000
AXPZ20 KNHC 070256
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT AUG 07 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...

AT 07/0300 UTC...THE CENTER OF TROPICAL STORM ESTELLE WAS 
LOCATED NEAR LATITUDE 17.2 NORTH...LONGITUDE 106.2 WEST. ESTELLE 
IS MOVING TOWARD THE WEST-NORTHWEST NEAR 12 MPH...19 KM/HR...AND 
THIS GENERAL MOTION WITH A DECREASE IN FORWARD SPEED IS EXPECTED 
OVER THE NEXT COUPLE OF DAYS.  ON THIS TRACK...ESTELLE WILL 
CONTINUE TO MOVE WELL AWAY FROM THE COAST OF SOUTHWEST MEXICO. 
MAXIMUM SUSTAINED WINDS ARE NOW 45 KT WITH GUSTS TO 55 KT. SEE 
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. SCATTERED MODERATE 
WITHIN 60 NM E QUADRANT. NUMEROUS MODERATE SCATTERED STRONG 
WITHIN 75 NM S QUADRANT. ESTELLE IS EXPECTED TO REMAIN IN A LOW 
SHEAR ENVIRONMENT AND OVER WARM WATER FOR ANOTHER DAY OR 
SO...AND ADDITIONAL STRENGTHENING IS EXPECTED. AFTER 48 
HOURS...ESTELLE IS EXPECTED TO MOVE OVER COOLER WATER AND STEADY 
WEAKENING IS ANTICIPATED TO BEGIN.

...ITCZ...

ITCZ AXIS ALONG SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 91W AND 95W... 
WITHIN 120 NM N OF THE AXIS BETWEEN 92W AND 97W...WITHIN 60 NM 
EITHER SIDE OF THE AXIS BETWEEN 100W AND 118W...AND WITHIN 120 
NM EITHER SIDE OF THE AXIS BETWEEN 126W AND 135W.
 
...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE DOMINATING THE NW WATERS IS CENTERED 
NEAR 26N140W WITH AN UPPER RIDGE EXTENDING BEYOND 32N138W. A 
SECOND UPPER LEVEL ANTICYCLONIC CIRCULATION WAS LOCATED OVER NE 
TEXAS WITH AN ASSOCIATED RIDGE EXTENDING ACROSS NORTHERN MEXICO 
THEN SW ACROSS BAJA CALIFORNIA INTO THE EAST PACIFIC TO NEAR 
19N115W. TROPICAL STORM ESTELLE IS MOVING AROUND THE SOUTHERN 
PERIPHERY OF THIS RIDGE AND IS EMBEDDED WITHIN AN AREA OF UPPER 
LEVEL EASTERLY FLOW WHICH IS CONDUCIVE FOR ADDITIONAL 
STRENGTHENING.

AN UPPER LEVEL TROUGH ENTERS THE FORECAST AREA NEAR 32N120W AND 
CONTINUES SW TO A COL NEAR 22N133W. VERY DRY AIR ALOFT WITH 
MODERATE TO STRONG SUBSIDENCE IS PRESENT ACROSS THE AREA N OF 
20N AND W OF 117W. AN INVERTED TROUGH EXTENDS FROM 16N140W TO 
THE COL. EASTERLY/ZONAL FLOW PREVAILS ACROSS THE REMAINDER OF 
THE DISCUSSION AREA IN THE DEEP TROPICS S OF 10N. UPPER LEVEL 
MOISTURE RESULTING FROM ITCZ CONVECTION IS BEING ADVECTED TO THE 
WEST AS A RESULT OF THE PERSISTENT EASTERLY WINDS.

AT THE SURFACE...A RIDGE DOMINATES THE NORTHERN WATERS MAINLY N 
OF 18N. A TROUGH IS IN THE NORTHERN GULF OF CALIFORNIA AND A 
TIGHT PRES GRADIENT THERE IS PRODUCING 20 KT SE WINDS N OF 29N. 
THESE WINDS ARE EXPECTED TO PERSIST THROUGH 36 HOURS THEN WILL 
DISSIPATE THEREAFTER AS THE PRES GRADIENT RELAXES.

ANOTHER SURFACE TROUGH EXTENDS FROM 13N132W TO 08N139W. 20 KT NE
WINDS AND 8 FT SEAS ARE OCCURRING WITHIN 150 NM NW OF THE TROUGH 
AXIS N OF 11N. THESE MARINE CONDITIONS WILL PERSIST AHEAD OF THE 
TROUGH AXIS DURING THE NEXT 24-36 HOURS WITH THE TROUGH EXPECTED 
TO DISSIPATE THEREAFTER. 

CROSS EQUATORIAL SOUTHERLY SWELL WITH PERIODS OF 14-16 SECONDS 
EXISTS ACROSS THE SOUTHERN PORTION OF THE WATERS FROM 04N TO 10N 
BETWEEN 86W AND 123W WITH COMBINED SEAS OF 8-10 FT. THE LONG 
PERIOD SWELL WILL GRADUALLY DECAY DURING THE NEXT 24 TO 48 HOURS 
WHILE FRESH SW WIND SEAS ARE GENERATED DUE TO SW 20-25 KT WINDS 
WITHIN 240 NM S OF THE ITCZ MAINLY BETWEEN 100W AND 130W.

$$
LEWITSKY