTERMITTENT CONVECTION IS NOTED ELSEWHERE WITHIN 150 NM OF CENTER. HECTOR IS EXPECTED TO CHANGE LITTLE AS IT STEERED SLOWLY THROUGH AN AREA OF INCREASINGLY COOLING SURFACE WATERS. HECTOR IS EXPECTED TO WEAKEN TO A REMNANT LOW PRESSURE CENTER TONIGHT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A MONSOON TROUGH AXIS EXTENDS W FROM EXTREME NW COLOMBIA 09N90W THROUGH A PERSISTENT EMBEDDED LOW PRES WITHIN THE TROUGH AXIS NEAR 07N98W...THEN THE AXIS TURNS NW TO NEAR 10N108W WHERE IT LOSES IDENTITY IN STRONG SOUTHWESTERLY MONSOONAL FLOW. THE MONSOON TROUGH AXIS BECOMES DEFINED AGAIN WELL SW OF DISSIPATING TROPICAL DEPRESSION HECTOR...NEAR 12N120W AND CONTINUES SW TO NEAR 09N140W WHERE LOW LEVEL CROSS EQUATORIAL SOUTHEASTERLY WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES W WELL BEYOND 140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED OVER WITHIN 240 NM OF THE CENTRAL AMERICAN COAST FROM 04N TO 16N...AND ALSO WITHIN 45 NM EITHER SIDE OF A OF LINE FROM 23N106W TO 11N116W TO 10N134W. NUMEROUS LIGHTNING STRIKES ARE DETECTED WITHIN THE CLUSTERS BETWEEN 14N AND 16N. ...DISCUSSION... A DEEP LAYERED CYCLONE IS QUASI STATIONARY JUST N OF THE AREA AT 35N130W WITH AN UPPER TROUGH EXTENDING S INTO THE DISCUSSION ALONG 32N130W TO A BASE 15N138W. AN ASSOCIATED SURFACE LOW PRESSURE DEVELOPED AS FORECAST AT 36N128W WITH A WEAK SURFACE TROUGH NOW EXTENDING INTO THE AREA FROM 32N130W TO 30N140W. EXPECT A SERIES OF TROUGHS TO ROTATE INTO THE DISCUSSION AREA OVER THE NEXT COUPLE OF DAYS ACCOMPANIED BY A SW TO NW 10 TO 15 KT WIND SHIFT AND COMBINED SEAS INCREASING TO 7 FT IN THE ACCOMPANYING N SWELL. AN UPPER CUT OFF CYCLONE CONTINUES TO DRIFT W NEAR 19N126W WITH AN UPPER TROUGH EXTENDING S TO BASE AT 09N127W. AN UPPER ANTICYLONE HAS SHIFTED S TO OVER NORTHWESTERN OLD MEXICO WITH AN UPPER RIDGE EXTENDING SW ACROSS THE CENTRAL BAJA CALIFORNIA PENINSULA TO A SHARP CREST OVER THE PACIFIC AT 25N125W. SOME DEBRIS MOISTURE IS OBSERVED STREAMING N ALONG THE W PERIPHERY OF THE UPPER RIDGE...WITHIN 120 NM OF A LINE FROM 30N117W TO BEYOND 34N117W...THEN TURNS E ACROSS ARIZONA AND SOUTHERN NEW MEXICO. OTHERWISE THE PREVIOUSLY DESCRIBED UPPER FEATURES ALL COMBINE TO DRY OUT THE UPPER LEVELS OF THE DISCUSSION AREA N OF 20N W OF 121W AND FROM 13N TO 20N W OF 125W. FURTHER E...THE UPPER DIFFLUENCE ENHANCED CONVECTION OVER INTERIOR OLD MEXICO AND CURRENTLY ALONG THE PACIFIC CONVECTION PREVIOUSLY MENTIONED BETWEEN 109W AND 116W. THE RESULTANT DENSE DEBRIS MOISTURE IS FANNING OUT OVER THE AREA N OF 20N BETWEEN 100W AND 113W... BEFORE TURNING E INTO A NARROWING PLUME THAT CONTINUES ESE ACROSS CENTRAL TEXAS THE EXTREME SE CONUS. AN UPPER CYCLONE OVER THE SW GULF OF MEXICO HAS A UPPER TROUGH EXTENDING S ACROSS OLD MEXICO AT 18N97W INTO AN UPPER CYCLONE OVER THE DEEP TROPICAL PACIFIC AT 06N100W. THE PATTERN IS SHIFTING W WITH TIME WITH DRY UPPER AIR NOTED WITHIN 150 NM W OF THE TROUGH. IMMEDIATELY TO THE E AN UPPER CYCLONE OVER THE SE GULF OF MEXICO RIDGES SW OVER THE DEEP TROPICAL PACIFIC BETWEEN 80W AND 90W. UPPER DIFFLUENCE E OF THE TROUGH IS ENHANCING THE INTENSE CONVECTION ALREADY MENTIONED OVER THE WESTERN GULF OF TEHUANTEPEC...WHILE WEAK UPPER DIFFLUENCE UNDER THE RIDGE IS SUPPORTING THE ISOLATED CONVECTION ALONG THE MONSOON TROUGH ALSO PREVIOUSLY DESCRIBED. THE DEBRIS MOISTURE SPREADS S ACROSS THE EQUATOR AND ACROSS THE GALAPAGOS ISLANDS. THE ENVELOPE OF CYCLONIC 20 KT OR GREATER WINDS ASSOCIATED WITH TROPICAL STORM HECTOR EXTENDS ONLY ABOUT 75 NM FROM THE CENTER BUT MERGES WITH A LARGE AREA STRONG SOUTHWESTERLY MONSOONAL FLOW NOTED FROM 10N TO 23N BETWEEN 103W AND 117W. THESE SW FLOW WILL DIMINISH TONIGHT AS HECTOR GRADUALLY WEAKENS. LONG PERIOD SW SWELLS ARE NOTED OVER THE AREA S OF 15N BETWEEN 91W AND 103W AND ALSO S OF 09N BETWEEN 80W AND 89W...WITH THE SWELL TRAIN INTERRUPTED BY THE GALAPAGOS ISLANDS. THESE SWELLS ARE EXPECTED TO DAMPEN WITH SEAS SUBSIDING TO LESS THAN 8 FT TONIGHT. $$ NELSON