000
AXPZ20 KNHC 302121
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI SEP 30 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.

...SPECIAL FEATURE...
POST-TROPICAL CYCLONE HILARY HAS AN EXPOSED LOW-LEVEL CENTER 
NEAR 23.6N 122.0W AT 2100 UTC...MOVING NW OR 325 DEG AT 6 KT 
WITH A CENTRAL PRES OF 1007 MB. MAXIMUM SUSTAINED WINDS 30 GUSTS 
TO 40 KT. POST-TROPICAL CYCLONE HILARY IS EXPECTED TO CONTINUE 
TO WEAKEN AND BECOME A REMNANT LOW TONIGHT. SEAS GENERATED BY 
HILARY WILL CONTINUE TO SUBSIDE THROUGH THE WEEKEND. SEE THE 
LAST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. 
 
...ITCZ/MONSOON TROUGH...
MONSOON TROUGH FROM 10N86W TO 14N93W TO 09N109W TO 10N130W TO 
09.5N135W THEN ITCZ FROM 09.5N135W TO BEYOND 09N140W. SCATTERED 
MODERATE WITHIN 210 NM S OF TROUGH AXIS BETWEEN 99W AND 106W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 150 NM S OF 
TROUGH BETWEEN 110W AND 118W. SCATTERED MODERATE CONVECTION 
WITHIN 120 NM S OF AXIS BETWEEN 120W AND 127W.

...DISCUSSION...
A COLD FRONT EXTENDS FROM 30N131W TO 26N140W. THE FRONT IS 
WEAKENING AND IS EXPECTED TO DISSIPATE WITHIN THE NEXT 24 TO 36 
HOURS. WINDS BEHIND THE FRONT ARE BELOW 20 KT AS NOTED IN AN 
EARLIER ASCAT PASS...BUT SEAS ARE NEAR 8 FT IN NW SWELL. SEAS 
ARE EXPECTED TO PEAK AT AROUND 8-9 FT DURING THE 12-24 HOURS.

FURTHER SOUTH...TRADE WIND FLOW REMAINS LIGHT TO MODERATE 
BETWEEN THE MONSOON TROUGH AND 20N W OF 110W...DUE TO WEAK HIGH 
PRES TO THE N. RESIDUAL NORTHERLY SWELL TO 8 FT WILL DECAY 
THROUGH THE REMAINDER OF THE DAY IN THIS SAME AREA.

HIGH PRES BUILDING BEHIND A COLD FRONT MOVING ACROSS THE GULF OF 
MEXICO THROUGH SAT WILL INDUCE AN ENHANCED PRES GRADIENT AND 
STRONG WINDS IN THE CHIVELAS PASS AND GULF OF TEHUANTEPEC BY 
EARLY SAT. PEAK NORTHERLY WINDS ARE EXPECTED TO REACH 25-30 
KT...BELOW GALE FORCE...LATE SAT NIGHT THROUGH SUN AFTERNOON.

MODERATE TO FRESH SW WINDS CONVERGING INTO THE MONSOON TROUGH 
ARE GENERATING AREAS OF MODERATE TO STRONG CONVECTION BETWEEN 
05N TO 09N E OF 90W.

$$
CHRISTENSEN