000
AXPZ20 KNHC 121606
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI OCT 12 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.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE...AXIS ALONG 14N91W  11N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 11N TO 15N
E OF 110W.

SCATTERED STRONG CONVECTION WITHIN 120 NM W QUADRANT OF LOW PRES 
CENTER AT 14N103W.

...DISCUSSION...
TWO STRONG FEATURES DOMINATE MID/UPPER LEVELS TODAY.  FIRST... 
WEAK TROUGH FROM 32N119W TO 29N130W HAS SHORT WAVE TROUGH ROUND 
ITS BASE THEN RACING NE CARRYING ALONG THE SUPPORT FOR SURFACE 
COLD FRONT APPROACHING 30N.  FRONT EXPECTED TO DENT INTO E PAC 
WATERS BEFORE STALLING AND DIFFUSE AS UPPER TROUGH LIFTS NE. 
WITHIN 24 HRS.  

DOWNSTREAM...BROAD RIDGE MADE UP BY THREE ANTICYCLONIC GYRES ONE 
AT 17N120W...A SECOND ONE AT 21N108W AND A THIRD AT 19N100W OVER 
CENTRAL MEXICO.  SRN PERIPHERY OF RIDGE BECOMES USEFUL VENUE FOR 
TROPICAL MOISTURE FROM CARIBBEAN SEA ADVECTING INTO E PAC. UPPER 
MODERATE EASTERLY FLOW EXTEND AS FAR AS EQUATOR INHIBITING ANY 
DEEP CONVECTION S OF 10N COMBINED WITH A LACK OF MECHANICAL 
UPLIFTING FEATURES. 

AT THE SURFACE...WEAK COLD FRONT APPROACHING 30N WILL BARELY 
ENTER E PAC BEFORE SUPPORTING UPPER TROUGH LIFTS NE.  FRONT 
BECOMES DIFFUSE IN LESS THAN 24 HRS AND DISSIPATES LEAVING ONLY 
LARGE LONG PERIOD NLY SWELLS N OF 20N.  

LOW PRES 1005 MB AT 14N103W HAS SCATTERED DEEP CONVECTION 
RUNNING WELL W OF AXIS AS UPPER ELY FLOW ON S SIDE OF RIDGE 
PREVENTS MORE SIGNIFICANT DEVELOPMENT.  GLOBAL MODELS MAINTAIN 
LOW PRES CENTER MEANDERING AIMLESSLY ALONG 15N THROUGH ENTIRE 
FORECAST PERIOD WITHOUT INTENSIFYING IT NOR KILLING IT. FORECAST 
INCLUDES LOW PRES AS PROMOTER OF LONG STRETCH OF STRONG SW WINDS 
AND SEAS JUST S OF ITCZ LASTING THROUGH 48 HRS.   

$$
WALLY BARNES