000 AXPZ20 KNHC 260949 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU SEP 26 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 FROM 10N85W TO 09N90W. IT RESUMES FROM LOW PRES NEAR 16N101W 1008 MB TO 13N112W TO LOW PRES NEAR 14N122W 1010 MB TO 11N127W. ITCZ AXIS THEN EXTENDS FROM 11N127W TO 10N134W TO 10N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF TROUGH E OF 86W...FROM 11N-14N BETWEEN 114W-117W...AND WITHIN 120 NM S OF TROUGH BETWEEN 119W-122W. SIMILAR ACTIVITY IS WITHIN 120 NM S OF THE ITCZ AXIS BETWEEN 130W-136W. ...DISCUSSION... SATELLITE WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL ANTICYCLONE LOCATED NEAR SOUTHERN BAJA CALIFORNIA AT 24N110W WITH RIDGING COVERING MOST OF THE CENTRAL PORTION OF THE WATERS. THE INFLUENCE OF THIS FEATURE ON THE AREA IS OBSERVED AS MODERATE TO STRONG SUBSIDENCE RESULTING IN DRY AND STABLE CONDITIONS N OF 20N E OF 128W...AND N OF 14N W OF 128W. TO THE SW OF THE ANTICYCLONE AN INVERTED SHORTWAVE UPPER LEVEL TROUGH EXTENDS FROM NEAR 20N128W TO 12N132W...AND WHILE A SHORTWAVE TROUGH LIFTING NE AROUND THE WESTERN PERIPHERY OF THE RIDGE FROM 24N124W TO 21N119W. ISOLATED SHOWERS AND TSTMS ARE WITHIN ABOUT 240 NM SE OF THE INVERTED SHORTWAVE TROUGH. TO THE E OF THE TROUGH AND SE OF THE ANTICYCLONE...FAIRLY DEEP LAYERED EASTERLY FLOW IS NOTED. THIS FLOW PATTERN CONTINUES TO ADVECT UPPER LEVEL DEBRIS MOISTURE FROM CONVECTION ALONG THE COAST OF SOUTHERN MEXICO...AS WELL AS FROM CONVECTION OVER SOUTHEASTERN MEXICO AND FROM THAT OVER THE FAR EASTERN PORTION OF THE AREA AS DESCRIBED ABOVE UNDER ITCZ/MONSOON TROUGH. OVER THE WESTERN PORTION OF THE AREA MID/UPPER LEVEL RIDGING IS PRESENT TO THE W OF 130W IN ASSOCIATION WITH AN ANTICYCLONE NEAR 12N139W. THE MEAN RIDGE AXIS STRETCHES FROM THE ANTICYCLONE NNW TO NW OF THE DISCUSSION AREA THROUGH 32N141W. DEEP LAYER MOISTURE...IN THE FORM OF BROKEN TO OVERCAST MULTILAYERED CLOUDS...COVERS THE SECTOR TO THE S OF 15N W OF 129W. THE RIDGING IS MAINTAINING VENTILATION OVER THE ITCZ RELATED CONVECTION DESCRIBED ABOVE. A SHARPENING UPPER LEVEL TROUGH EXTENDS FROM THE PACIFIC NW REGION SW THROUGH 32N126W...WHERE IT NARROWS SSW TO 20N128W. WITH DRY AND STABLE CONDITIONS ACROSS THIS PORTION OF THE AREA NO CONVECTIVE ACTIVITY IS OCCURRING WITH THIS TROUGH. ONLY PATCHES OF COOL AIR STRATOCUMULUS CLOUDS WITH POSSIBLE ISOLATED SHOWERS MOVING SSW ARE SEEN TO THE N OF 20N AND W OF 120W. THE UPPER TROUGH WILL MOVE WELL INLAND THE WESTERN U.S. DURING TODAY AS THE AREA OF MID/UPPER RIDGING OVER THE WESTERN PORTION SHIFTS EASTWARD IN ITS WAKE. AT THE SURFACE...A NEARLY STATIONARY 1031 MB HIGH PRES IS WELL NW OF THE DISCUSSION AREA NEAR 39N147W WITH A RIDGE STRETCHING SE THROUGH 32N130W TO 28N122W. A WEAK TROUGH EXTENDS JUST SE OF THE RIDGE FROM NEAR 26N116W TO 24N119W. A RATHER ILL-DEFINED SWIRL OF SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING NE TOWARDS CENTRAL BAJA CALIFORNIA IS NOTED FROM 24N-26N BETWEEN 115W-118W. THE TIGHT PRES GRADIENT BETWEEN THE RIDGE AND TROUGH IS RESULTING IN NW TO N GALE FORCE WINDS OF 25-35 KT JUST N OF THE NE PART OF THE AREA WITH SEAS THERE OF 10-13 FT. THESE WINDS ARE FORECAST TO GRADUALLY DIMINISH THROUGH THU...HOWEVER...THE THE RESULTANT SWELLS WITH PERIODS OF 15-18 SECONDS WILL PROPAGATE SEWD THROUGH MUCH OF THE NE AND N CENTRAL SECTIONS OF THE AREA THROUGH THE NEXT 24-36 HOURS...PRODUCING SEAS OF 10-12 FT TODAY TO THE N OF 28N BETWEEN 119W-124W WHERE N-NE 20-25 KT WINDS ARE PRESENT. THE SURROUNDING AREA OF SEAS OF 8-10 FT IN NW SWELLS UNDER 20 KT OR LESS WINDS IS WITHIN AN AREA BOUNDED BY A LINE FROM 30N117W TO 23N117W TO 18N120W TO 20N133W TO 30N140W TO 30N117W. THE NW SWELLS WILL CONTINUE TO SEEP TO THE SE-S THROUGH FRI AS THEY GRADUALLY DECAY. 1006 MB LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 16N101W MOVING WNW AT 10 KT. THIS LOW IS UNDERNEATH AN AREA OF UPPER EASTERLY SHEAR AS REFERENCED ABOVE WITH ASSOCIATED CONVECTION REMAINING RATHER LIMITED...AND DISPLACED NW THROUGH N OF THE LOW. THIS CONVECTION IS DESCRIBED AS OF THE SCATTERED MODERATE/ISOLATED STRONG TYPE WITHIN 150 NM OF THE LOW IN THE NE QUADRANT...ALSO FROM 16N TO 18N BETWEEN 101W-105W...AND FROM 18N TO 22N BETWEEN 106W AND 107W. ASSOCIATED WINDS ARE MODERATE TO FRESH WITH SEAS CURRENTLY LESS THAN 8 FT...HOWEVER WINDS MAY GUSTY IN THE CONVECTION. THE LOW IS FORECAST TO MOVE TO THE W-NW DURING THE NEXT 48 HOURS JUST S OF THE COAST OF MEXICO WITH DEVELOPMENT POTENTIAL AT A LOW LEVEL. ADDITIONAL HEAVY RAINS MAY SPREAD OVER AREAS OF SW MEXICO THAT ARE ALREADY WELL SATURATED DUE TO PREVIOUS TROPICAL SYSTEMS... WITH THE RISK OF FLASH FLOODING AND MUDSLIDES PARTICULARLY ACROSS PORTIONS OF SOUTHWESTERN MEXICO THROUGH THE END OF THE WEEK. 1008 MB LOW PRES IS WELL TO THE W...ALSO EMBEDDED IN THE MONSOON TROUGH...NEAR 15N122W. REMNANT 8 FT SEAS ARE OCCURRING WITHIN 120 NM OF THE LOW CENTER...INDUCED BY EARLIER FRESH TO STRONG WINDS AS WELL AS LONG PERIOD NW SWELLS SPREADING ACROSS A GREAT MAJORITY OF THE AREA. THE LOW IS FORECAST TO MOVE EASTWARD WHILE GRADUALLY DISSIPATING THROUGH THE NEXT 24 HOURS. CROSS-EQUATORIAL SE SWELLS CONTINUE TO IMPACT THE FAR SW WATERS WITH 8-9 FT SEAS S OF A LINE FROM 12N140W TO 06N116W TO 00N110W TO 00N109W. THESE SWELLS ARE FORECAST BY WAVEWATCH GUIDANCE TO GRADUALLY DECREASE IN AREAL COVERAGE THROUGH FRI. $$ AGUIRRE