000
AXPZ20 KNHC 130915
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

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

MONSOON TROUGH EXTENDS FROM 10N85W TO 08N97W. ITCZ AXIS IS FROM 
08N97W TO 10N125W...THEN RESUMES FROM 07N135W TO 07N140W. 
SCATTERED MODERATE CONVECTION LOCATED NEAR 7.5N133W.

...DISCUSSION...

STRONG HIGH PRESSURE 1031 MB CENTERED NW OF THE AREA HAS RIDGE 
EXTENDING SE TO NEAR 20N125W. LOW PRESSURE 1006 MB IS CENTERED 
NEAR 30N119W. ASCAT PASS DIRECTLY OVER THE LOW AT 0442 UTC SHOWS 
WINDS HAVE SUBSIDED BELOW GALE FORCE...MOSTLY 25 KT NEAR THE LOW 
CENTER WITH A FEW 30 KT WIND BARBS MAINLY IN THE S QUADRANT. THE 
LOW IS EXPECTED TO SLOWLY DISSIPATE OVER THE NEXT 24-36 HOURS AS 
IT DRIFTS SW TO THE BAJA PENINSULA WHILE THE HIGH REMAINS NEARLY 
STATIONARY NW OF THE AREA NEAR 37N145W. PRES GRADIENT BETWEEN 
THE RIDGE AND THE ITCZ IS SUPPORTING FRESH TRADES FROM 11N TO 
16N W OF 135W BASED ON SCATTEROMETER DATA. THIS AREA OF TRADES 
WILL LINGER THROUGH MOST OF THE FORECAST PERIOD. A TIGHT PRES 
GRADIENT BETWEEN THE LOW NEAR BAJA AND HIGH PRES OVER THE SW 
U.S. IS MAINTAINING FRESH S TO SW WINDS OVER THE FAR N PART OF 
THE GULF OF CALIFORNIA. THESE WINDS ARE EXPECTED TO DIMINISH 
BELOW 20 KT LATER THIS MORNING.  

NW SWELL WITH SEAS TO 16 FT PREVAIL OVER A LARGE PORTION OF THE 
FORECAST AREA NW OF LINE FROM 25N112W TO 05N140W. NW SWELL WILL
CONTINUE TO SPREAD SE AND ENCOMPASS MUCH OF THE AREA W OF 110W 
BY MON NIGHT...ALTHOUGH OVERALL SEA HEIGHTS WILL SUBSIDE TO NO 
MORE THAN 10 FT AS THE SWELL DECAYS.

WINDS HAVE DIMINISHED BELOW 20 KT OVER THE GULF OF TEHUANTEPEC. 
SUBSIDING NE SWELL GENERATED FROM THE HIGH WIND EVENT EXTEND TO 
109W. COMBINED SEAS WILL FALL BELOW 8 FT BY THIS EVENING. 

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.  

FAVORABLE ENVIRONMENTAL CONDITIONS S OF PANAMA HAS RESULTED IN 
AN ACTIVE MONSOON TROUGH OVER THIS AREA. BACKGROUND FLOW WITHIN 
THE MONSOON TROUGH WILL REMAIN FAVORABLE FOR SUSTAINED CONVECTIVE
ACTIVITY SLOWLY SPREADING WESTWARD OVER THE NEXT DAY OR SO.  
FORMATION OF A BROAD LOW PRES CENTER WITHIN THE MONSOON TROUGH 
IS LIKELY WITHIN THE NEXT 2-3 DAYS WITH ENHANCED SW MONSOONAL 
FLOW HELPING BUILD SEAS TO 8-9 FT IN THE GULF OF PANAMA.

$$
MUNDELL