000
AXPZ20 KNHC 081526
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON OCT 08 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 1445 UTC.
  
...TROPICAL WAVE...
TROPICAL WAVE ALONG 131W MOVING W 10 TO 15 KT. ISOLATED 
CONVECTION WITHIN 120 NM OF THE WAVE AXIS BUT WITH NO 
ORGANIZATION. 

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE...AXIS 8N77W 8N90W 11N100W 
11N130W 9N140W. SCATTERED MODERATE WITHIN 60 NM OF AXIS BETWEEN 
81W AND 87W. SCATTERED MODERATE/ISOLATED STRONG FROM 10N TO 14N 
BETWEEN 88W AND 103W. SCATTERED MODERATE TO STRONG WITHIN 120 NM 
OF AXIS BETWEEN 109W AND 115W. SCATTERED MODERATE FROM 9N TO 15N 
BETWEEN 126W AND 137W. 

...DISCUSSION...

E OF 120W...
BROAD UPPER ANTICYCLONE IS CENTERED OVER W CENTRAL MEXICO NEAR 
26N78W. THIS IS WORKING IN CONCERT WITH A WEAK SURFACE TROUGH 
SHOWING UP IN SCATTEROMETER DATA ALONG 108W...AND IS PROMPTING A 
LINE OF SCATTERED MODERATE CONVECTION FROM 15N TO 18N BETWEEN 
107W AND 109W. THE CONVECTION ALONG THE ITCZ E OF 100W IS DUE IN 
PART TO ONLY LIGHT ELY SHEAR S OF THE UPPER ANTICYCLONE...AND 
ALSO IN PART TO MODERATE TO FRESH SWLY CROSS-EQUATORIAL WINDS. 
THE INCREASED SWLY FLOW IS IN RESPONSE TO A LARGE AREA OF LOW 
PRES CENTERED AROUND A LOW PRES SYSTEM IN THE NW CARIBBEAN. 
THROUGH MIDWEEK...THE LIGHT SHEAR ALOFT AND DECENT LOW LEVEL 
CONVERGENCE WILL EQUATE TO INCREASED CONVECTION ALONG THE ITCZ 
AND THE W COAST OF CENTRAL AMERICA.

W OF 120W...
UPPER TROUGH EXTENDS FROM 30N127W TO 24N140W AND CONTINUES ON TO 
HAWAII. SW OF THE TROUGH AN UPPER RIDGE AXIS EXTENDS FROM THE 
BROAD UPPER ANTICYCLONE OVER MEXICO NEAR 26N78W...TO A SMALLER 
UPPER ANTICYCLONE ALONG THE ITCZ NEAR 14N126W TO ANOTHER UPPER 
ANTICYCLONE NEAR 12N140W. THE SWLY FLOW ALOFT BETWEEN THESE 
FEATURES IS PROVIDING UPPER EXHAUST IN SUPPORT OF MODEST 
CONVECTION ALONG THE ITCZ AND TROPICAL WAVE NEAR 131W...BUT OVER 
DEEP LAYER MOISTURE REMAINS SPARSE. THE UPPER TROUGH HAS SHIFTED 
S IN RESPONSE TO STRONG SHORT WAVE ENERGY DIGGING OFF THE 
CALIFORNIA COAST. THIS IN TURN HAS PUSHED AN ASSOCIATED COLD 
FRONT S TO STALL JUST N OF THE AREA...WEAKENING A 1026 MB HIGH 
PRES AND SHIFTING IT S TO NEAR 30N. NET RESULT OF ALL THIS IS 
THAT N TO NE WINDS CONTINUE TO WEAKEN ON THE EDGE OF THE HIGH 
PRES. LIKEWISE...LARGE NLY SWELL THAT HAS BEEN PUSHING SWD WILL 
CONTINUE TO DECAY THROUGH 36 HOURS. HOWEVER...STRONG NWLY FLOW 
WELL TO THE N BEHIND THE COLD FRONT WILL DELIVER A NEW SPATE OF 
LARGE SWELL BY LATE TUE...CONTAINED MOSTLY N OF 28N AND W OF 
120W. THIS WILL CONTINUE TO SPREAD AS FAR S AS 22N BY THU AS IT 
DECAYS.

$$
CHRISTENSEN