000 AXPZ20 KNHC 280925 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE MAY 28 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 0900 UTC. ...SPECIAL FEATURE... A 1005 MB LOW PRES EMBEDDED WITHIN THE MONSOON TROUGH IS LOCATED NEAR 13N96W...OR ABOUT 190 MILES SOUTH OF SALINA CRUZ MEXICO DRIFTING N. THIS SYSTEM IS GRADUALLY BECOMING BETTER DEFINED. SATELLITE IMAGES INDICATE THAT THUNDERSTORM ACTIVITY HAS BEEN REDEVELOPING NEAR THE CENTER DURING THE PAST FEW HOURS WITH A BAND OF MODERATE TO ISOLATED STRONG CONVECTION WITHIN 90 NM NW SEMICIRCLE OF LOW CENTER. MORE TSTMS ARE ALSO DEVELOPING ON THE EAST SIDE OF THIS FEATURE. IF THIS TREND CONTINUES...A TROPICAL DEPRESSION OR A TROPICAL STORM COULD OCCUR TODAY. THE MAJORITY OF THE COMPUTER MODELS MOVE THIS SYSTEM TOWARDS THE GULF OF TEHUANTEPEC IN ABOUT 36-48 HOURS. THERE REMAINS A HIGH PROBABILITY OF TROPICAL CYCLONE FORMATION WITH THIS SYSTEM DURING THE NEXT 48 HOURS AS IT MOVES TOWARDS THE COAST OF SOUTHERN MEXICO. REGARDLESS OF DEVELOPMENT...HEAVY RAINS ARE LIKELY OVER PORTIONS OF SOUTHERN MEXICO AND WESTERN CENTRAL AMERICA THROUGH THE NEXT 48 HOURS DUE TO THE PERSISTENTLY STRONG ONSHORE FLOW MEETING THE ELEVATED TERRAIN. THESE RAINS COULD PRODUCE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. SEE LATEST TROPICAL WEATHER OUTLOOK FOR MORE INFORMATION. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 08N78W TO 10N86W TO LOW PRES NEAR 13N96W 1005 MB TO 14N102W TO LOW PRES NEAR 10.5N113.5W 1009 MB TO 10N127W THEN ITCZ AXIS TO 06N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 90 NM S OF TROUGH BETWEEN 81W AND 94W...WITHIN 75 NM N OF THE AXIS BETWEEN 86W AND 88W AND FROM 11N TO 13N BETWEEN 104 AND 110W. ...DISCUSSION... ALOFT...AN UPPER TROUGH EXTENDS FROM NORTHERN BAJA CALIFORNIA TO 26N130W TO 27N140W TO AN UPPER LOW W OF THE AREA AT 19N148W. SWLY FLOW AHEAD OF THE TROUGH CONTINUES TO ADVECT DEEP TROPICAL MOISTURE FROM THE CENTRAL PACIFIC NEWD TO ACROSS THE FAR WRN PORTIONS...THEN THINS OUT AS IT SPREADS NEWD ACROSS NRN BAJA CALIFORNIA INTO THE SW CONUS. SOUTH OF THE TROUGH...BROAD ANTICYCLONIC FLOW COVERS THE AREA BETWEEN THE PACIFIC COAST OF MEXICO AND 140W...WITH A COUPLE OF ANTICYCLONES...ONE NEAR 15N128W AND THE OTHER NEAR 18N108W. AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO HAS ITS BASE OVER THE ISTHMUS OF TEHUANTEPEC. ANTICYCLONIC FLOW DOMINATES CENTRAL AMERICA AND THE REMAINDER OF THE FORECAST AREA. UPPER DIFFLUENCE ASSOCIATED WITH THIS RIDGE IS HELPING TO INDUCE CONVECTION IN THE VICINITY OF THE LOW PRES LOCATED NEAR 13N96W AS WELL AS ALL THE SCATTERED MODERATE TO ISOLATED STRONG CONVECTION SEEN ON SATELLITE IMAGERY N OF 08N BETWEEN 91W AND 100W. FARTHER WEST...A 1009 MB LOW PRES IS ALSO EMBEDDED WITHIN THE MONSOON TROUGH NEAR 10.5N113.5W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 45 NM TO 180 NM W AND NW QUADRANTS OF LOW. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS ALSO NOTED MAINLY W OF THE LOW FROM 07N TO 11N BETWEEN 114W AND 120W. THIS LOW HAS A LOW CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT 48 HOURS AS IT IS FORECAST TO REMAIN WEAK. ELSEWHERE AT THE SURFACE...A 1029 MB HIGH PRES LOCATED JUST N OF 30N140W EXTENDS A RIDGE SEWD ACROSS THE FORECAST WATERS TO NEAR 20N116W. SCATTEROMETER DATA PROVIDED OBSERVATIONS OF MODERATE TO FRESH TRADE WINDS BETWEEN THE SRN PERIPHERY OF THE RIDGE AND THE ITCZ...COVERING THE AREA FROM 10N TO 16N W OF 130W. DUE TO A TIGHT PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES OVER NW MEXICO...NW TO N WINDS HAVE INCREASED TO 20-25 KT OVER THE NE PART OF THE FORECAST REGION N OF ABOUT 24 AND E OF 123W WITH SEAS THERE IN THE 8-10 FT RANGE. EXPECT THESE MARINE CONDITIONS TO PERSIST OVER THESE WATER FOR THE NEXT 48 HOURS. THE 0408 UTC HIGH RESOLUTION ASCAT PASS SHOWED WINDS OF 20-25 KT IN ASSOCIATION WITH THE LOW PRES NEAR 13N96W. LONG PERIOD CROSS EQUATORIAL SW SWELLS AT 14-16 SECONDS DOMINATE MOST OF THE FORECAST WATERS E OF 115W. THESE SWELLS ARE MERGING WITH NW TO N SWELLS THAT COVER THE REMAINDER OF THE FORECAST WATERS. WAVEWATCH GUIDANCE SUGGESTS THAT THESE SWELLS WILL SLOWLY SUBSIDE TODAY...EXCEPT FOR THE NE PORTION OF THE AREA WHERE A NEW SET OF NW SWELLS IS ALREADY IMPACTING THAT REGION. $$ GR