000 AXPZ20 KNHC 130301 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT APR 13 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A WEAK MONSOON TROUGH AXIS EXTENDS FROM NW COLOMBIA TO 08N83W TO 05N92W TO 07N105W TO 07N119W. SCATTEROMETER AND MODEL DATA SUGGEST THAT THE ITCZ AXIS EXTENDS FROM 05N120W TO 05N130W TO 06N140W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... E OF 105W... A MID/UPPER LEVEL TROUGH HAS CONTINUED TO MIGRATE EWD OVER THE PAST 24 HRS...AND PRESENTLY EXTENDS ALONG 90W N OF 11N...AND SSW FROM THERE TO 07N93W TO 04N94W. TO ITS E...UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA WITH THE ASSOCIATED ANTICYCLONE LOCATED OVER NW COLOMBIA. AN ILL-DEFINED ELONGATED UPPER LEVEL CYCLONE IS JUST S OF THE EQUATOR AT 01S86W. MOISTURE AND INSTABILITY REMAINS VERY LIMITED WITH THE TROUGH AS IT IS IN AN ENVIRONMENT CHARACTERIZED BY MODERATE SUBSIDENCE ALOFT SUPPRESSING AREAL COVERAGE OF DEEP CONVECTION OVER THIS PORTION OF THE AREA. EARLIER SCATTERED SHOWER/TSTM THAT HAD DEVELOPED ALONG AND NEAR THE WEAK MONSOON TROUGH HAS SINCE DISSIPATED... HOWEVER DEBRIS BLOWOFF CLOUDINESS FROM THIS ACTIVITY IS BEING CHANNELED NE AND E AROUND THE WESTERN PERIPHERY OF THE PRESENT ANTICYCLONIC FLOW. THIS MOISTURE IS IN THE FORM OF SCATTERED TO BROKEN CIRRUS CLOUDS...AND IS ACROSS MOST OF CENTRAL AMERICA FROM HONDURAS TO NRN COSTA RICA. UPPER NW FLOW BEHIND THE TROUGH IS ADVECTING HIGH LEVEL DEBRIS CLOUDINESS FROM PREVIOUS ITCZ- RELATED CONVECTION EWD TO NEAR 100W WHERE IT EVAPORATES IN THE MODERATE SUBSIDENCE CONDITIONS ALOFT. THE EASTERN EXTENSION OF A JET STREAM BRANCH EXTENDS FROM 20N110W NEWD TO ACROSS CENTRAL MEXICO. MODERATE SW TO W WINDS ALONG AND WITHIN 180 NM S OF THIS JET STREAM BRANCH ARE ADVECTING SCATTERED THIN CIRRUS CLOUDS NEWD ACROSS CENTRAL MEXICO FROM ABOUT 18N TO 24N...AND NE FROM THERE TO ACROSS THE GULF OF MEXICO. LATEST SATELLITE IMAGERY SHOWS STREAMERS OF CUMULUS CLOUDS WITH POSSIBLE ISOLATED SHOWERS TO SW OF SE MEXICO...GUATEMALA...EL SALVADOR AND NICARAGUA. THE AFOREMENTIONED TROUGH WILL SHIFT E OF THE DISCUSSION AREA TONIGHT INTO SAT ALLOWING FOR MORE A ZONAL UPPER PATTERN TO BECOME ESTABLISHED ACROSS THIS PORTION OF THE AREA. W OF 105W... BROAD MID/UPPER LEVEL ANTICYCLONE FLOW IS PRESENT S OF 25N BETWEEN THE TROUGH DESCRIBED ABOVE AND 133W. AN UPPER TROUGH STRETCHES FROM A DEVELOPING UPPER LOW OVER SE ARIZONA SW ACROSS CENTRAL BAJA CALIFORNIA TO 27N129W WHERE IT BECOMES A SHEAR AXIS SW TO AN UPPER LEVEL LOW W OF THE AREA AT 23N145W. A TROUGH EXTENDS FROM THIS LOW SE TO 12N141W TO NEAR 04N131W. A NEARLY STATIONARY UPPER LEVEL ANTICYCLONE IS NW OF THE AREA AT 34N139W. A JET STREAM BRANCH ENTERS THE DISCUSSION AREA THROUGH 18N140W ...AND CONTINUES NE TO 24N128W AND TURNS SEWD TO 20N105. BOTH SATELLITE-DERIVED WINDS AND UPPER-AIR MODEL DATA INDICATE WINDS OF 60-95 KT WITH THE JET E OF 123W. THESE WINDS ARE TRANSPORTING MOSTLY BROKEN CIRRUS CLOUDS FROM THE DEEP TROPICAL CENTRAL PACIFIC REGION NEWD TO WELL INTO THE DISCUSSION AREA FROM 13N TO 21N. AT THE SURFACE...A 1030 MB HIGH CENTER IS NW OF THE AREA AT 36N141W WITH A RIDGE EXTENDING FROM IT SEWD TO 21N123W. HIGH PRES COVERS THE AREA N OF 18N AND W OF 123W. THE ASCAT PASS FROM 1730 TO 1914 UTC FRI AFTERNOON SUGGESTED THAT NW TO N WINDS OF 20-25 KT ARE CONFINED TO N OF 28N BETWEEN 119W AND 130W...WITH SEAS IN THE RANGE OF 10-15 FT DUE TO A LARGE NW SWELL TRAIN PROPAGATING INTO THE NE PART OF THE AREA. THE 1030 MB HIGH IS FORECAST TO WEAKEN SLIGHTLY OVER THE NEXT 24 HRS AS IT MOVES NNE. SEAS WILL SUBSIDE TO 9 FT IN THE AREA OF 20-25 WINDS KT BY 48 HRS. A WEAK SURFACE TROUGH IS ANALYZED ALONG 121W FROM 09N TO 12N. SCATTERED MODERATE CONVECTION IS WITHIN 45 NM OF 10N120W. LARGE LONG PERIOD S SWELLS CROSSING THE EQUATOR OVER THE SE PORTION AND NEAR THE GALAPAGOS ISLANDS ARE FORECAST TO SPREAD NWD TO NEAR 10N BETWEEN 92W AND 105W BY SAT AFTERNOON WITH RESULTANT SEAS OF 8 FT. $$ AGUIRRE