000
AXPZ20 KNHC 300947
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU SEP 30 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

.AXIS ANALYZED ALONG FROM LOW PRES 1008 MB NEAR 09N115W TO 09N 
124W TO LOW PRES 1012 MB NEAR 14N133W TO 11N 140W. MODERATE 
CONVECTION IS NOTED WITHIN 90 NM EITHER SIDE OF ITCZ AXIS W OF 
134W.

...DISCUSSION...

E OF 115W...
AN AREA OF LOW PRES IS WELL DEFINED ON SATELLITE IMAGERY ALONG 
THE GUATEMALAN COAST NEAR 14N92W ALONG THE GUATEMALAN 
COAST...WHERE IT HAS BEEN FOR MOST OF THE PAST 24 HOURS. THE LOW 
FORMED IN PART DUE TO STRONG NORTHERLY GAP WINDS THROUGH THE 
GULF OF TEHUANTEPEC. WHILE THE GAP WINDS HAVE DIMINISHED FOR 
NOW...BUT A 03Z ASCAT PASS AND A 08Z SHIP OBSERVATION SHOW THE 
LOW PRES IS ENHANCING 20 TO 25 KT SW FLOW ON THE SOUTHERN 
PERIPHERY OF THE LOW...LOWER THAN WHAT THE 00Z GFS IS 
INITIALIZING. THIS FEATURE MAY MOVE INLAND TODAY AND THE MAIN 
IMPACT WILL BE RAINFALL ALONG THE GUATEMALAN COAST AND ADJACENT 
HIGHLANDS. MEANWHILE LOW PRES WILL AGAIN DEVELOP IN THE NW 
CARIBBEAN...AND TIGHTEN THE PRESSURE GRADIENT ENOUGH IN THE GULF 
OF MEXICO TO ALLOW A NEW SHOT OF GAP WIND FLOW THROUGH 
TEHUANTEPEC STARTING TONIGHT. GLOBAL MODELS ADVERTISE THIS EVENT 
TO PERSIST THROUGH THE WEEKEND AND MAY REACH 30 KT. FURTHER TO 
THE N...A PERSISTENT WEAK LOW PRES AREA WILL CONTINUE NEAR 
18N108W...WITH LITTLE SIGN OF FURTHER DEVELOPMENT. ELSEWHERE A 
BROAD BAND OF FRESH SW WINDS WILL GRADUALLY DIMINISH THROUGH 
FRI. LONG PERIOD NW AND SW SWELL PUSH INTO THE AREA INTO THE 
WEEKEND WITH COMBINED SEA HEIGHTS OF 8 TO 10 FT.

W OF 115W...
BROAD REX BLOCK PATTERN REMAINS IN PLACE IN THE MID AND UPPER 
LEVELS W OF 125W...GENERALLY DEFLECTING A SHORT WAVE TROUGH TO 
THE NORTH OF THE DISCUSSION AREA. MODEST CONVECTION IS FLARING 
ALONG THE ITCZ W OF 130W...UNDER AN AREA OF UPPER DIFFLUENCE 
BETWEEN THE MID/UPPER RIDGE TO THE NORTH AND THE MID/UPPER 
CYCLONE TO THE SOUTH. LOW PRES 1012 MB IS NOTED IN THIS AREA 
ALONG THE ITCZ NEAR 14N135W...AND IS EXPECTED TO PERSIST FOR THE 
NEXT COUPLE OF DAYS IN THIS AREA. ELSEWHERE...DECAYING 10-14 SEC 
SWELL PUSHING SE FROM THE N CENTRAL PACIFIC WITH HEIGHTS 
SUBSIDING SOME OVER THE NW PORTION OF THE AREA. A SECOND SURGE 
OF NW SWELL WILL REACH FAR NW WATERS BY LATE THU WITH SEAS 
REMAINING IN THE 8 TO 9 FT RANGE. 

$$
CHRISTENSEN