000
AXPZ20 KNHC 132159
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT OCT 13 2007

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE....AXIS 11N86W 15N97W 15N108W 
9N117W 12N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
NOTED WITHIN 60 NM EITHER SIDE OF LINE 12N88W 13N93W AND LINE 
12N98W 14N103W.

AN EMBEDDED SURFACE LOW PRES NEAR 14N106.5 HAS ESTIMATED SURFACE 
PRESSURE OF 1007 MB WITH CONVECTION SHEARED BETWEEN 60 AND 150 
NM W OF CENTER. THE LOW HAS MOVED W ABOUT 8 KT OVER THE PAST 24 
HOURS SO EXPECTING THAT GENERAL MOTION TO CONTINUE FOR THE NEXT 
48 HOURS...WITH POSSIBLY TROPICAL CYCLONE FORMATION.

...DISCUSSION...
AN UPPER ANTICYCLONE IS NEAR 20N127W WITH A RIDGE EXTENDING NW 
TO CREST N OF THE AREA NEAR 35N133W. AN UPPER TROUGH EXTENDS S 
INTO THE AREA ALONG 32N115W 23N118W. AN ASSOCIATED SURFACE FRONT 
IS DISSIPATING ALONG 31N116W 28N129W. AN UPPER CYCLONE IS NEAR 
7N137W WITH ITS ENVELOPE OF CYCLONIC FLOW DOMINATING THE DEEP 
TROPICS...GENERALLY S OF 12N BETWEEN 129W AND 141W.    

AN UPPER LEVEL ANTICYCLONE IS QUASI STATIONARY NEAR 19N106W WITH 
A RIDGE EXTENDING W TO A CREST AT 17N116W. THIS RIDGE EXTENDS 
OVER THE SURFACE LOW NEAR 14N106.5W AND IS SHEARING THE 
CONVECTION TO THE W OF THE LOW LEVEL CENTER. THE DEBRIS MOISTURE 
EXTENDS FROM 10N TO 20N BETWEEN 107W AND 117W. OTHERWISE THE 
UPPER LEVELS ARE DRY OVER THE DISCUSSION AREA N OF 20N AND S OF 
20N W OF 120W.

A DEEP LAYERED TROUGH EXTENDS SW ACROSS THE GULF OF MEXICO ALONG 
22N90W 16N97W 13N109W. UPPER DIFFLUENCE ALONG THIS TROUGH IS 
ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 89W AND 112W. THIS 
TROUGH SEPARATES ANTICYCLONIC FLOW OVER NORTHERN OLD MEXICO FROM 
UPPER LEVEL NE FLOW OVER THE TROPICAL E PACIFIC ASSOCIATED WITH 
A RIDGE OVER THE CARIBBEAN AND A RIDGE S OF THE EQUATOR NEAR 
7S85W.

$$
NELSON