000
AXPZ20 KNHC 210911
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JUL 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 10N85W TO A 1009 MB LOW 
PRES NEAR 07N105W TO 11N116W TO 10N126W THEN ITCZ TO BEYOND 
05N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WAS 
NOTED WITHIN 180 NM S OF THE MONSOON TROUGH BETWEEN 92W AND 
100W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED 
WITHIN 90 NM N OF MONSOON TROUGH AXIS BETWEEN 120W AND 123W. 

...DISCUSSION...
1028 MB HIGH PRESSURE IS CENTERED N OF THE FORECAST AREA NEAR 
38N142W WITH RIDGE AXIS EXTENDING SE TO NEAR 20N115W. THE 
PRESSURE GRADIENT BETWEEN THIS FEATURE AND LOWER PRES ALONG THE 
MONSOON TROUGH AND IN THE VICINITY OF THE ITCZ IS MAINTAINING 
FRESH 20 KT WINDS FROM 10N TO 18N W OF 125W AS DEPICTED BY THE 
LATEST ASCAT PASS. THIS AREA OF TRADES WILL CONTINUE THROUGH THE 
FORECAST PERIOD.

AN AREA OF LOW PRESSURE IS EMBEDDED IN THE MONSOON TROUGH NEAR 
07N105W. THIS AREA OF LOW PRESSURE WITHIN THE MONSOON TROUGH IS 
ASSOCIATED WITH A TROPICAL WAVE. THE BACKGROUND ENVIRONMENT IS 
NOT PARTICULARLY FAVORABLE FOR THE FURTHER DEVELOPMENT OF THIS 
LOW PRESSURE CENTER. 
   
SUN NIGHT INTO MON...GLOBAL MODELS CONTINUE TO INDICATE ANOTHER 
AREA OF LOW PRESSURE FORMING WITHIN THE MONSOON TROUGH AS THE 
RESULT OF THE INTERACTION OF A TROPICAL WAVE...CURRENTLY OVER 
THE WESTERN CARIBBEAN...WITH THE TOPOGRAPHY OF CENTRAL AMERICA 
AND THE MONSOON TROUGH. THE GFS HAS BACKED OFF SOMEWHAT ON THE 
DEVELOPMENT OF THIS FEATURE AND IS MORE IN LINE WITH THE OTHER 
GLOBAL MODELS.

CROSS EQUATORIAL LONG PERIOD SW SWELLS OF 21-22 SECONDS ARE NOW 
IMPACTING THE COAST OF MEXICO...CENTRAL AMERICA AND BAJA 
CALIFORNIA. THE POTENTIAL EXISTS FOR LARGE BREAKING WAVES AND 
DANGEROUS RIP CURRENTS ALONG THE COAST THROUGH THE WEEKEND AS 
THE SWELL TRAIN SLOWLY SUBSIDES. 

GAP WINDS OF 20 KT...WITH PULSES TO 25 KT ARE EXPECTED TO 
CONTINUE OVER THE GULF OF PAPAGAYO AS FRESH TRADE WIND FLOW IN 
THE SW CARIBBEAN FUNNELS THROUGH THE GAP. THE WINDS WILL BE 
GREATEST DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE 
ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW. 

FRESH GAP WINDS HAVE STARTED FUNNELING THROUGH INTO THE GULF OF 
TEHUANTEPEC THIS EVENING...LIKELY IN ASSOCIATION WITH 1019 MB 
HIGH PRESSURE CENTERED OVER THE NORTHERN GULF OF MEXICO. THIS 
GAP WIND EVENT WILL PEAK THIS MORNING WITH WINDS LOCALLY TO 30 
KT. 

$$
AL