000
AXPZ20 KNHC 312134
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED OCT 31 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURE...
TROPICAL STORM ROSA CENTERED NEAR 14.2N 117.9W AT 2100 UTC OCT 31
MOVING W OR 260 DEGREES AT 3 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WINDS ARE 45 KT GUSTS TO 
55 KT. A 1706 UTC ASCAT PASS CONFIRMED THE LOCATION. WESTERLY 
SHEAR IS DISPLACING THE CONVECTION E OF THE LOW-LEVEL CENTER. 
NUMEROUS STRONG CONVECTION ASSOCIATED WITH ROSA IS FROM 13N TO 
16N BETWEEN 113W AND 118W. ROSA WILL SLOWLY WEAKEN ON THU AND 
WEAKEN FURTHER TO TROPICAL DEPRESSION FRI NIGHT. ROSA IS 
FORECAST TO MOVE VERY LITTLE DURING THE NEXT FEW DAYS. SEE 
LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH IS FROM 08N80W TO 06N95W TO LOW PRES NEAR 15N109W 
1012 MB TO 16N113W. ITCZ IS FROM 12N130W TO 08N140W. SCATTERED 
MODERATE CONVECTION IS FROM 05N TO 08N BETWEEN 86W AND 88W...AND 
FROM 06N TO 09N BETWEEN 134W AND 139W.

...DISCUSSION...
UPPER LEVEL RIDGE ACROSS THE FAR NW PORTION OF THE DISCUSSION 
AREA FROM 32N123W TO 24N129W. DOWNSTREAM UPPER LEVEL SHORTWAVE 
TROUGH WITH AXIS FROM SOUTHERN CALIFORNIA TO 33N115W TO 25N120W. 
A 80 KT JETSTREAM IS NW OF THE RIDGE FROM 30N140W TO CENTRAL 
CALIFORNIA. AN UPPER LEVEL HIGH IS CENTERED OVER THE TROPICS 
NEAR 13N130W. ANTICYCLONIC CIRCULATION DOMINATES FROM EQ-23N W 
110W. THE BASE OF AN UPPER LEVEL TROUGH IS S OF S MEXICO N OF 
10N E OF 105W. MODERATE TO STRONG SUBSIDENCE WITH DRY AND STABLE 
AIR AT THE MIDDLE AND UPPER LEVELS IS N OF 20N INCLUDING THE 
BAJA CALIFORNIA PENINSULA AND NORTH-CENTRAL MEXICO.

A 1019 MB SURFACE HIGH IS CENTERED TO 27N126W WITH RIDGE FROM 
THE HIGH SE TO NEAR 23N114W. NE TRADE WINDS REMAIN RATHER LIGHT 
TO THE S OF THE RIDGE WITH SPEEDS OF 10-15 KT.

COLD FRONT ACROSS THE FAR NW PORTION OF THE AREA EXTENDING FROM 
30N135W TO 27N140W. THE FRONT WILL WEAKEN AND EXTEND FROM 
30N131W TO 27N140W THU THEN DISSIPATE FRI. NW SWELL BEHIND THE 
FRONT WILL BUILD SEAS 8 TO 10 FT.

A 1012 MB LOW PRES IS ANALYZED ALONG THE MONSOON TROUGH CENTERED 
NEAR 15N109W. NUMEROUS MODERATE TO STRONG FROM 12N TO 15N 
BETWEEN 106W AND 110W...AND FROM 14N TO 16N BETWEEN 110W AND 
112W.

ELY WINDS 20-25 KT ARE BLOWING THROUGH THE GULF OF PAPAGAYO ARE 
EXPECTED TO CONTINUE UNTIL THU EVENING THEN DECREASE TO LESS 
THEN 20 KT.

$$
FORMOSA