000
AXPZ20 KNHC 090309
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON AUG 09 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 09/0300 UTC...THE CENTER OF TROPICAL STORM ESTELLE WAS 
LOCATED NEAR 17.8N 111.7W MOVING TOWARD THE WEST OR 270 DEGREES 
AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. MAXIMUM 
SUSTAINED WINDS REMAIN AT 40 KT WITH GUSTS TO 50 KT. ESTELLE'S 
TREK OVER COOLER WATERS AND ENTRAINMENT OF DRY AIR HAS ALLOWED 
ONLY A TEMPORARY BURST OF DEEP CONVECTION WITH THE LOW-LEVEL 
CIRCULATION PARTIALLY EXPOSED SOUTHEAST OF THE DEEP CONVECTION. 
FURTHER WEAKENING IS EXPECTED AND ESTELLE IS FORECAST TO BECOME 
A TROPICAL DEPRESSION WITHIN THE NEXT DAY. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/ WTPZ22 KNHC 
FOR MORE DETAILS.

...TROPICAL WAVE...

THE SOUTHERN EXTENT OF A TROPICAL WAVE IS N OF 13N ALONG 95W. 
SCATTERED MODERATE TO STRONG CONVECTION IS NOTED WITHIN 180 NM E 
OF THE WAVE WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION 
NOTED WITHIN 120 NM W OF THE WAVE. VARIOUS MODEL SOLUTIONS TRY 
TO DEVELOP AN AREA OF LOW PRES ALONG THIS WAVE DURING THE NEXT 
FEW DAYS ALTHOUGH ANY DEVELOPMENT SHOULD BE SLOW TO OCCUR DUE TO 
STRONG UPPER-LEVEL WINDS. THEREFORE THERE IS A LOW CHANCE OF 
THIS SYSTEM BECOMING A TROPICAL CYCLONE WHILE IT MOVES LITTLE 
DURING THE NEXT 48 HOURS.

...ITCZ...

THE ITCZ AXIS IS ALONG 12N86W TO 15N94W TO 15N97W TO 13N110W TO 
12N120W TO 11N135W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS WITHIN 150 NM S OF THE AXIS BETWEEN 105W AND 
110W...WITHIN 60 NM N OF THE AXIS BETWEEN 106W AND 110W...WITHIN 
60 NM OF THE AXIS BETWEEN 110W AND 117W...AND ALSO BETWEEN 120W 
AND 124W.
 
...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE IS LOCATED NEAR 17N133W WITH AN UPPER 
RIDGE EXTENDING N TO 32N133W. THIS ANTICYCLONE HAS MERGED WITH 
ANOTHER ANTICYCLONE THAT HAD BEEN LOCATED OVER THE FAR NW WATERS 
FOR SEVERAL DAYS. VERY DRY AIR UNDER MODERATE TO STRONG 
SUBSIDENCE IS PRESENT ACROSS THE AREA N OF THE ITCZ AND W OF 
117W.
 
A SHARP UPPER LEVEL TROUGH ENTERS THE FORECAST AREA NEAR 32N120W 
AND CONTINUES ALMOST DUE S TO NEAR 16N121W. THE AREA OF 
TROUGHINESS SEPARATES THE UPPER ANTICYCLONE NOTED ABOVE FROM 
ANOTHER UPPER LEVEL ANTICYCLONE LOCATED OVER E CENTRAL MEXICO 
NEAR 21N98W WITH A RIDGE AXIS EXTENDING WNW INTO THE E PACIFIC 
TO NEAR 22N116W. TROPICAL STORM ESTELLE IS EMBEDDED IN THE 
FAIRLY STRONG UPPER LEVEL SOUTHEASTERLY FLOW TO THE SW OF THIS 
ANTICYCLONE WHICH HAS TAKEN ITS TOLL ON THE SYSTEM.

ZONAL/EASTERLY FLOW PREVAILS ACROSS THE REMAINDER OF THE 
DISCUSSION AREA IN THE DEEP TROPICS S OF 13N. UPPER LEVEL 
MOISTURE RESULTING FROM ITCZ CONVECTION IS BEING ADVECTED TO THE 
WEST AS A RESULT OF THE PERSISTENT EASTERLY WINDS. UPPER LEVEL 
DIFFLUENCE IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ 
PARTICULARLY IN THE AREAS BETWEEN 105W AND 117W...AND BETWEEN 
120W AND 124W.  

AT THE SURFACE...A RIDGE DOMINATES THE NORTHERN WATERS 
ORIGINATING FROM 1029 MB HIGH PRES CENTERED WELL NW OF THE AREA 
NEAR 36N145W ENTERING THE DISCUSSION AREA AT 32N138W AND 
CONTINUING THROUGH 19N116W. A TIGHT PRES GRADIENT EXISTS WITH 20 
KT N WINDS AND SEAS TO 8 FT IN NW SWELL N OF 29N BETWEEN 123W 
AND 128W ALTHOUGH EXPECT THESE CONDITIONS TO DIMINISH DURING THE 
NEXT 6 HOURS AS THE PRES GRADIENT RELAXES THERE. EXPECT AN AREA 
OF NE 20 KT TRADES TO DEVELOP FROM 14N TO 18N W OF 134W BY 6 
HOURS THEN WILL PERSIST IN THE SAME GENERAL AREA THROUGH 48 
HOURS. ALSO...DIURNALLY ENHANCED NW WINDS TO 20 KT WILL OCCUR 
WITHIN 120 NM W OF THE W COAST OF BAJA CALIFORNIA FROM 24N TO 
27N DURING THE EVENING HOURS THROUGH 48 HOURS.

DISTURBANCES ALONG THE ITCZ CONTINUE TO PRODUCE AN AREA OF S TO 
SW WINDS OF 20 TO 25 KT S OF THE ITCZ TO 08N BETWEEN 100W AND 
125W AS CAPTURED BY EARLIER ASCAT SCATTEROMETER PASSES. COMBINED 
SEAS ARE 8 TO 11 FT ACROSS THIS SAME AREA DUE TO THE COMBINATION 
OF LONG PERIOD SW SWELL AND FRESHLY GENERATED WIND SEAS. THIS 
OVERALL WEATHER PATTERN WILL PERSIST DURING THE NEXT FEW DAYS. 

CROSS EQUATORIAL SW SWELLS DOMINATING THE MAJORITY OF THE 
SOUTHERN AND EASTERN PORTIONS OF THE FORECAST WATERS WILL 
GRADUALLY DECAY THROUGH TUE. A NEW SWELL TRAIN WITH PERIODS OF 
14 TO 16 SECONDS IS EXPECTED TO CROSS THE EQUATOR BETWEEN 105W 
AND 125W MON...THEN WILL SPREAD OVER MOST OF THE BASIN S OF 13N 
TO 15N BY LATE TUE.

$$
LEWITSKY