000
AXPZ20 KNHC 072129
TWDEP 

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

AT 07/2100 UTC HURRICANE IRWIN WAS CENTERED NEAR 14.0N 120.9W 
MOVING W NW OR 295 DEG AT 5 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE WAS 977 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 WAS 80 KT WITH GUSTS TO 100 KT. ADDITIONAL 
STRENGTHENING IS FORECAST THROUGH EARLY SAT AND THEN THE SYSTEM 
IS FORECAST TO GRADUALLY WEAKEN BUT REMAIN HURRICANE STRENGTH 
THROUGH WED. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. 
NUMEROUS STRONG CONVECTION WAS WITHIN 120 NM OF CENTER.

AT 07/2100 UTC TROPICAL STORM JOVA WAS CENTERED NEAR 14.6N 
110.4W MOVING N NW OR 335 DEG AT 7 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE WAS 997 MB. JOVA IS EXPECTED TO MOVE 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 WAS 55 KT WITH GUSTS TO 65 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. 

LOW PRESSURE 1008 MB IS CENTERED NEAR 11N95W AND MOVING WESTWARD 
AT 5 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WAS 
NOTED WITHIN 120 NM OF THE LOW. UPPER LEVEL WINDS ARE SOMEWHAT 
CONDUCIVE FOR CONTINUED DEVELOPMENT OF THE LOW...AND THERE IS A 
MEDIUM CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE WITHIN THE 
NEXT 48 HOURS. 

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH ALONG 10N86W TO 1008 MB LOW PRES NEAR 11N95W TO 
16N106W WHERE THERE IS A BREAK IN THE TROUGH DUE TO THE 
CIRCULATION AROUND HURRICANE IRWIN AND TROPICAL STORM JOVA. THE 
MONSOON TROUGH THEN RESUMES FROM 13N124W TO 1009 MB LOW PRES 
NEAR 10N130W TO 08N135W. THE ITCZ EXTENDS FROM 08N135W TO BEYOND 
08N140W. SCATTERED MODERATE WITHIN 90 NM OF FIRST LOW AND FROM 
08N TO 14N BETWEEN 96W AND 98W. SIMILAR CONVECTION IS FROM 16N 
TO 19N BETWEEN 104W AND 108W. ISOLATED TO SCATTERED MODERATE 
WITHIN 90-120 NM SW QUADRANT OF SECOND LOW.

...DISCUSSION...

HIGH PRESSURE 1030 MB IS CENTERED NEAR 37N135W WITH RIDGE 
EXTENDING SE TO NEAR 22N107W. THE PRESSURE GRADIENT BETWEEN THIS 
RIDGE OF HIGH PRESSURE AND THE COMBINED AREA OF LOW PRESSURE 
ASSOCIATED WITH HURRICANE IRWIN AND TROPICAL STORM JOVA IS 
PRODUCING FRESH 20 KT TRADEWINDS JUST S OF THE RIDGE AXIS AS 
DEPICTED BY THE LATEST 1812 UTC ASCAT PASS. ADDITIONALLY...THE 
PRESSURE GRADIENT BETWEEN THE RIDGE AND TROUGHING OVER MEXICO IS 
MAINTAINING FRESH 20 KT WINDS OVER THE GULF OF CALIFORNIA. 

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