000
AXPZ20 KNHC 222205
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN JUL 22 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 
2030 UTC.

...SPECIAL FEATURES...
A 1008 MB LOW PRESSURE EMBEDDED IN THE MONSOON TROUGH NEAR 
10N110W IS THE RESULT OF THE INTERACTION OF A TROPICAL WAVE 
EXTENDING FROM 15N108W TO LOW CENTER AND THE MONSOON TROUGH. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS PRESENT WITHIN 
180 NM E SEMICIRCLE OF THE LOW AND SCATTERED MODERATE EXISTS 
WITHIN 120 NM W SEMICIRCLE OF THE LOW.  EASTERLY VERTICAL SHEAR 
SHOULD REMAIN WEAK TO MODERATE...SEA SURFACE TEMPERATURES VERY 
WARM...AND LOWER LEVEL MOISTURE QUITE ABUNDANT DURING THE NEXT 
COUPLE OF DAYS.  THUS ENVIRONMENTAL CONDITIONS ARE BECOMING MORE 
CONDUCIVE FOR A TROPICAL DEPRESSION TO FORM AND THE SYSTEM HAS 
NOW A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 
48 HOURS.

...TROPICAL WAVES...
ANOTHER TROPICAL WAVE EXTENDS FROM 14N93W TO A 1009 MB LOW PRES 
ALSO EMBEDDED IN THE MONSOON TROUGH NEAR 09N94W. THE WAVE IS 
EMBEDDED WITHIN A LARGE AREA OF MOISTURE AS DEPICTED ON THE TPW 
ANIMATION. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION 
EXISTS WITHIN 180 NM OF THE MONSOON TROUGH AXIS...THOUGH NO 
COHERENT CONVECTION IS DIRECTLY ASSOCIATED WITH THE LOW AS OF 
YET.  THE WAVE IS EQUATORWARD OF A RATHER LARGE TROPICAL UPPER 
TROPOSPHERIC TROUGH CENTERED OVER CENTRAL AMERICA.  THIS UPPER 
LOW HAS BEEN PRODUCING MODERATE WESTERLY VERTICAL SHEAR OVER THE 
WEAK LOW.  THE GLOBAL MODELS SUGGEST THAT THIS SHEAR SHOULD 
WEAKEN AND BE REPLACED BY WEAK TO MODERATE EASTERLY SHEAR.  
CORRESPONDINGLY...SOME TROPICAL DEVELOPMENT IS SEEN IN ALL OF 
THE GLOBAL MODELS THOUGH NONE RAPIDLY INDICATE GENESIS AND 
INTENSIFICATION AS A TROPICAL CYCLONE IN THE NEXT TWO DAYS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 07N77W TO A 1009 MB LOW 
PRES NEAR 09N94W TO 12N108W.  THE TROUGH AXIS BEGINS AGAIN AT 
07N111W AND EXTENDS TO 09N130W THEN ITCZ TO BEYOND 10N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION EXISTS WITHIN 180 
NM OF MONSOON TROUGH AXIS E OF 102W.

...DISCUSSION...
1031 MB HIGH PRESSURE CENTERED NW OF THE FORECAST AREA NEAR 
40N143W EXTENDS A RIDGE SE TO NEAR 25N120W. THE PRESSURE 
GRADIENT BETWEEN THIS FEATURE AND LOWER PRES ALONG THE MONSOON 
TROUGH AND IN THE VICINITY OF THE ITCZ IS MAINTAINING FRESH 20 
KT TRADE WINDS FROM 10N TO 18N W OF 125W AS DEPICTED BY THE 
1838Z ASCAT SCATTEROMETER PASSES. THIS AREA OF TRADES WILL 
CONTINUE THROUGH THE FORECAST PERIOD BUT WILL SHRINK W IN ABOUT 
48 HOURS. THE HIGH PRES IS FORECAST TO STRENGTHEN N OF THE AREA 
BY MON. AS A RESULT...SEAS GENERATED BY STRONG TO NEAR GALE 
FORCE WINDS JUST OFF THE CALIFORNIA COAST WILL REACH THE NE 
WATERS. 

CROSS EQUATORIAL LONG PERIOD SW SWELLS OF 17-19 SECONDS ARE 
CURRENTLY IMPACTING THE COAST OF MEXICO...CENTRAL AMERICA AND 
BAJA CALIFORNIA...INCLUDING THE FAR S PORTION OF THE SEA OF 
CORTEZ. THE POTENTIAL FOR LARGE BREAKING WAVES AND DANGEROUS RIP 
CURRENTS WILL SLOWLY DIMINISH THROUGH MONDAY AS THE SWELL TRAIN 
SUBSIDES. 

WEAK E GULF OF PAPAGAYO AND NE GULF OF TEHUANTEPEC GAP WIND 
EVENTS ARE OCCURRING...BUT REMAIN AT OR BELOW 20 KT FOR THE NEXT 
COUPLE OF DAYS.  THUS THESE ARE NOT INCLUDED WITHIN THE HIGH 
SEAS FORECASTS.  

$$
LANDSEA