000 AXPZ20 KNHC 142155 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI NOV 14 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...SPECIAL FEATURES... ...GULF OF TEHUANTEPEC GALE WARNING... A VERY TIGHT SURFACE PRESSURE GRADIENT HAS DEVELOPED BETWEEN A 1033 MB HIGH PRESSURE CENTER THAT IS IN ARKANSAS...AND A STATIONARY FRONT THAT HAS REACHED THE ISTHMUS OF TEHUANTEPEC OF SOUTHERN MEXICO. COLD DENSE AIR THAT MOVED ACROSS THE U.S.A. INTO MEXICO BEHIND THE COLD FRONT...AND IT MIXED DOWNWARD TO THE SEA SURFACE WHERE WARM TEMPERATURES HAVE BEEN OBSERVED. THE RESULTANT NORTH-TO-NORTHEAST GALE-FORCE WINDS BEGAN LAST NIGHT IN THE RANGE OF 30 TO 40 KNOTS. AN 1100 UTC OBSERVATION FROM A SHIP WITH CALL SIGN "VRED4" REPORTED NORTHEAST 35 KNOT WINDS AT LOCATION OF 14N96W. A PARTIAL ASCAT-B PASS FROM NEAR 1532 UTC TODAY INDICATED 30 TO 40 KNOT NORTHERLY WINDS IN THE CENTRAL PART OF THE GULF OF TEHUANTEPEC. THE SEA HEIGHTS IN THE GULF OF TEHUANTEPEC HAVE BUILT UP TO THE RANGE OF 11 TO 18 FEET. THIS REMAINS IN LINE WITH THE LATEST TAFB-NWPS MODEL OUTPUT FOR THE AREA. THE GALE-FORCE WINDS WILL CONTINUE THROUGH EARLY SATURDAY BEFORE SUBSIDING TO JUST LESS THAN GALE FORCE BY EARLY IN THE AFTERNOON. THE WIND SPEEDS WILL CONTINUE TO DIMINISH TO 20 KNOTS OR LESS ON SATURDAY NIGHT...WHILE RESIDUAL NORTHEAST SWELLS PROPAGATE SOUTHWEST-TO-WEST WITH 8 TO 9 FOOT SEA HEIGHTS COVERING THE WATERS FROM 06N TO 12N BETWEEN 100W AND 108W BY THEN. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 09N84W TO 05N96W TO 10N112W TO 08N123W. ITCZ EXTENDS FROM 08N123W TO 10N130W TO LOW PRES NEAR 09N133W 1011 MB TO 07N140W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 06N TO 11N BETWEEN 130W AND 134W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 03N TO 14N FROM 110W EASTWARD...AND FROM 05N TO 12N BETWEEN 110W AND 125W. ...DISCUSSION... A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N120W TO 23N123W TO 17N134W. A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 24N116W 16N118W 12N119W. WATER VAPOR IMAGERY SHOWS MAINLY DRY AND STABLE AIR ACROSS THE EASTERN PACIFIC OCEAN. THE EXCEPTION IS THE BASE OF THE 24N116W 12N119W TROUGH...WITH CLOUDS AND CONVECTIVE PRECIPITATION RELATED TO THE MONSOON TROUGH/ITCZ. A 1011 MB LOW PRESSURE CENTER IS NEAR 09N133. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 06N TO 11N BETWEEN 130W AND 134W. EXTENSIVE MIDDLE LEVEL TO UPPER LEVEL MOISTURE...IN THE FORM OF MOSTLY BROKEN CIRRUS CLOUDS...IS STREAMING EASTWARD...ACROSS THE NORTHWESTERN SECTION OF THE AREA. THIS MOISTURE IS AHEAD OF A LARGE TROUGH THAT IS WELL TO THE WEST OF THE AREA. SURFACE ANTICYCLONIC WIND FLOW COVERS THE EASTERN PACIFIC OCEAN FROM 22N NORTHWARD FROM 140W EASTWARD. A 1021 MB HIGH PRESSURE CENTER IS NEAR 29N127W. A SURFACE TROUGH IS ALONG 19N126W 15N122W. RAINSHOWERS ARE POSSIBLE WITHIN 120 NM ON EITHER SIDE OF THE TROUGH. THE PRESSURE GRADIENT THAT EXISTS BETWEEN THE TROUGH AND THE 1021 MB HIGH CENTER WILL RESULT IN AN AREA OF MAINLY FRESH EASTERLY WINDS NEAR THE NORTHERN END OF THE TROUGH THROUGH TONIGHT. LONG PERIOD NORTHWEST SWELL...WITH A LEADING EDGE PERIOD OF 17 TO 18 SECONDS...CONTINUES TO PROPAGATE ACROSS MUCH OF THE FORECAST WATERS THAT ARE TO THE WEST OF 110W. THE SEA HEIGHTS RANGE FROM 8 TO 10 FEET TO THE WEST OF A LINE FROM 32N115W TO 18N121W TO 05N104W PRIMARILY IN NORTHWEST LONG PERIOD SWELL. THE SWELL ENERGY IS FORECAST BY WAVEWATCH GUIDANCE TO DISSIPATE GRADUALLY DURING THE NEXT 48 HOURS. THIS WILL ALLOW FOR THE 8 TO 12 FOOT SEA HEIGHTS TO LOWER TO 9 FEET TO THE WEST OF A LINE FROM 32N137W TO 28N140W BY EARLY SUNDAY...AND TO 8 FEET IN MIXED SOUTHEAST AND NORTHWEST SWELL WITHIN AN AREA BOUNDED BY A LINE FROM 27N132W TO 19N129W TO 12N137W TO 17N136W TO 27N132W UNDER WINDS OF 20 KT OR LESS. A NEW REINFORCING SET OF NORTHWEST SWELLS IS FORECAST BY THE GUIDANCE TO ARRIVE IN THE NORTHWEST CORNER BY LATE TONIGHT AHEAD OF AN APPROACHING FRONTAL SYSTEM THAT WILL STALL OUT NEAR 32N142W ON SATURDAY. THE SEA HEIGHTS THAT WILL BE PRODUCED BY THESE SWELLS ARE EXPECTED TO REACH 8 TO 10 FEET ON SATURDAY...AND CHANGE LITTLE THROUGH SUNDAY. SOUTHERLY WIND FLOW THAT WILL BE TO THE EAST OF THE FRONTAL SYSTEM IS FORECAST TO INCREASE TO 20 TO 25 KNOTS ON SUNDAY. THE GULF OF PAPAGAYO...THE PRESSURE GRADIENT WILL STRENGTHEN ACROSS THE WESTERN CARIBBEAN DURING THE WEEKEND SUPPORTING NE WINDS OF 20 TO 25 KNOTS ACROSS THE GULF OF PAPAGAYO COMMENCING EARLY SATURDAY MORNING. THESE WINDS ARE FORECAST TO EXPAND WSW FROM THE GULF TO NEAR 90W EARLY SAT...AND TO NEAR 91W BY EARLY SATURDAY AFTERNOON WITH SEAS TO 9 OR 10 FEET. THE WINDS WILL DIMINISH TO 15 TO 20 KNOTS BY 30 TO 36 HOURS WITH SEAS TO 8 FEET IN NE SWELL...AND TO LESS THAN 8 FEET BY EARLY ON SUNDAY. LOOKING AHEAD...A STRONG LOW PRESSURE SYSTEM...THAT IS ASSOCIATED WITH THE FRONTAL SYSTEM AND LONG PERIOD SWELL FOR THE NORTHWESTERN CORNER OF THE FORECAST AREA...WILL BRING AN INCREASE IN WINDS AND SEA HEIGHTS ACROSS THE NORTHWEST WATERS BEGINNING ON SUNDAY NIGHT AND INTO MONDAY. MODEL GUIDANCE SUGGESTS WINDS OF 20 TO 30 KNOTS JUST AHEAD AND BEHIND THE FRONT WITH SEA HEIGHTS BUILDING TO 9 TO 14 FEET BY EARLY MONDAY. EXPECT INCREASING NORTHWEST WINDS OF 20 TO 25 KNOTS IN THE FAR NORTHERN GULF OF CALIFORNIA LATE ON SUNDAY INTO MONDAY WITH SEAS BUILDING TO 8 FEET AS A TIGHT PRES GRADIENT DEVELOPS THERE. $$ MT