000
AXPZ20 KNHC 211531
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT APR 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH 4N77W 5N100W. ITCZ IS FROM 5N100W TO 8N120W 
2N130W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 150 NM S 
OF AXIS FROM 82W-90W AND WITHIN 60 NM S OF AXIS FROM 114W-120W.

...DISCUSSION...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER 
NORTHERN BAJA CALIFORNIA. OTHERWISE MOSTLY ZONAL UPPER LEVEL 
FLOW IS FROM 10N-25N WITH A 90-100 KT JETSTREAM FROM 17N140W TO 
15N120W. MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR AT 
THE MIDDLE AND UPPER LEVELS IS N OF 19N. UPPER LEVEL DIFFLUENT 
FLOW IS ENHANCING CONVECTION N OF THE MONSOON TROUGH WITHIN 150 
NM S OF AXIS FROM 82W-90W.

A 1014 MB HIGH IS CENTERED NEAR 22N120W. A COLD FRONT FURTHER W 
WILL APPROACH THE DISCUSSION AREA TONIGHT AND EXTEND FROM 
30N136W TO 27N140W EARLY SUN. NW WINDS ARE FORECAST TO INCREASE 
TO 20 KT W OF THE FRONT. ELY TRADES TO 20 KT AROUND THE SOUTHERN 
PERIPHERY OF THE HIGH FROM 5N-10N W OF 135W WILL DECREASE TO 
LESS THAN 20 KT TONIGHT AS THE HIGH WEAKENS.

HIGH PRES WILL BUILD BEHIND A STRONG LATE SEASON COLD FRONT 
MOVING THROUGH THE GULF OF MEXICO. THIS WILL TIGHTEN THE PRES 
GRADIENT ACROSS SOUTHERN MEXICO RESULTING IN WINDS TO GALE FORCE 
THROUGH THE GULF OF TEHUANTEPEC TONIGHT. NLY GALE FORCE WINDS 
ARE FORECAST TO INCREASE TO 40 KT MON MORNING.

$$
DGS