000
AXPZ20 KNHC 031604
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI AUG 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS N OF 10N ALONG 90W. THE WAVE HAS MOVED AT 20 
TO 25 KT OVER THE PAST 24 HOURS. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS FLARING N OF 08N E OF WAVE TO THE COST OF 
CENTRAL AMERICA AT 85W. SIMILAR CONVECTION HAS BURST W OF THE 
WAVE WITHIN 60 NM OF 14N93.5W. EXPECT THE WAVE MOTION TO SLOW AS 
IT CONTINUES W OVER THE NEXT DAY OR SO WITH A NE TO E TO SE WIND 
SHIFT AT 10 TO 15 KT. 

A TROPICAL WAVE EXTENDS FROM 10N TO 17N ALONG 103W AND HAS MOVED 
W AT 10 KT OVER THE PAST 24 HOURS. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS OBSERVED FROM 07N TO 14N 99W AND 107W. 
SCATTERED STRONG CONVECTION WITH NUMEROUS LIGHTNING STRIKES IS 
ENHANCED ALONG THE NORTHERN EXTENT OF THE WAVE...FROM 16N TO 21N 
BETWEEN 100W AND 106W. THE WAVE MOTION IS NOT EXPECTED TO CHANGE 
OVER THE NEXT DAY OR SO WITH A NE TO E TO SE WIND SHIFT AT 5 TO 
10 KT.

A TROPICAL WAVE EXTENDS FROM 10N TO 18N ALONG 120W AND HAS MOVED 
W AT 10 KT OVER THE PAST 24 HOURS. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS OBSERVED WITHIN 180 NM W AND WITHIN 300 NM 
E OF THE WAVE AXIS. THE WAVE MOTION IS NOT EXPECTED TO CHANGE 
OVER THE NEXT DAY OR SO WITH A NE TO E TO SE WIND SHIFT AT 15 KT 
OVER THE WATERS N OF 13N ALONG THE WAVE.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS W FROM THE NW COAST OF COLOMBIA 
AT 10N75W TO THE W COAST OF COSTA RICA AT 10N86W TO THE SOUTHERN 
SEGMENT OF A TROPICAL WAVE AT 10N103W WHERE LOW LEVEL WINDS 
INDICATE A TRANSITION TO THE ITCZ. THE ITCZ DIPS S TO 09N110W 
AND IS THEN STRETCHED N TO 12N120W BY A TROPICAL WAVE. THE ITCZ 
THEN TURNS SW TO 07N132W AND CONTINUES W TO BEYOND 08N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ELSEWHERE 
WITHIN 120 NM OF THE MONSOON TROUGH AND ITCZ...ALONG 07N78W TO 
09N100W TO 08N115W TO 12N120W TO 07N137W.

...DISCUSSION...
SEVERAL UPPER CYCLONES ARE NOTED JUST N OF THE AREA. THE 
WESTERNMOST CYCLONE IS AT 33N145W WITH A TROUGH EXTENDING SE TO 
27N137W. ANOTHER UPPER CYCLONE IS AT 33N129W WITH AN UPPER 
TROUGH EXTENDING SE TO 25N123W THEN TURNING SW TO 17N132W. SOME 
UPPER MOISTURE IS NOTED N OF 25N E OF THE TROUGH AND IS 
SPREADING N ACROSS THE NORTHERN PORTION OF THE BAJA CALIFORNIA 
PENINSULA AND ACROSS EXTREME SE CALIFORNIA AND WESTERN ARIZONA. 
A THIRD UPPER CYCLONE IS OVER S CENTRAL ARIZONA WITH A DEEP 
LAYERED TROUGH EXTENDING S INTO YET ANOTHER UPPER CYCLONE AT 
21N111W...WITH DRY UPPER AIR OBSERVED WITHIN 180 NM EITHER SIDE 
OF THE TROUGH AXIS. 

AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS AT 13N134W WITH A 
RIDGE EXTENDING N TO A CREST AT 29N133W. VERY DRY UPPER AIR 
ACCOMPANIES THIS RIDGE OVER THE AREA N OF 17N W OF 123W. THE 
ASSOCIATED UPPER DIFFLUENCE IS ENHANCING THE CONVECTION ALONG 
THE ITCZ BETWEEN 123W AND 140W AS PREVIOUSLY DESCRIBED.

ANOTHER UPPER ANTICYCLONE IS AT 18N119W WITH A RIDGE EXTENDING N 
TO A SHARP CREST AT 28N116W...AND A SECOND UPPER RIDGE EXTENDS 
SE TO CREST AT 11N106W. THE NORTHERN RIDGE IS PHASE WITH THE 
TROPICAL WAVE ALONG 120W AND IS SUPPORTING THE CONVECTION 
PREVIOUSLY MENTIONED. THE SE RIDGE IS ENHANCING THE BELT OF ITCZ 
CONVECTION ALONG THE ITCZ FROM 06N TO 11N BETWEEN 103W AND 
112W.  

ANOTHER UPPER CYCLONE IS OVER THE MEXICAN COAST AT 19N105W AND 
IS ENHANCING THE STRONG CONVECTION ASSOCIATED WITH THE TROPICAL 
WAVE ALONG 103W.       

AN UPPER TROUGH EXTENDS SW ACROSS THE WESTERN CARIBBEAN AND 
ACROSS BELIZE TO OVER THE TROPICAL PACIFIC THROUGH 13N95W TO 
09N100W. FURTHER E...A BROAD UPPER RIDGE EXTENDS FROM COLOMBIA 
CROSS THE PACIFIC E OF 85W. ONLY SLIGHT ENHANCEMENT OF 
CONVECTION IS INDICATED E OF THIS UPPER TROUGH. 

ELSEWHERE AT THE LOW LEVELS...A RIDGE EXTENDS SE INTO THE AREA 
FROM 32N140W TO 12N122W. NE TRADES AT 20 TO 25 KT ARE ENHANCED 
SW OF THE RIDGE IN THE AREA FROM 10N TO 15N TO W OF 135W. LITTLE 
CHANGE IS EXPECTED OVER THE NEXT 24 HOURS...THEN THE RIDGE WILL 
RETRACT N AND THE ASSOCIATED TRADES WILL WEAKEN. 

CROSS-EQUATORIAL LONG PERIOD S SWELL OF 16 TO 18 SECONDS HAS 
PROPAGATED INTO THE PACIFIC WATERS S OF 04N BETWEEN 80W AND 88W 
AND IS EXPECTED TO CONTINUE N TO REACHING ALONG 08N IN 24 TO 48 
HOURS. SOUTHEASTERLY SWELL HAS CROSSED THE EQUATOR TO ALONG 04N 
BETWEEN 93W AND 128W...AND IS EXPECTED TO PROPAGATE ACROSS THE 
ENTIRE AREA S OF 08N BETWEEN 92W AND 138W IN ABOUT 48 HOURS WITH 
COMBINED SEAS SUBSIDING FROM A MAX OF 10 FT TODAY TO MAX OF 8 FT 
BY THE END OF THE WEEKEND.

$$
NELSON