000 AXPZ20 KNHC 030924 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU JUL 03 2014 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. ...SPECIAL FEATURES... TROPICAL STORM DOUGLAS IS CENTERED NEAR 20.4N 116.5W...OR ABOUT 395 NM...735 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 03/0900 UTC MOVING NW OR 315 DEGREES AT 3 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. WEAKENING IS FORECAST DURING THE NEXT COUPLE OF DAYS...AND DOUGLAS IS EXPECTED TO BECOME A TROPICAL DEPRESSION TODAY AND DEGENERATE INTO A REMNANT LOW BY FRIDAY MORNING. SCATTERED MODERATE CONVECTION WAS WITHIN 150 NM NE SEMICIRCLE AND 45 NM SW SEMICIRCLE OF CENTER. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS FROM 07N78W TO 09N95W TO 08N105W TO 09N112W THEN CONTINUES FROM 12N120W TO 11N130W. ITCZ AXIS FROM 10N135W TO BEYOND 09N140W. SCATTERED MODERATE FROM 04N TO 06N BETWEEN 88W AND 93W. SCATTERED MODERATE ISOLATED STRONG FROM 08N TO 12N BETWEEN 107W AND 111W. SCATTERED MODERATE FROM 05N TO 08N BETWEEN 106W AND 113W. ...DISCUSSION... A CUT-OFF LOW IS SPINNING NEAR 19N135W WITH A TROUGH EXTENDING SW TO BEYOND 15N140W. W TO SW FLOW ALOFT IS NOTED OVER THE NW PART OF THE AREA. AN UPPER ANTICYCLONE CENTERED NEAR 13N128W EXTENDS A RIDGE NORTHEASTWARD TOWARD NORTHERN BAJA CALIFORNIA. ANOTHER RIDGE EXTENDS FROM THE SAME ANTICYCLONE EASTWARD ALONG 13N THEN NORTHEASTWARD TOWARD LAS MARIAS ISLANDS. UPPER DIFFLUENCE ASSOCIATED WITH THE RIDGE EXTENDING EASTWARD IS HELPING TO INDUCE CONVECTION ALONG THE MONSOON TROUGH... PARTICULARLY BETWEEN 107W AND 111W. SOUTHERLY FLOW ON THE EAST SIDE OF DOUGLAS HAS TRANSPORTED LOW LEVEL MOISTURE NORTHWARD INTO THE GULF OF CALIFORNIA. THIS SURGE OF MOISTURE IS PRODUCING SCATTERED MODERATE CONVECTION NEAR LAS MARIAS ISLANDS AND ACROSS THE GULF OF CALIFORNIA BETWEEN 24N AND 28N. AT THE SURFACE...A 1027 MB HIGH PRES LOCATED NEAR 36N140W EXTENDS A RIDGE ACROSS THE N WATERS THROUGH 31N128W TO N OF TROPICAL STORM DOUGLAS NEAR 25N114W. GENTLE TO MODERATE TRADE WINDS PERSIST S OF THE RIDGE AXIS. A SURFACE TROUGH IS ANALYZED FROM 13N130W TO 08N135W. ONLY FEW SHOWERS ARE ASSOCIATED WITH THIS FEATURE. THE REMNANTS OF ELIDA ARE STILL NOTED USING NIGHT CHANNEL VISIBLE IMAGERY. A 1011 MB LOW PRES IS ANALYZED ON THE 0600 UTC SURFACE MAP NEAR 16.5N103W. SCATTERED SHOWERS WITH ISOLATED TSTMS ARE WITHIN ABOUT 90 NM JUST TO THE N OF THE LOW CENTER. THE LOW IS FORECAST TO OPEN UP INTO A TROUGH IN ABOUT 24 HOURS AS THE SHEAR ALOFT TAKES ITS TOLL ON THE SYSTEM. THE TROUGH WILL MOVE WESTWARD OVER THE NEXT 48-72 HOURS...REACHING NEAR 110W. LONG PERIOD CROSS EQUATORIAL SOUTHERLY SWELL WILL CONTINUE TO PROPAGATE N ACROSS THE TROPICAL WATERS E OF 130W...BUILDING SEAS UP TO 11 FT. THE LEADING EDGE OF THE NEXT SOUTHERLY SWELL TRAIN HAS CROSSED THE EQUATOR WITH PERIODS IN THE 20-22 SECOND RANGE. THIS SWELL EVENT WILL REACH THE COAST OF COSTA RICA AND WESTERN PANAMA THIS EVENING AND COVER THE ENTIRE COAST S OF 28N AND THE SOUTHERN PORTION OF THE GULF OF CALIFORNIA BY FRI EVENING... BRINGING ROUGH SURF CONDITIONS. GAP WINDS...WINDS WILL APPROACH 25 KT DURING THE OVERNIGHT HOURS LATE THU NIGHT INTO FRI MORNING...THEN AGAIN LATE FRI NIGHT INTO SAT IN BOTH THE GULF OF TEHUANTEPEC AND THE GULF OF PAPAGAYO. THIS COULD BE ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE ACROSS NORTHERN CENTRAL AMERICA AND THEN ACROSS THE ISTHMUS OF TEHUANTEPEC. IN ADDITION...HIGH PRESSURE IS FORECAST TO BUILD OVER THE NORTHERN GULF OF MEXICO INCREASING THE PRES GRADIENT ACROSS THE REGION. CURRENTLY...SOME CONVECTIVE ACTIVITY IS SEEN OVER THE ISTHMUS AND GULF OF TEHUANTEPEC AHEAD OF A TROPICAL WAVE WITH AXIS ALONG 93W N OF 13N. $$ GR