000
AXPZ20 KNHC 071549
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI OCT 07 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.
 
...SPECIAL FEATURES...

AT 07/1500 UTC HURRICANE IRWIN WAS CENTERED NEAR 13.9N 120.4W 
MOVING W NW OR 300 DEG AT 7 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 980 MB. IRWIN IS EXPECTED TO MOVE LITTLE OVER THE 
NEXT 48 HOURS. AFTERWARD...IT IS FORECAST TO MOVE E NE IN THE 
GENERAL DIRECTION OF W CENTRAL MEXICO THROUGH 120 HOURS. MAXIMUM 
SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. ADDITIONAL 
STRENGTHENING IS FORECAST THROUGH EARLY SAT AND THEN THE SYSTEM 
IS FORECAST TO GRADUALLY WEAKEN BUT REMAIN HURRICANE STRENGTH 
THROUGH EARLY WED. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. 
SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 120 NM OF 
CENTER.

AT 07/1500 UTC TROPICAL STORM JOVA WAS CENTERED NEAR 13.7N 
110.2W MOVING NW OR 305 DEG AT 7 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 999 MB. JOVA IS EXPECTED TO MOVE MORE NORTHWARD 
THROUGH EARLY SATURDAY WITH A TURN TOWARD THE NE EXPECTED 
AFTERWARD WITH JOVA EXPECTED TO MOVE INTO W CENTRAL MEXICO BY 
EARLY TUE. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 
60 KT. ADDITIONAL STRENGTHENING IS FORECAST UNTIL POSSIBLE 
LANDFALL WITH JOVA FORECAST TO REACH HURRICANE STRENGTH BY SAT 
MORNING. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC 
FOR MORE DETAILS. NUMEROUS STRONG CONVECTION WAS NOTED WITHIN 
180 NM OF JOVA. 

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N85W TO 11N94W TO 
14N104W. THE MONSOON TROUGH HAS THEN BROKEN DOWN AS A RESULT OF 
THE CIRCULATION AROUND HURRICANE IRWIN AND TROPICAL STORM 
JOVA...THEN RESUMES FROM 12N123W TO 07N136W. THE ITCZ AXIS 
EXTENDS FROM 07N136W TO BEYOND 08N140W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION WAS NOTED WITHIN 210 NM AND 60 NM S 
OF TROUGH AXIS BETWEEN 93W AND 96W. 

...DISCUSSION...

HIGH PRESSURE 1028 MB IS CENTERED NEAR 37N133W WITH RIDGE 
EXTENDING SE TO NEAR 22N110W. THE PRESSURE GRADIENT BETWEEN THIS 
RIDGE AND LOW PRESSURE OVER MEXICO IS MAINTAINING FRESH 20 KT 
WINDS JUST W OF BAJA CALIFORNIA. ADDITIONALLY...FRESH 20 KT 
TRADEWINDS ARE S OF THE RIDGE AXIS...AND ARE EXPECTED TO SHIFT S 
OVER THE NEXT COUPLE OF DAYS. 

NW SWELL IS CONTINUING TO PROPAGATE INTO THE NORTHERN FORECAST 
WATERS WITH SEAS AS HIGH AS 12 FT IN MERGING SW AND NW SWELL. 
THE AREA OF 8 FT OR GREATER SEAS WILL CONTINUE TO PROPAGATE TO 
THE S.

CROSS-EQUATORIAL SW SWELL WITH PEAK WAVE PERIODS OF 16-18 
SECONDS CONTINUES TO PROPAGATE TO THE N AND NE...SPANNING THE 
COASTLINES OF MEXICO AND CENTRAL AMERICA. THIS SWELL WILL MERGE 
WITH THE NW SWELL CURRENTLY MOVING INTO N WATERS AS WELL AS WITH 
FRESHLY GENERATED SEAS AROUND IRWIN AND JOVA. THIS WILL RESULT 
IN A CONFUSED SEA STATE ACROSS THE CENTRAL PORTION OF THE AREA 
OVER THE WEEKEND.

$$
AL