000
AXPZ20 KNHC 310313
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE AUG 31 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...SPECIAL FEATURE...

LOW PRES 1006 MB IS CENTERED NEAR 15N105W MOVING WNW AROUND 5 
KT. S TO SW WINDS OF 20 TO 25 KT ARE OCCURRING IN THE AREA S OF 
THE LOW FROM 05N TO 15N BETWEEN 99W AND 112W WITH COMBINED SEAS 
OF 8 TO 13 FT IN SW SWELL. SCATTERED MODERATE AND ISOLATED 
STRONG CONVECTION IS OCCURRING WITHIN 240 NM IN THE W QUADRANT. 
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 
08N86W TO 13N93W THEN RESUMES FROM 10N104W TO 12N127W TO 
11N140W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 11N 
BETWEEN 114W AND 128W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS WITHIN 180 NM S AND 120 NM N OF THE AXIS BETWEEN 
128W AND 140W.

...DISCUSSION...

ALOFT...A DEEP TROUGH AXIS EXTENDS FROM SOUTHERN CALIFORNIA NEAR 
32N121W TO 27N123W. THIS TROUGH IS CREATING A WEAKNESS IN THE 
SUBTROPICAL RIDGE WHICH EXTENDS FROM AN ANTICYCLONE LOCATED OVER 
N CENTRAL MEXICO NEAR 27N104W SW ACROSS THE SOUTHERN TIP OF BAJA 
CALIFORNIA TO 20N120W. DIFFLUENT EASTERLY FLOW PREVAILS NEAR THE 
MEXICAN COAST BETWEEN THIS ANTICYCLONE AND AN INVERTED TROUGH 
EXTENDING FROM NEAR 15N100W TO 20N97W AND INTO THE SW GULF OF 
MEXICO. 

A DEVELOPING ANTICYCLONE IS POSITIONED NEAR 15N128W WITH A RIDGE 
EXTENDING NW TO 32N137W. WATER VAPOR SATELLITE IMAGERY INDICATES 
VERY DRY AIR UNDER MODERATE TO STRONG SUBSIDENCE PRESENT ACROSS 
THE AREA N OF 17N AND W OF 118W.

AT THE SURFACE...THE REMNANT LOW OF FRANK IS POSITIONED NEAR 
20N111W WITH WINDS HAVING DIMINISHED BELOW 15 KT NEAR THE 
CIRCULATION CENTER. THIS LOW IS EXPECTED TO DISSIPATE BY EARLY 
TUESDAY MORNING. A TIGHT PRESSURE GRADIENT EXISTS N OF 25N 
WITHIN 120 NM OF THE COAST OF BAJA CALIFORNIA BETWEEN THE 
SEMI-PERMANENT TROUGH OF LOW PRESSURE OVER THE GULF OF 
CALIFORNIA AND A RIDGE WHICH EXTENDS FROM 1035 MB HIGH PRESSURE 
CENTERED WELL NW OF THE AREA NEAR 42N153W TO 31N137W TO 20N117W. 
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 OVER THE NEXT FEW HOURS AS THE PRESSURE GRADIENT 
RELAXES. 

SW CONVERGENT FLOW S OF THE MONSOONAL TROUGH IS OCCURRING IN THE 
AREA FROM 07N TO 11N BETWEEN 112W AND 121W...WITH S TO SW WINDS 
OF 20 TO 25 KT AND COMBINED SEAS OF 8 TO 13 FT IN SW SWELL. 
THESE CONDITIONS ARE EXPECTED TO PERSIST DURING THE NEXT 48 
HOURS. A TIGHT PRESSURE GRADIENT WILL BECOME ESTABLISHED OVER 
THE FAR SE PORTION OF THE AREA S OF 07N BETWEEN 79W AND 88W IN 
36 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 118W. THESE SWELLS HAVE REACHED ALL THE WAY 
TO THE COAST OF U.S. SOUTHERN CALIFORNIA WITH PEAK WAVE PERIODS 
OF 14-16 SECONDS. NW SWELL GENERATED BY A LOW PRESSURE 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.

$$
HUFFMAN