000
AXPZ20 KNHC 312120
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE AUG 31 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 1007 MB IS CENTERED NEAR 16N106W MOVING WNW AROUND 5 
KT. E TO SE WINDS OF 20 KT AND COMBINED SEAS TO 9 FT IN S TO SW 
SWELL ARE OCCURRING WITHIN 210 NM IN THE NE QUADRANT OF THE LOW 
CENTER. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
WITHIN 180 NM IN THE W AND NW QUADRANTS OF THE LOW CENTER. UPPER 
LEVEL WINDS COULD DIMINISH OVER THE NEXT COUPLE OF DAYS AND 
BECOME MORE CONDUCIVE FOR DEVELOPMENT AND THUS 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 08N82W TO 
07N88W TO 10N98W THEN RESUMES AT 12N110W TO 10N140W. SCATTERED 
MODERATE AND ISOLATED STRONG CONVECTION IS FROM 05N TO 09N E OF 
88W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM S OF THE 
AXIS BETWEEN 92W AND 98W...AND ALSO WITHIN 180 NM N OF THE AXIS 
BETWEEN 95W TO 98W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS FROM 10N TO 16N BETWEEN 110W AND 116W...AND ALSO 
WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 126W AND 133W.

...DISCUSSION...

ALOFT...A MID TO UPPER LEVEL TROUGH EXTENDS FROM NEAR POINT 
CONCEPTION CALIFORNIA THROUGH 32N132W TO NEAR 22N130W. AN
ANTICYCLONE IS POSITIONED JUST W OF THE AREA NEAR 14N141W WITH 
AN UPPER RIDGE EXTENDING TO A COL NEAR 20N127W. SW FLOW EXTENDS 
FROM THE NORTHERN PERIPHERY OF THE ANTICYCLONE TO THE ABOVE 
MENTIONED TROUGH. WATER VAPOR SATELLITE IMAGERY INDICATES VERY 
DRY AIR UNDER MODERATE TO STRONG SUBSIDENCE ACROSS THE AREA N OF 
17N AND W OF 118W. CONVECTION IS BEING ENHANCED UNDER DIFFLUENT 
FLOW ON THE SE PERIPHERY OF THE RIDGE ALONG THE ITCZ W OF 126W.

ANOTHER ANTICYCLONE IS CENTERED OVER CENTRAL TEXAS WITH A RIDGE 
EXTENDING ACROSS NORTHERN MEXICO TO SOUTHERN BAJA CALIFORNIA TO 
NEAR 20N126W. AN INVERTED TROUGH HAS INTRUDED ON THE SOUTHERN 
SIDE OF THE RIDGE EXTENDING FROM 18N103W TO TO 27N101W. MAINLY 
ZONAL/NE TO E FLOW COVERS THE AREA SE OF A LINE FROM THE 
SOUTHERN TIP OF BAJA CALIFORNIA TO 12N126W WITH ABUNDANT DEEP 
LAYER TROPICAL MOISTURE OVER THE SE HALF OF THE DISCUSSION AREA.

AT THE SURFACE...A 1010 MB LOW...THE REMNANT OF FRANK...IS 
POSITIONED NEAR 20N111W. WINDS ARE ONLY 10 TO 15 KT NEAR THE 
CIRCULATION CENTER AS CAPTURED BY 1356 UTC WINDSAT AND 1648 UTC 
ASCAT PASSES. THIS LOW IS EXPECTED TO DISSIPATE TONIGHT. 1034 MB 
HIGH PRES IS CENTERED WELL NW OF THE AREA NEAR 39N150W WITH A 
RIDGE AXIS EXTENDING INTO THE AREA NEAR 32N140W AND CONTINUING 
THROUGH 26N130W TO 20N117W. NE TO E WINDS OF 10 TO 15 KT AND 
SEAS OF 4 TO 7 FT DOMINATE THE AREA N OF THE ITCZ AND W OF 110W 
UNDER THE RIDGE.

SW CONVERGENT FLOW S OF THE MONSOONAL TROUGH IS OCCURRING IN THE 
AREA FROM 07N TO 15N BETWEEN 100W AND 115W...AND ALSO S OF 07N E 
OF 87W...WITH SW TO W WINDS 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 OVER THE SAME GENERAL AREA.

OTHER MARINE CONCERNS...A SURGE OF CROSS-EQUATORIAL LONG PERIOD 
SOUTHERLY SWELL CONTINUES TO PROPAGATE NORTHWARD ACROSS THE 
FORECAST WATERS PRIMARILY E OF 126W. THESE SWELLS HAVE REACHED 
ALL THE WAY TO THE U.S. WEST COAST WITH PEAK WAVE PERIODS OF 15 
TO 17 SECONDS. THIS SWELL WILL START TO SIGNIFICANTLY SUBSIDE 
AROUND 48 HOURS.

$$
LEWITSKY