000 AXPZ20 KNHC 210951 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE MAY 21 2013 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 0930 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS W AND THEN NW FROM THE COLOMBIA/PANAMA BORDER AT 08N78W ACROSS THE EXTREME SOUTHERN TIP OF PANAMA TO 10N87W TO 10N107W...THEN TURNS WSW TO 08N116W ...THEN NW TO 12N126W WHERE IT LOSES IDENTITY. SCATTEROMETER WINDS INDICATE AN ITCZ FORMS SW OF THE REMNANTS OF ALVIN AT 12N127W AND CONTINUES SW TO BEYOND 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED TO THE E OF 120W WITHIN 150 NM OF MONSOON TROUGH AXIS...AND ALSO WITHIN 75 NM OF ITCZ AXIS BETWEEN 131W AND 137W. A TROPICAL WAVE CURRENTLY IN THE EASTERN CARIBBEAN WILL REACH THE SW CARIBBEAN ON WED NIGHT. MODEL GUIDANCE IS SUGGESTING A SURFACE LOW WILL FORM ALONG THE MONSOON TROUGH AXIS NEAR 11N81W AS THE TROPICAL WAVE MOVES INTO THE MONSOON TROUGH. A SECOND LOW PRESSURE IS ALSO EXPECTED TO DEVELOP ALONG THE MONSOON TROUGH AXIS IN THE PACIFIC WATERS NEAR 10N86W WED NIGHT INTO THU...WITH THE LOW MEANDERING IN THAT AREA INTO THE WEEKEND. MODEL GUIDANCE SUGGESTS THE NORTHERLY DRAINAGE FLOW WILL INCREASE TO 20 KT IN THE GULF OF TEHUANTEPEC ON FRI NIGHT AND GRADUALLY INCREASE TO 20-25 KT ON SAT NIGHT THROUGH SUNRISE ON SUN. A SURFACE RIDGE EXTENDS FROM NW TO SE FROM 32N135W TO 20N110W. NW WINDS ARE CURRENTLY AT 10-15 KT ALONG THE ENTIRE W SHORE OF THE BAJA CALIFORNIA PENINSULA WITH SEAS OF 4-5 FT. NORTHERLY WINDS AT 15-20 KT CONTINUE ACROSS THE N-CENTRAL PACIFIC WATERS TO THE N OF 30N BETWEEN 120W-130W WITH SEAS MAXING AT 8 FT IN THE ASSOCIATED N SWELL THAT CONTINUES TO MIX WITH LONG PERIOD CROSS-EQUATORIAL SW SWELL. A REINFORCING N SURGE AT 20 TO 25 KT WILL ARRIVE ALONG 32N LATER TODAY WITH ONLY 20 KT WINDS SPREADING S ACROSS THE PACIFIC WATERS TO THE N OF 20N BETWEEN 115W-140W ON THU NIGHT...WITH SEAS BUILDING 8 TO 13 FT IN LONG PERIOD N SWELL ON WED INTO THU NEAR 30N120W. SEAS OF 6-8 FT ARE EXPECTED TO REACH ALONG THE BAJA PENINSULA TO THE N OF 28N AS EARLY AS SUNRISE ON THU...AND MAY REACH AS FAR S AS 25N NEAR BAHIA SANTA MARIA LATE THU NIGHT MOSTLY IN REFRACTIVE SWELL. WIND/SEAS WILL BEGIN TO DIMINISH/SUBSIDE ON FRI WITH WINDS 15 KT AND SEAS 5-7 FT ACROSS THE SUBTROPICAL WATERS ON SAT. THE REMNANTS OF ALVIN HAVE WEAKENED TO SW-NE ORIENTATED TROUGH THAT EXTENDS FROM 10N130W TO 15N126W. NE TO E WINDS AT 20-25 KT AND SEAS 7-10 FT ARE NOTED WITHIN 300 NM NW OF THE TROUGH. EXPECT THE SW-NE ORIENTATED TROUGH TO DRIFT W AND EXTEND FROM 09N133W TO 14N128W TONIGHT...AND FROM 09N136W TO 11N133W TO 13N128W ON WED NIGHT...ALL THE WHILE INTERRUPTING THE ITCZ. THE NE TRADES TO THE W OF THE TROUGH WILL DIMINISH TO 15-20 KT TONIGHT...WITH THE ASSOCIATED SEAS SUBSIDING TO LESS THAN 8 FT ON WED. ALOFT...A TROPICAL MOISTURE PLUME...ORIGINATING FROM THE CONVECTIVE DEBRIS MOISTURE FROM FORMER TROPICAL CYCLONE ALVIN... AND OTHER CONVECTION ALONG THE MONSOON TROUGH BETWEEN 116W- 121W...CONCENTRATES INTO A 180 NM WIDE PLUME FROM 12N119W TO 23N106W...THEN THE PLUME CONTINUES NE ACROSS CENTRAL MEXICO AND ACROSS THE W GULF OF MEXICO WHERE IT EVAPORATES WITH ONLY A SMALL AMOUNT OF THE MOISTURE INDICATED OVER SE TEXAS THIS MORNING. A SECOND TROPICAL PLUME ORIGINATES FROM ITCZ CONVECTION BETWEEN 136W-148W AND STREAMS NNE WITHIN 300 NM OF A LINE FROM 12N140W TO 32N130W...WITH PLUME THEN WIDENING AS IT SPILLS NE AND LATER E ACROSS SOUTHERN CALIFORNIA. $$ NELSON