000 AXPZ20 KNHC 122208 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI APR 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A WEAK MONSOON TROUGH AXIS EXTENDS SRN PANAMA TO 09N79W TO 06N90W TO 03N95W. SCATTEROMETER AND MODEL SUGGEST THAT THE ITCZ AXIS EXTENDS FROM 03N95W TO 06N110W WHERE IT ENDS. IT RESUMES AT 05N119W TO BELOW THE EQUATOR AT 135W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... E OF 110W... 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 THATR HAD DEVELOPED ALONG AND NEAR THE WEAK MONSOON TROUGH HAS SINCE DISSIPATED...HOWEVER DEBRIS BLOWOFF CLOUDINESS FROM THE 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 VISIBLE IMAGERY SHOWS SMALL CUMULUS CLOUDS WITH POSSIBLE ISOLATED SHOWERS S OF ABOUT 14N. 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 110W... BROAD MID/UPPER LEVEL ANTICYCLONE FLOW IS PRESENT S OF 25N BETWEEN THE TROUGH MENTIONED IN ABOVE PARAGRAPH AND 133W. AN UPPER TROUGH STRETCHES FROM AN UPPER LEVEL LOW OVER SW NEVADA SWWD ACROSS NRN BAJA CALIFORNIA AND TO 27N129W WHERE IT BECOMES A SHEAR AXIS WSW TO AN UPPER LEVEL LOW W OF THE AREA AT 23N145W. A TROUGH EXTENDS FROM THIS LOW SE TO 12N141W TO NEAR 04N134W. AN UPPER LEVEL ANTICYCLONE IS NW OF THE AREA AT 34N139W...AND IS MOVING ESE. 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 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 JUST NW OF THE AREA AT 35N141W WITH A RIDGE EXTENDING FROM IT SEWD TO 21N121W. HIGH PRES COVERS THE AREA N OF 15N AND W OF 117W. THE ASCAT PASS FROM 1730 TO 1914 UTC THIS 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 NE. SEAS WILL SUBSIDE TO 9 FT IN THE AREA OF 20-25 KT BY 48 HRS. 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 107W BY SAT AFTERNOON WITH RESULTANT SEAS OF 8 FT. $$ AGUIRRE