000
AXPZ20 KNHC 221532
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.

...SPECIAL FEATURES...
A 1008 MB LOW PRESSURE EMBEDDED IN THE MONSOON TROUGH NEAR 
10N109W IS THE RESULT OF THE INTERACTION OF A TROPICAL WAVE 
EXTENDING FROM 15N108W TO LOW CENTER AND THE MONSOON TROUGH. THE 
LOW IS CURRENTLY PRODUCING WIDESPREAD CLOUDINESS AND SCATTERED 
THUNDERSTORMS...WITH A CLUSTER OF MODERATE TO STRONG CONVECTION 
WITHIN 180 NM E QUADRANT OF LOW CENTER...AND ANOTHER CLUSTER OF 
MODERATE TO ISOLATED STRONG CONVECTION WITHIN 210 NM W QUADRANT 
OF LOW CENTER. THE FIRST ONE IS ASSOCIATED WITH A DEVELOPING 
BAND TO THE E TRYING TO WRAPPER AROUND THE LOW CENTER. 
UPPER-LEVEL WINDS AND OTHER ENVIRONMENTAL CONDITIONS ARE 
BECOMING MORE CONDUCIVE FOR A TROPICAL DEPRESSION TO FORM DURING 
THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS NOW A HIGH CHANCE OF 
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

...TROPICAL WAVES...
ANOTHER TROPICAL WAVE EXTENDS FROM 14N92W 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 
MIMIC/TPW ANIMATION. SCATTERED SHOWERS AND ISOLATED TSTMS ARE 
NOTED E OF THE WAVE AXIS. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS NEAR THE LOW CENTER MAINLY TO THE SW QUADRANT. THE 
WAVE WILL MOVE WWD IN TANDEM WITH THE LOW CENTER.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 08N78W TO A 1009 MB LOW 
PRES NEAR 08N95W TO 12N104W TO A 1008 MB LOW NEAR 10N109W TO 
08N120W TO 09N130W THEN ITCZ TO BEYOND 08N140W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM S 
OF MONSOON TROUGH AXIS E OF 91W...AND WITHIN 90 NM N OF TROUGH 
AXIS BETWEEN 86W AND 91W. SIMILAR CONVECTION IS FROM 06N TO 10N 
BETWEEN 95W AND 101W...AND WITHIN 150 NM N OF TROUGH AXIS FROM 
100W TO 103W. CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION 
FROM 04N TO 06N BETWEEN 84W AND 88W. 

...DISCUSSION...
1031 MB HIGH PRESSURE CENTERED NW OF THE FORECAST AREA NEAR 
41N144W EXTENDS A RIDGE SE TO NEAR 20N115W. 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 120W AS DEPICTED BY THE MOST 
RECENT 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 THE REMAINDER OF THE 
WEEKEND AS THE SWELL TRAIN SUBSIDES. 

FRESH GAP WINDS OF 20 KT CONTINUE ACROSS THE GULF OF PAPAGAYO. 
THE FORECAST CALLS FOR WINDS TO BECOME MORE DIURNALLY FORCED 
WITH 20 KT WINDS ONLY POSSIBLE DURING THE OVERNIGHT AND EARLY 
MORNING HOURS WITH THE AID OF THE DRAINAGE FLOW. AN EARLIER 
ASCAT PASS PROVIDED OBSERVATIONS OF THESE WIND SPEEDS.

FRESH GAP WINDS OF 20 KT ARE FUNNELING INTO THE GULF OF 
TEHUANTEPEC BASED ON FEW SHIP OBSERVATIONS AND THE LATEST 
WINDSAT PASS. THIS WEATHER PATTERN IS FORECAST TO PERSIST 
THROUGH EARLY TUE MORNING.  

$$
GR