000
AXPZ20 KNHC 302135
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON AUG 30 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURE...

LOW PRES 1008 MB IS CENTERED NEAR 13N102W MOVING NW AROUND 5 KT. 
SW TO W WINDS OF 20 TO 25 KT ARE OCCURRING IN THE AREA S OF THE 
LOW FROM 03N TO 13N BETWEEN 96W AND 115W WITH COMBINED SEAS OF 8 
TO 12 FT IN SW SWELL. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS OCCURRING WITHIN 330 NM IN THE W QUADRANT AND 
WITHIN 180 NM IN THE SE QUADRANT OF THE LOW. CONDITIONS APPEAR 
CONDUCIVE FOR SOME SLOW DEVELOPMENT OF THIS SYSTEM DURING THE 
NEXT COUPLE OF DAYS AND THERE IS A MEDIUM CHANCE OF THIS SYSTEM 
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 08N78W TO 
08N87W TO 14N93W THEN RESUMES FROM 09N102W TO 12N127W TO 
10N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE 
AXIS BETWEEN 80W AND 85W AND ALSO WITHIN 240 NM S OF THE AXIS 
BETWEEN 90W AND 94W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS WITHIN 240 NM S OF THE AXIS BETWEEN 114W AND 121W 
AND ALSO WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 123W AND 
140W.

...DISCUSSION...

ALOFT...A DEEP TROUGH EXTENDS FROM NEAR THE U.S. CALIFORNIA AND 
MEXICO BORDER NEAR 32N117W TO 28N122W THEN SHARPLY TO 20N122W. 
THIS TROUGH IS CREATING A WEAKNESS IN THE SUBTROPICAL RIDGE 
WHICH EXTENDS FROM AN ANTICYCLONE LOCATED OVER N CENTRAL MEXICO 
NEAR 26N105W SW ACROSS THE SOUTHERN TIP OF BAJA CALIFORNIA TO 
20N119W. DIFFLUENT EASTERLY FLOW PREVAILS NEAR THE MEXICAN COAST 
BETWEEN THIS ANTICYCLONE AND AN INVERTED TROUGH EXTENDING FROM 
NEAR 15N98W TO 20N97W TO 24N99W TO 27N101W. 

A DEVELOPING ANTICYCLONE IS POSITIONED NEAR 17N124W WITH A RIDGE 
EXTENDING NW TO 32N136W. WATER VAPOR SATELLITE IMAGERY INDICATES 
VERY DRY AIR UNDER MODERATE TO STRONG SUBSIDENCE PRESENT ACROSS 
THE AREA N OF 18N AND W OF 113W.

AT THE SURFACE...THE REMNANT LOW OF FRANK IS POSITIONED NEAR 
21N111W WITH WINDS HAVING DIMINISHED TO 10-15 KT NEAR THE 
CIRCULATION CENTER. THIS LOW IS EXPECTED TO FINALLY DISSIPATE 
TONIGHT. A TIGHT PRES GRADIENT EXISTS FROM 23N TO 28N BETWEEN 
BAJA CALIFORNIA AND 118W BETWEEN THE SEMI-PERMANENT TROUGH OF 
LOW PRES OVER THE GULF OF CALIFORNIA AND A RIDGE WHICH EXTENDS 
FROM 1035 MB HIGH PRES CENTERED WELL NW OF THE AREA NEAR 42N155W 
TO 31N140W TO 27N127W TO 23N114W. NW-N WINDS OF 20 KT ARE 
OCCURRING IN THIS AREA WITH SEAS TO 8 FT PRIMARILY IN NW SWELL. 
THE WINDS WILL DIMINISH AND SEAS WILL SUBSIDE LATE TONIGHT AS 
THE PRES GRADIENT RELAXES. 

SW CONVERGENT FLOW S OF THE MONSOONAL TROUGH IS OCCURRING IN THE 
AREA FROM 06N TO 11N BETWEEN 115W AND 128W...WITH S TO SW WINDS 
OF 20 TO 25 KT AND COMBINED SEAS OF 8 TO 12 FT IN SW SWELL. 
THESE CONDITIONS ARE EXPECTED TO PERSIST DURING THE NEXT 48 
HOURS. A TIGHT PRES GRADIENT WILL BECOME ESTABLISHED OVER THE 
FAR SE PORTION OF THE AREA S OF 07N BETWEEN 80W AND 88W IN 48 
HOURS...WITH S TO SW WINDS OF 20 KT AND COMBINED SEAS OF 8 TO 9 
FT IN SW SWELL.

OTHER MARINE CONCERNS...A SURGE OF CROSS-EQUATORIAL LONG PERIOD 
SOUTHERLY SWELL CONTINUES TO PROPAGATE NORTHWARD ACROSS THE 
FORECAST WATERS E OF 120W. THESE SWELLS HAVE REACHED ALL THE WAY 
TO THE COAST OF U.S. SOUTHERN CALIFORNIA WITH PEAK WAVE PERIODS 
OF 16-18 SECONDS. NW SWELL GENERATED BY A LOW PRES SYSTEM 
OFFSHORE OF THE U.S. PACIFIC NW COAST WILL PROPAGATE INTO THE NE 
PORTION OF THE AREA DURING THE NEXT FEW DAYS CONVERGING WITH THE 
SOUTHERLY SWELL RESULTING IN CONFUSED SEAS.

$$
LEWITSKY