000
AXPZ20 KNHC 230936 CCA
TWDEP 

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU SEP 23 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 
0845 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N104W TO 10N140W. SCATTERED 
MODERATE CONVECTION IS NOTED WITHIN 60 NM S OF AXIS BETWEEN 112W 
AND 120W.

...DISCUSSION...

E OF 110W...A BROAD AREA OF LOW PRES IS NOTED OFF THE COAST OF 
ACAPULCO MEXICO...MOVING SLOWLY WNW. THIS FEATURE DOES NOT 
APPEAR TO BE WELL ORGANIZED ON SATELLITE IMAGERY AT THIS 
TIME...AND THE PRIMARY CIRCULATION CENTERED NEAR 15N100W IS 
LIKELY MAINLY IN THE MID LEVELS WITH WEAK TROUGHING AT THE 
SURFACE. A SMALL CLUSTER OF THUNDERSTORMS IS PULSING NEAR THE 
CENTER CURRENTLY. AN UPPER LOW CENTERED OVER THE WESTERN GULF 
OF MEXICO TO THE NORTH IS PROVIDING DRY SUBSIDENT AIR ACROSS 
THIS LOW PRES AREA...LIMITING CONVECTIVE DEVELOPMENT. AN ASCAT 
PASS FROM 16Z SHOWED A SMALL AREA OF WINDS TO 20 KT ON THE S OF 
THE TROUGH/LOW CENTER. THIS COINCIDED WITH JASON ALTIMETER PASS 
SHOWING SEAS TO 7 FT. THE GFS AND ECMWF SHOW WEAK SURFACE LOW 
DEVELOPMENT THROUGH FRI...AS THE LOW PRES DRIFTS SLOWLY WESTWARD 
TO ABOUT 110W THROUGH SAT. SEE ABPZ20 KNHC/TWOEP FOR FURTHER 
DETAILS ON THIS LOW PRESSURE AREA. ELSEWHERE MODERATE SW FLOW 
PERSISTS GENERALLY S OF 15N.  CONVECTION LIMITED TO THE AREA 
JUST OFF THE COASTS OF MEXICO AND CENTRAL AMERICA WHERE SW 
MONSOON FLOW IS CONVERGING WITH NOCTURNAL DRAINAGE FLOW.

LOOKING AHEAD...ANOTHER AREA OF LOW PRES IS DEVELOPING IN THE 
CENTRAL CARIBBEAN...AND IS EXPECTED TO MOVE INTO THE WESTERN 
CARIBBEAN TOWARD CENTRAL AMERICA THROUGH SAT. IF THIS PANS 
OUT...EXPECT THE SW FLOW TO INCREASE FROM 05N TO 10N.

W OF 110W...SURFACE LOW PRES 1012 MB IS CENTERED NEAR 
11N130W...WITH BROAD HIGH PRES TO THE NORTH. ASCAT DATA SHOW A 
SWATH OF 20 KT WINDS TO THE NORTH OF THE LOW PRES. THE LOW IS 
EXPECTED TO MOVE E AND DISSIPATE THROUGH TONIGHT...ALLOWING 
WINDS TO DIMINISH SLIGHTLY. THE SURFACE HIGH PRES EXTENDS E 
TOWARD THE BAJA PENINSULA. ASCAT AND SHIP OBSERVATIONS SHOW AN 
ENHANCED AREA OF WINDS BETWEEN THE SURFACE RIDGE AND THE BAJA 
COAST N OF 23N E OF 115W. LOOKING AHEAD...WAVEWATCH III MODEL 
SHOWS LONG PERIOD SWELL UP TO 12 FT WILL MOVE INTO THE NW 
DISCUSSION AREA THIS WEEKEND...EXTENDING FROM SOUTHERN 
CALIFORNIA TO ROUGHLY 16N140W BY LATE SUN.

$$
CHRISTENSEN