000
AXPZ20 KNHC 061532
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT OCT 06 2007

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 1515 UTC.
  
...TROPICAL WAVE...

TROPICAL WAVE IS ALONG 121W MOVING W 10 TO 15 KT. THE WAVE SITS 
JUST W OF AN UPPER LEVEL ANTICYCLONE THAT IS PROVIDING GOOD 
DIVERGENCE ALOFT E OF THE WAVE. THIS COMBINED WITH MODERATE TO 
FRESH SWLY FLOW S OF THE ITCZ IS SUPPORTING SCATTERED CONVECTION 
E OF THE WAVE ALONG THE ITCZ. HOWEVER...THE WAVE IS DAMPENING 
OUT...AND MOVING AWAY FROM THE FAVORABLE OUTFLOW ALOFT AND INTO 
A DRIER ENVIRONMENT FURTHER W. THUS WINDS AND CONVECTION 
ASSOCIATED WITH THE WAVE WILL GRADUALLY WEAKEN OVER THE NEXT 24 
HOURS.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE...AXIS ALONG 8N82W 7N90W 14N109W 
10N130W 10N140W. SCATTERED MODERATE CONVECTION WITHIN 120 NM N 
OF AXIS BETWEEN 106W AND 110W...AND BETWEEN 117W AND 120W.

...DISCUSSION...

E OF 110W...ELY SHEAR ALOFT PERSISTS OVER PACIFIC WATERS S OF 
THE CENTRAL AMERICAN COAST...ON THE SOUTHERN EDGE OF AN UPPER 
ANTICYCLONE CENTERED OVER THE GULF OF MEXICO. AN UPPER LOW IS 
LOCATED OVER N CENTRAL MEXICO...E OF THE UPPER ANTICYCLONE. THE 
DIVERGENCE PROVIDED IN THE SWLY FLOW BETWEEN THESE FEATURES OVER 
SRN MEXICO IS ENHANCING THE SCATTERED CONVECTION N OF THE ITCZ 
BETWEEN 106W AND 110W. EARLY VISIBLE SATELLITE IMAGERY SHOWS A 
WEAK SURFACE TROUGH ORIENTED N-S ALONG 95W S OF THE GULF OF 
TEHUANTEPEC...BUT NO APPRECIABLE WINDS OR CONVECTION. NOCTURNAL 
TSTMS OFF THE COAST FROM GUATEMALA TO COSTA RICA IS DIMINISHING 
IN THE ELY SHEAR ALOFT. SHIP OBSERVATIONS SHOW FRESH NWLY FLOW 
CONTINUING TO PUSH S OF BAJA. LOOKING AHEAD...THE UPPER LOW OVER 
NRN MEXICO WILL OPEN UP AND LIFT OUT AS AN UPPER RIDGE BUILDS 
OVER CENTRAL MEXICO. S OF THIS...A WEAK UPPER LOW FORMS OVER THE 
WESTERN CARIBBEAN AND NICARAGUA. COUPLED WITH INCREASED SWLY 
SURFACE FLOW S OF THE ITCZ...NET EFFECT WILL BE AN INCREASE IN 
CONVECTION OFF THE CENTRAL AMERICAN COAST SUN AND MON. MEANWHILE 
CONVECTION OFF THE MEXICAN COAST WILL BE LIMITED BY STRONG ELY 
SHEAR ALOFT S OF THE UPPER RIDGE. THE FRESH NWLY FLOW SURGING S 
OF BAJA WILL DIMINISH.

W OF 110W...MAIN STORY IS FRESH NLY FLOW MAINLY N OF 18N AROUND 
HIGH PRES 1033 MB CENTERED TO THE NW...ACCOMPANIED BY LARGE NLY 
SWELL. THE HIGH PRES WILL WEAKEN AND SHIFT W AS A PAIR OF SHORT 
WAVE TROUGHS DIG OFF THE CALIFORNIA COAST. THIS WILL RESULT IN 
THE WINDS GRADUALLY DIMINISHING OVER THE NEXT COUPLE OF 
DAYS...ALTHOUGH THE SWELL WILL PERSIST. CONVECTION REMAINS 
LIMITED DUE TO GENERALLY DRY AIR IN MID AND UPPER LEVELS. 
HOWEVER...A SURGE OF CROSS EQUATORIAL SWLY FLOW WILL ALLOW 
MODEST CONVECTION TO PERSIST ALONG THE ITCZ BETWEEN 110W AND 
120W.

$$
CHRISTENSEN