000
AXPZ20 KNHC 132132
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN NOV 13 2011

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

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

MONSOON TROUGH FROM 09N84W TO 07N94W. ITCZ AXIS FROM 07N94W TO 
11N128W WHERE THERE IS A BREAK DUE TO A TROUGH FROM 13N129W TO 
08N136W. THE ITCZ THEN RESUMES FROM 08N137W TO 08N140W. NO 
SIGNIFICANT CONVECTION WAS NOTED.

...DISCUSSION...

DEEP LAYER LOW PRES SYSTEM CENTERED NEAR 30N118W WITH AN 
ESTIMATED SURFACE PRES AROUND 1008 MB WILL GRADUALLY DISSIPATE 
THROUGH EARLY MON AS IT MOVES INTO NORTHERN BAJA CALIFORNIA. 
STRONG SURFACE HIGH PRES 1031 MB IS CENTERED NW OF THE AREA NEAR 
37N146W HAS SURFACE RIDGE EXTENDING SE TO NEAR 18N117W. THE 
PRESSURE GRADIENT BETWEEN THIS AREA OF HIGH PRESSURE AND THE LOW 
PRESSURE CENTER IS MAINTAINING FRESH TO STRONG NW TO N WINDS W 
OF THE SURFACE LOW. WINDS WILL DIMINISH BELOW 20 KT AS THE LOW 
DISSIPATES BY TOMORROW. 

THE PRESSURE GRADIENT BETWEEN THE RIDGE AND LOWER PRESSURE IN 
THE VICINITY OF THE ITCZ IS MAINTAINING FRESH 20 KT TRADES FROM 
THE ITCZ TO NEAR 20N AND W OF 130W. THIS AREA OF TRADES WILL 
MAINTAIN THROUGH THE FORECAST PERIOD. 

NW SWELL WITH HEIGHTS OF 8 TO 13 FT AND PERIODS TO 10 TO 14 
SECONDS CONTINUES TO SWEEP SE AS IT CONTINUES TO SLOWLY SUBSIDE. 
THE SWELL WILL COVER THE AREA W OF 110W BY 24 HOURS WITH 
COMBINED SEAS TO 10 FT.

ENHANCED GRADIENT WIND FLOW OVER THE SW CARIBBEAN ALONG WITH 
OVERNIGHT DRAINAGE EFFECTS OFF THE HIGH TERRAIN OF NORTHERN 
COSTA RICA WILL PRODUCE WINDS TO 20 KT THROUGH THE GULF OF 
PAPAGAYO DURING THE LATE NIGHT AND EARLY MORNING THROUGH TUE.  

THE MONSOON TROUGH OVER THE FAR SW CARIBBEAN REMAINS ACTIVE. 
FAVORABLE ENVIRONMENTAL BACKGROUND FLOW WILL REMAIN FAVORABLE 
FOR SUSTAINED CONVECTIVE ACTIVITY ALONG THE MONSOON 
TROUGH...WITH THE ACTIVITY SLOWLY SPREADING WESTWARD OVER THE 
NEXT DAY OR SO. FORMATION OF A LOW PRES CENTER WITHIN THE 
MONSOON TROUGH OVER THE FAR E PART OF THE AREA IS POSSIBLE 
WITHIN THE NEXT 2-3 DAYS WITH ENHANCED SW MONSOONAL FLOW HELPING 
MAINTAIN SEAS TO 8 FT OVER THE FAR SE PART OF THE FORECAST AREA.

$$
AL