000 AXPZ20 KNHC 241545 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON MAR 24 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS SW OFF THE COAST OF COLOMBIA AT 05.5N77W TO 04.5N80W...THEN TURNS NW TO 05N94W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ CONTINUES WSW TO 04N105W...THEN NW TO 06N116W AND SW TO BEYOND 04N140W. SCATTERED MODERATE TO STRONG CONVECTION...WITH FREQUENT LIGHTNING...IS FLARING ALONG THE MONSOON TROUGH AND THE EASTERN SEGMENT OF THE ITCZ WITHIN 90 NM EITHER SIDE OF A LINE FROM 05N77W TO 02N81W TO 06N96W TO 04.5N102W. ISOLATED MODERATE TO STRONG CONVECTION IS OBSERVED ALONG THE ITCZ WITHIN 120 NM EITHER SIDE OF A LINE FROM 01N111W TO 06N118W TO 04N134W. ...DISCUSSION... A LONG WAVE TROUGH DOMINATES THE UPPER LEVELS OF THE EASTERN N PACIFIC. AN EMBEDDED UPPER SHORT WAVE TROUGH IS MOVING THROUGH THE LONG WAVE PATTERN WITH ITS MEAN AXIS OVER THE FAR NW CORNER OF THE DISCUSSION AREA FROM 32N137W TO 24N146W. AN ASSOCIATED PRE-FRONTAL SURFACE TROUGH HAS MOVED INTO THE AREA ALONG 32N137W TO 29N141W AND IS FOLLOWED BY A SURFACE COLD FRONT EXTENDING ALONG 32N139W TO 28N145W. CONVECTION IS NOTED N OF 34N ALONG THE PRE-FRONTAL TROUGH. A 15-20 KT SW-W-NW WIND SHIFT IS NOTED ALONG THE PRE-FRONTAL TROUGH. BROKEN-OVERCAST LOW-MID LEVEL CLOUDS IS OBSERVED WITHIN 90 NM W OF BOTH THE TROUGH AND THE COLD FRONT. EXPECT THE COLD FRONT TO MERGE WITH ITS PRE-FRONTAL TROUGH ALONG A LINE FROM 32N134W TO 26N141W LATE TODAY. ALTHOUGH W-NW SURFACE WINDS ARE EXPECTED TO MAX AT 20 KT S OF 32N W OF THE FRONT... LONG PERIOD NW SWELL WILL MIX WITH LONG PERIOD SE CROSS- EQUATORIAL SWELL RESULTING IN COMBINED SEAS OF 8-15 FT ACROSS THE DISCUSSION AREA W OF THE FRONT...WITH THE HIGHEST SEAS N OF 30N. THE COLD FRONT WILL BEGIN TO WEAKEN FROM 30N132W TO 26N137W EARLY TUE...AND DISSIPATE BY EARLY WED...WITH A SURFACE RIDGE BUILDING FROM W TO E ALONG 27N W OF THE DISSIPATING FRONT. COMBINED SEAS OF 8-11 FT IN MIXED NW AND SE SWELL WILL CONTINUE W OF LINE FROM 30N122W TO 20N132W. THESE COMBINED SEAS OF 8 FT WILL ARRIVE ALONG THE PACIFIC COAST OF THE NORTHERN BAJA PENINSULA ON WED NIGHT...AND CONTINUE THROUGH FRI AFTERNOON SUBSIDE BELOW 8 FT FRI NIGHT. NOTE THAT AS THE RIDGE BUILDS FURTHER E THE GRADIENT WILL TIGHTEN AND SUPPORT NW 20-25 KT ALONG THE PACIFIC COAST OF THE BAJA CALIFORNIA PENINSULA ON THU EVENING INTO FRI MORNING. AN UPPER CYCLONE HAS DEVELOPED NEAR 33N120W WITH A SECOND UPPER SHORTWAVE TROUGH EXTENDING S TO 26N125W. AN UPPER ANTICYCLONE IS CENTERED OVER THE TROPICS AT 10N90W...WITH AN UPPER RIDGE EXTENDING N ACROSS THE EASTERN COAST OF MEXICO TO A FLAT CREST OVER THE NORTHERN GULF OF MEXICO COASTAL PLAINS. SOME UPPER MOISTURE IS NOTED OVER THE E SEMICIRCLE OF THE CYCLONE AND EXTENDS E ACROSS SOUTHERN CALIFORNIA...THE NORTHERN BAJA CALIFORNIA PENINSULA AND SOUTHERN ARIZONA AND NEW MEXICO. A BAND OF DENSE UPPER MOISTURE...THAT ORIGINATES FROM ITCZ CONVECTION IN THE CENTRAL PACIFIC...IS STREAMING ENE ACROSS DISCUSSION AREA WITHIN 270 NM EITHER SIDE OF A LINE FROM 20N140W TO 27N110W WHICH CROSSES THE SOUTHERN BAJA PENINSULA AND GULF OF CALIFORNIA...THEN TURNS NE ACROSS NORTHERN OLD MEXICO. UPPER DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THE ANTICYCLONE AT 10N90W IS ENHANCING CONVECTION AS PREVIOUSLY DESCRIBED ALONG THE MONSOON TROUGH. THE DEBRIS MOISTURE EVAPORATES NEAR THE DECAYING CLUSTERS AS THE UPPER LEVELS ARE VERY DRY UNDER THE ANTICYCLONIC ENVELOPE. ELSEWHERE AT THE SURFACE...A SURFACE RIDGE EXTENDS SE FROM 32N130W TO NEAR 12N100W. S OF THE SURFACE RIDGE THE NE TRADES ARE AT 15-20 KT ACROSS THE TROPICAL WATERS N OF THE ITCZ TO ALONG 19N...WITH SEAS 7-8 FT PRIMARILY IN NE WIND WAVE MIXING WITH BOTH LONG PERIOD NW AND CROSS EQUATORIAL SE SWELL. THIS ENHANCED AREA OF SEAS IS EXPECTED TO CONTINUE THROUGH TUE...THEN BE REINFORCED BY NW SWELL PROPAGATING SE BEHIND THE COLD FRONT FURTHER TO N AS PREVIOUSLY DESCRIBED...AND COVERING THE WATERS FROM 07-20N W OF 130W ON WED MORNING. A SURFACE RIDGE WILL BUILD E ACROSS THE AREA W OF THE FRONT INCREASING THE NE TRADES WINDS S OF THE RIDGE TO 20-25 KT/SEAS 7-10 FT ACROSS THE WATERS FROM 06-17N W OF 135W ON WED NIGHT. THE GRADIENT WILL THEN WEAKEN AS THE RIDGE BECOMES ORIENTATED NE-SW FROM A SURFACE HIGH NEAR 29N125W TO 26N140W BY EARLY FRI. SOUTHERLY FLOW NW OF THIS NE-SW RIDGE WILL INCREASE SUPPORTING 15-20 KT AGAIN ON FRI AHEAD OF THE NEXT COLD FRONT ARRIVING AT 32N140W ON FRI AFTERNOON. THE FRONT SHOULD REACH FROM 32N130W TO 26N135W LATE SAT. GULF OF PAPAGAYO GAP WINDS...NE-E WINDS THAT OCCURRED AT 20-25 KT AT SUNRISE THIS MORNING ARE QUICKLY DIMINISHING. THE GRADIENT IS ONLY EXPECTED TO SUPPORT A MAXIMUM 15-20 KT DRAINAGE FLOW TONIGHT. GUIDANCE IS SUGGESTING THE GRADIENT WILL INCREASE AGAIN THEN SUPPORTING A 20-25 KT EVENT EACH NIGHT FROM TUE NIGHT THROUGH FRI NIGHT. GULF OF TEHUANTEPEC...LIGHT 5-10 KT SW WINDS THIS AFTERNOON WILL INCREASE TO 10-15 KT BRIEFLY THIS EVENING...THEN DIMINISH AND BECOME LIGHT 5-10 KT NW-N WINDS LATE TONIGHT THROUGH LATE MORNING ON TUE. THIS PATTERN WILL REPEAT ON WED AFTERNOON THROUGH THU MORNING...AND REPEAT AGAIN THROUGH THE REMAINDER OF THIS WEEK...EXCEPT GUIDANCE SUGGESTS THE NOCTURNAL MAXIMUM NORTHERLY DRAINAGE FLOW WILL INCREASE TO 20-25 KT ON TUE NIGHT THROUGH SUNRISE ON WED BEHIND A GULF OF MEXICO COLD FRONT. $$ NELSON