000
AXPZ20 KNHC 070354
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED NOV 07 2012

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0345 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS W FROM THE BORDER OF PANAMA AND 
COLOMBIA NEAR 08N78W ACROSS PANAMA TO 09N99W THEN DROPS SW TO 
07N105W AND THEN NW TO 10N112W WHERE IT LOSES IDENTITY. LOW 
LEVEL WINDS INDICATE THAT THE ITCZ AXIS FORMS NEAR 08N113W AND 
EXTENDS SW TO 06N123W...THEN NW TO BEYOND 08N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 150 NM 
EITHER SIDE OF A LINE FROM 06N81W TO 08N86W TO 08N101W. ISOLATED 
STRONG CONVECTION IS OBSERVED WITHIN 30 NM EITHER SIDE OF A LINE 
FROM 12N93W TO 12N100W.
  
...DISCUSSION...

AN UPPER CYCLONE IS CENTERED AT 25N130W WITH AN UPPER TROUGH 
EXTENDING S TO BASE OVER THE DEEP TROPICS AT 09N132W. AN UPPER 
ANTICYCLONE IS OVER THE TROPICS AT 13N102W WITH AN UPPER RIDGE 
EXTENDING NW TO A CREST OVER NW MEXICO AT 29N110W. AN UPPER WIND 
MAX...AND AN AREA OF UPPER DIFFLUENCE...IS NOTED ALONG THE W 
PERIPHERY OF THE RIDGE...ROUGHLY WITHIN 150 NM EITHER SIDE OF A 
LINE FROM 15N122W TO 25N113W. SCATTERED MODERATE CONVECTION IS  
OBSERVED WITHIN 30 NM EITHER SIDE OF A LINE FROM 15N120W TO 
18N120W AND IS THE REMNANTS OF A SURFACE LOW THAT DISSIPATED 
LATE TUE. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
OBSERVED WITHIN 30 NM OF 21N110W IS THE REMNANTS OF A SECOND 
SURFACE LOW THAT HAS LOST IDENTITY. UPPER DEBRIS MOISTURE... 
SOME OF WHICH ORIGINATED NEAR THESE SURFACE LOWS...IS OBSERVED 
WITHIN 240 NM EITHER SIDE OF A LINE FROM 15N122W TO  
23N114W...THEN THE MOISTURE PLUME TURNS E ACROSS THE SOUTHERN 
TIP OF THE BAJA CALIFORNIA PENINSULA TO OVER MEXICO AT 23N101W. 
UPPER DIFFLUENCE ELSEWHERE UNDER THE TROPICAL RIDGE IS ENHANCING 
THE CONVECTION PREVIOUSLY DESCRIBED WITH THE DEBRIS MOISTURE 
ROTATING ANTICYCLONICALLY AROUND THE RIDGE...AND ACROSS THE SW 
GULF OF MEXICO...TURNING CYCLONICALLY NE ACROSS THE SE GULF OF 
MEXICO.  

THE UPPER CYCLONE AT 25N130W IS EXPECTED TO RAPIDLY FILL BY LATE 
WED AS A LONG WAVE TROUGH TO ITS N AMPLIFIES SOUTHWARD AND 
ROTATES EASTWARD ACROSS THE WESTERN CONUS DRAGGING A WEAK FRONT 
OR TROUGH ACROSS THE NE WATERS OF THE DISCUSSION AREA ON THU. 
SURFACE HIGH PRESSURE WILL BUILD SE OVER THE NW PORTION 
INCREASING THE NW FLOW TO 20 TO 25 KT LATE WED NIGHT AND 
BUILDING SEAS TO 8-11 FT IN NE SWELL...IN THE WATERS N OF 27N W 
OF 128W. 

GAP WINDS...NE WINDS ARE SURGING THROUGH THE ISTHMUS OF 
TEHUANTEPEC AT 20 TO 30 KT AND EXPECTED TO INCREASE TO A MINIMAL 
GALE BY MIDNIGHT. EXPECT THE LOW LEVEL FLOW TO INCREASE 
TO A MAX OF 40 KT WITH SEAS BUILDING TO 14 FT ON WED. GALE 
CONDITIONS ARE EXPECTED TO PERSIST THROUGH SUNRISE FRI 
MORNING...THEN DIMINISH. EXPECT NE WINDS TO INCREASE TO 15 
TO 20 KT TONIGHT IN THE GULF OF PAPAGAYO AND FURTHER INCREASE TO 
20 TO 25 KT ON WED AFTERNOON. THE RESULTANT NE SWELL WILL 
PROPAGATE W TO ALONG 94W...MERGING WITH THE SWELL ORIGINATING 
FROM THE NORTHERLY WINDS SURGING THROUGH THE GULF OF 
TEHUANTEPEC. 

CROSS EQUATORIAL SOUTHERLY SWELL...RESULTING IN SEAS TO 8 
FT...IS OBSERVED IN THE AREA SW OF LINE FROM 08N140W TO 00N125W. 
THE SOUTHERLY SWELL WILL CONTINUE TO PROPAGATE N TO ALONG ABOUT 
07N EVERYWHERE W OF 97W ON WED...THEN SHRINK TO BETWEEN 95W AND 
118W ON THU. THE SOUTHERLY SWELL WILL MIX WITH THE SHORTER 
PERIOD NE SWELL EMERGING OUT OF THE TEHUANTEPEC GAP WIND EVENT 
RESULTING IN AN AREA OF CONFUSED SEAS FROM 08N TO 14N BETWEEN 
95W AND 115W ON THU. 

$$
NELSON