000 AXPZ20 KNHC 282155 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC TUE MON APR 28 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... AN ILL-DEFINED MONSOON TROUGH EXTENDS FROM THE COAST OF COLOMBIA AT 05N77W TO 06N96W WHERE SCATTEROMETER WINDS INDICATE AN ITCZ FORMS...AND CONTINUES W THROUGH 07N110W TO BEYOND 06N140W. ISOLATED MODERATE AND STRONG CONVECTION IS OBSERVED ACROSS COSTA RICA AND ALONG THE MONSOON TROUGH AND ITCZ WITHIN AN AREA BOUNDED FROM 03-11N BETWEEN 84-102W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE ITCZ WITHIN 180 NM EITHER SIDE OF A LINE FROM 08N118W TO 05N134W. SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 180 NM EITHER SIDE OF A LINE FROM 05N134W TO 04N140W. ...DISCUSSION... AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 07N143W WITH AN UPPER RIDGE EXTENDING NE TO WELL BEYOND 32N127W. AN UPPER TROPICAL RIDGE ALSO EXTENDS E FROM THE ANTICYCLONE ALONG 08N TO A CREST NEAR 08N134W. DRY UPPER AIR IS INDICATED WITHIN THE RIDGE AND IS SUPPRESSING CONVECTION TO THE N OF THE ITCZ... WHILE ENHANCING CONVECTION OVER AND TO S OF ITCZ ALL TO THE W OF 134W. AN UPPER CYCLONE IS CENTERED AT 21N128W WITH AN UPPER TROUGH EXTENDING S TO 11N126W...THEN SE TO A BASE OVER THE DEEP TROPICS AT 02N113W. THIS TROUGH SEPARATES THE ANTICYCLONIC UPPER OVER THE W PORTION FROM THAT ASSOCIATED WITH ANOTHER UPPER ANTICYCLONE CENTERED AT 10N103W WITH A RIDGE AMPLIFYING N TO A CREST AT 27N118W. A LARGE AREA OF UPPER DIFFLUENCE IS INDUCED TO THE E OF THE UPPER TROUGH AND SW OF THE RIDGE...AND IS ENHANCING THE CONVECTION PREVIOUSLY DESCRIBED ALONG THE ITCZ BETWEEN 118-134W. A VERY DENSE MOISTURE PLUME IS ADVECTED N AND NE ALONG THE PERIPHERY OF THE UPPER RIDGE COVERING THE DISCUSSION AREA FROM 10-23N BETWEEN 111-125W. SOME OF THIS MOISTURE TURNS E ACROSS MEXICO BETWEEN 16-24N. AN UPPER RIDGE EXTENDS E FROM THE TROPICAL ANTICYCLONE AT 10N103W TO A CREST OVER NICARAGUA. DRY AIR IS SUPPRESSING CONVECTION UNDER THE RIDGE TO THE N OF 11N...WHILE ENHANCING THE ISOLATED CONVECTION ALONG THE MONSOON TROUGH AND ITCZ BETWEEN 84-102W AS PREVIOUSLY DESCRIBED. AT THE SURFACE...A 1025 MB HIGH IS CENTERED AT 32N131W WITH A RIDGE EXTENDING SE TO A CREST LAST DEPICTED ON SCATTEROMETER WINDS AT 13N105W. NE 20-25 KT TRADES ARE OBSERVED TO THE S OF THE RIDGE FROM 09-16N BETWEEN 122-140W...WITH COMBINED SEAS OF 7-10 FT IN MIXING LONG PERIOD NW...NE AND S SWELL. THE GRADIENT WILL RELAX TONIGHT WITH NE 15-20 KT WINDS EXPECTED FROM 07N TO THE RIDGE ON TUE. THE GRADIENT IS RELAXING NE OF THE RIDGE WITH THE AREA OF NW 20-25 KT WINDS RETRACTED TO THE N OF 31N. HOWEVER A 360 NM WIDE TONGUE OF 15-20 KT WINDS CONTINUE S TO 19N113W. THESE NW WINDS CURRENTLY EXTEND TO THE PACIFIC COAST OF THE BAJA PENINSULA TO THE N OF ISLAS CEDORAS. THE GRADIENT WILL GRADUALLY RELAX WITH WINDS LESS THAN 20 KT ON TUE NIGHT...AND THE SEAS WILL SUBSIDE BELOW 8 FT ON WED. A SMALL AREA OF MIXING LONG PERIOD NW...SE AND SW SWELL IS RESULTING IN SEAS 7-9 FT ACROSS THE TROPICAL WATERS S OF A LINE FROM 00N120W TO 02N112W TO 3.4S105W. THIS SWELL WILL GRADUALLY DECAY TO LESS THAN 8 FT ON TUE NIGHT. A SURFACE COLD FRONT WILL ENTER THE NW PORTION ON WED ACCOMPANIED BY A SW-W-NW 15-20 KT WINDS ACROSS THE WATERS S OF 32N WITH SEAS OF 7-9 FT. THE FRONT WILL SLOW AND WASH OUT ALONG 32N132W TO 25N138W ON WED. GULF OF CALIFORNIA...NW WINDS WILL INCREASE TO 15 KT ACROSS THE GULF WATERS N OF 30N EARLY TONIGHT...THEN RAPIDLY INCREASE TO 20- 30 KT ACROSS THE GULF TO THE N OF 27N ON TUE. THE GRADIENT WILL SUPPORT 20-25 KT ON WED...THEN RELAX THROUGH THU WITH WINDS BELOW 20 KT ON THU NIGHT. GULF OF TEHUANTEPEC...THE NOCTURNAL DRAINAGE WILL MAX AT 15 KT TONIGHT AND TUE NIGHT...THEN INCREASE TO A 20 KT MAX ON WED NIGHT AND THU NIGHT. GUIDANCE IS SUGGESTING A 20-25 KT EVENT ON FRI NIGHT THROUGH SUNRISE ON SAT. $$ NELSON