000
AXPZ20 KNHC 310905
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE JUL 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0830 UTC.

...TROPICAL WAVES...

TROPICAL WAVE FROM 15N104W TO 09N105W. THUNDERSTORM ACTIVITY HAS 
WANED THIS EVENING AND NO SIGNIFICANT DEEP IS PRESENT.  DESPITE 
THIS...THE WAVE RETAINS A ROBUST MID-LEVEL CIRCULATION AND IS 
DISCERNIBLE AT THE SURFACE AS SHOWN BY THE 0436Z ASCAT PASS.  
THE WAVE SHOULD CONTINUE MOVING WESTWARD AT 10 TO 15 KT ALONG 
THE NORTH SIDE OF THE ITCZ. THE SYSTEM SHOULD REMAIN OVER WARM 
29C WATERS...WITHIN MOIST LOWER LEVELS...AND EXPERIENCING LOW 
EASTERLY VERTICAL SHEAR.  HOWEVER...NONE OF THE GLOBAL MODELS 
SPIN UP THE WAVE INTO A TROPICAL CYCLONE.  THIS MAY BE BECAUSE 
THE WAVE IS WELL WEST OF THE MONSOON TROUGH AND THUS LACKS 
SYNOPTIC SCALE VORTICITY AND LOW LEVEL CONVERGENCE.  FURTHER 
DEVELOPMENT THUS SEEMS UNLIKELY AND THE WAVE SHOULD CONTINUE 
WESTWARD OVER THE NEXT FEW DAYS WHILE GRADUALLY WEAKENING.

TROPICAL WAVE FROM 17N86W IN THE NW CARIBBEAN SEA ACROSS 
HONDURAS TO 10N87W IN THE NE PACIFIC.  MONDAY AFTERNOON...DEEP 
CONVECTION E OF THE WAVE AXIS WAS QUITE EXTENSIVE AND A 
MID-LEVEL ROTATION IS EVIDENT OVER THE SW CARIBBEAN SEA.  THE 
WAVE MAY ALSO BE ENHANCING A WEAK PAPAGAYO GAP WIND EVENT...AS 
20 KT E WINDS WERE OBSERVED FROM A 0256Z ASCAT PASS JUST WEST OF 
NICARAGUA. IT APPEARS THAT THIS WAVE IS WEAK IN AMPLITUDE AND 
COMBINED WITH IT MOVING AWAY FROM THE MONSOON TROUGH ENVIRONMENT 
SUGGESTS THAT THIS IS NOT A GOOD CANDIDATE FOR CYCLOGENESIS 
EITHER.  NONE OF THE GLOBAL MODELS INDICATE FURTHER TROPICAL 
DEVELOPMENT OF THIS WAVE.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 08N78W TO 09N86W. THE INTERTROPICAL 
CONVERGENCE ZONE AXIS EXTENDS FROM 09N88W TO 10N103W THEN 
RESUMES FROM 09N108W TO 07N120W TO 09N140W. SCATTERED MODERATE 
IS WITHIN 120 NM OF ITCZ BETWEEN 97W AND 102W.

...DISCUSSION...

IN THE UPPER LEVELS...RIDGING EXTENDS NORTHEASTWARD FROM 11N140 
TO BAJA CALIFORNIA NEAR 25N111W TO A QUITE LARGE AND HIGH 
AMPLITUDE RIDGE CENTERED OVER TEXAS AND OKLAHOMA NEAR 35N98W.  
EQUATORWARD OF THIS RIDGE...THE UPPER LEVEL FLOW IS GENERALLY E 
TO NE 15 TO 25 KT.  AN UPPER LOW IS CENTERED OVER CENTRAL 
MEXICO...WHICH IS INDUCING A LIMITED AREA OF WESTERLY WINDS ON 
THE EQUATORWARD SIDE OF THE LOW.  

AT LOWER LEVELS...1028 MB SURFACE HIGH PRES REMAINS CENTERED NW 
OF THE AREA NEAR 36N140W WITH A RIDGE EXTENDING SE FROM THE HIGH 
TO 23N116W. THE RESULTING MODEST PRES GRADIENT BETWEEN THIS 
RIDGE AND LOWER PRES NEAR THE ITCZ IS PRODUCING A ZONE OF 20 KT 
NE TRADES FROM 10N TO 20N W OF 130W.  SEAS TO 9 FT ARE ALSO 
ACCOMPANYING THESE WINDS. THESE CONDITIONS WILL NOT CHANGE MUCH 
IN INTENSITY THROUGH THE NEXT 24-48 HOURS...BUT MAY CONTRACT 
SOMEWHAT IN AREAL EXTENT.

WEAK GAP WIND EVENTS CONTINUE FOR BOTH THE GULF OF TEHUANTEPEC 
AS WELL AS THE GULF OF PAPAGAYO.  HOWEVER...THESE ARE ONLY 
SPORADICALLY PRODUCING 20 KT WINDS WITH SEAS LESS THAN 8 FT...SO 
THESE ARE NOT INCLUDED IN THE HIGH SEAS.

CROSS-EQUATORIAL SOUTHWESTERLY SWELL HAS BREACHED THE S CENTRAL 
BORDER OF THE DISCUSSION AREA WITH 8 FT SEAS IN PLACE S OF 03N 
BETWEEN 115W AND 125W IN SW SWELL.  LITTLE CHANGE IS EXPECTED 
FOR THE NEXT COUPLE OF DAYS.

IF THE GLOBAL MODELS ARE TO BE BELIEVED...THEN THERE WOULD 
APPEAR TO BE LITTLE LIKELIHOOD FOR TROPICAL CYCLOGENESIS WITHIN 
THE NEXT WEEK OR SO IN THE NORTHEASTERN PACIFIC.

$$
LANDSEA