000
AXPZ20 KNHC 131541
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN MAY 13 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 
1445 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 09N84W TO 08N92W TO 1009 MB LOW PRES 
AT 10N105W TO 1008 MB LOW PRES AT 08N117W TO 06N120W THEN ITCZ 
02N140W.  SCATTERED MODERATE ISOLATED STRONG S OF TROUGH E OF 
85W.  SCATTERED MODERATE TO STRONG CONVECTION WITHIN 120 NM OF 
TROUGH FROM 102W TO 105W...WITHIN 75 NM OF 09N118W AND WITHIN 
120 NM OF ITCZ FROM 125W TO 133W.   

...DISCUSSION...
ALOFT...WELL-DEFINED DEEP LAYER CYCLONE AT 36N130W MOVING NE 
AWAY FROM FORECAST AREA DRAGS UPPER LEVEL TROUGH FROM 32N126W TO 
20N140W.  VERY DRY SUBSIDING AIR MASS W OF TROUGH AXIS.  BROAD 
DOWNSTREAM RIDGE CREST ALONG 120W DRIVES MOISTURE NE ON ITS W 
SIDE BUT HAS NO SIGNIFICANT UPLIFT MECHANISMS TO PROMPT 
CONVECTION AS LOWER LEVELS ARE DOMINATED BY SURFACE HIGH PRES 
1021 MB AT 27N129W.  SECOND BROAD RIDGE ANCHORED BY ANTICYCLONE 
AT 14N95W PROVIDES MODERATE DIVERGENT OUTFLOW OVER MONSOON 
TROUGH E OF 120W WITH SCATTERED MODERATE TO STRONG DEEP 
CONVECTION CLUSTERED AROUND SURFACE LOW PRES CENTERS.

...AT LOWER LEVELS...TWO LOW PRES CENTERS EMBEDDED IN THE 
MONSOON TROUGH PROMPT SCATTERED TO MODERATE DEEP CONVECTION 
ENHANCED BY WARM SST AND FAVORABLE UPPER LEVEL SUPPORT.  
EASTERNMOST CENTER AT 10N106W MAINTAINS CYCLONIC ORGANIZATION 
BUT HAS FAILED TO TAKE ADVANTAGE OF IT WHILE DRIFTING E-NE INTO 
MORE HOSTILE DRIER ENVIRONMENT.  MODEL GUIDANCE SOLUTION AGREE 
IN BRINGING STRONGER SHEAR ALOFT WITHIN 48 HRS.  

THE WESTERNMOST ONE AT 08N117W HAS ALREADY ENTRAINED DRY AIR AND 
ITS CONVECTION DIMINISHED WITHIN LAST 6 HRS.  BEING FARTHER W IT 
IS LIKELY FEELING STRONGER SHEAR ALREADY AND MAY NOT BE LONG 
BEFORE IT LOSES ANY ORGANIZATION.  

...ELSEWHERE AT THE LOWER LEVELS...
ABOVE MENTIONED HIGH PRES CENTER BRING FRESH NW BREEZE ALONG 
CALIFORNIA W COAST EXTENDING S ALONG BAJA PENINSULA N OF 26N... 
WITH SEAS BARELY REACHING 8 FT THROUGH END OF FORECAST PERIOD.  

WEAK TROUGH OVER BAY OF CAMPECHE FORCE N WINDS ACROSS CHIVELA 
PASS INTO GULF OF TEHUANTEPEC.  WINDS EXPECTED TO REACH 20 TO 30 
KT TONIGHT AND MON BEFORE DIMINISHING LATE TUE. 

FRESH E WINDS OVER GULF OF PAPAGAYO EXPECTED TO DIMINISH MON AS 
WEAK LOW PRES S OF GULF DRIFTS W.

$$
WALLY BARNES