000
AXPZ20 KNHC 142154
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN OCT 14 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 ALONG 11N86W 15N100W TO 
LOW PRES 15N108W. THEN THE ITCZ AXIS CONTINUES ALONG 10N110W 
8N125W 11N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
OBSERVED WITHIN 90 NM OF AXIS E OF 97W AND WITHIN 90 NM OF 
14N101W.

A SURFACE LOW PRES NEAR 15N108W HAS ESTIMATED SURFACE PRESSURE 
OF 1004 MB WITH CONVECTION SHEARED W OF THE EXPOSED LOW LEVEL 
CENTER WITHIN 60 NM OF LINE 14N110W 18N109W. THE LOW HAS SLOWED 
AND HAS MOVED W ABOUT 5 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 19N132W WITH A GENTLE RIDGE ALONG 
27N140W 31N130W 29N120W. AN UPPER SHORTWAVE IS MOVING SE INTO 
THE NW CORNER ALONG 34N134W 28N140W. A THIN BAND OF UPPER LEVEL 
MOISTURE IS NOTED WITH 30 NM EITHER SIDE OF LINE 24N140W 
28N127W. TO THE E OF THE UPPER RIDGE...AN UPPER TROUGH EXTENDS S 
INTO THE AREA ALONG 31N108W 25N110W 20N119W. A MID TO UPPER 
LEVEL CYCLONE IS NEAR 9N137W WITH ITS ENVELOPE OF CYCLONIC FLOW 
DOMINATING THE DEEP TROPICS...FROM 1N TO 15N BETWEEN 132W AND 
140W. THE SURFACE LOW IS WELL DEFINED NEAR 11N139W ESTIMATED AT 
1012 MB.
 
AN UPPER LEVEL ANTICYCLONE IS QUASI STATIONARY NEAR 20N102W WITH 
A RIDGE EXTENDING W TO A CREST AT 17N119W. THIS RIDGE AXIS 
EXTENDS JUST N OF THE SURFACE LOW NEAR 15N108W AND IS SHEARING 
THE CONVECTION TO THE W OF THE LOW LEVEL CENTER AS MENTIONED 
ABOVE. THE DEBRIS MOISTURE EXTENDS FROM 10N TO 21N BETWEEN 108W 
AND 120W. SOME OF THE MOISTURE IS ADVECTED NE IN THE RIDGE BUT 
SEEMS TO EVAPORATE NEAR THE SOUTHERN TIP OF THE BAJA PENINSULA. 
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 
24N84W 17N95W 16N104W 15N108W. UPPER DIFFLUENCE ALONG THIS 
TROUGH ENHANCED AFTERNOON CONVECTION AGAIN ALONG THE ITCZ 
BETWEEN 89W AND 110W...BUT SHOULD WEAKEN AFTER SUNSET. THIS DEEP 
TROUGH SEPARATES ANTICYCLONIC FLOW OVER NORTHERN OLD MEXICO FROM 
UPPER LEVEL N FLOW OVER THE TROPICAL E PACIFIC E OF 95W.

$$
NELSON