000
AXPZ20 KNHC 202130
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH IS FROM 09N83W TO 06N90W TO 05N100W TO 06N120W TO 
05N125W. ITCZ IS FROM 05N125W TO 06N140W. SCATTERED MODERATE 
CONVECTION IS FROM 06N TO 09N BETWEEN 115W AND 125W. 

...DISCUSSION...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 31N119W.
OTHERWISE MOSTLY ZONAL UPPER LEVEL FLOW IS FROM 10N-25N WITH AN 
80 KT JETSTREAM FROM 15N140W TO 15N120W TO ACROSS SOUTHERN 
MEXICO AT 20N97W. MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE 
AIR AT THE MIDDLE AND UPPER LEVELS IS N OF 15N. IN THE DEEP 
TROPICS AN UPPER LEVEL HIGH IS CENTERED NEAR 10N100W. UPPER 
LEVEL DIFFLUENT FLOW IS ENHANCING CONVECTION N OF THE ITCZ FROM 
110W-120W.

A 1024 MB HIGH IS CENTERED NEAR 33N135W. A COLD FRONT FURTHER W 
WILL APPROACH THE DISCUSSION AREA SAT NIGHT. 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 05N-10N W OF 
135W WILL DECREASE TO LESS THAN 20 KT BY SAT 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 SAT NIGHT.

$$
FORMOSA