000
AXPZ20 KNHC 130351
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI MAY 13 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
AXIS ALONG 08N105W TO 08N118W TO 06N140W.  ISOLATED MODERATE 
CONVECTION WITHIN 60 NM OF AXIS FROM 117W TO 121W. 

...DISCUSSION...
UPPER LEVEL CYCLONIC VORTEX CENTERED AT 28N126W HAS VERY DRY 
TROUGH AXIS EXTEND SW TO 14N140W.  WEAK 75-80 KT JET CORE SE OF 
AXIS ADVECTS MID/UPPER LEVEL MOISTURE TOWARDS SRN HALF OF BAJA 
CALIFORNIA.  DOWNSTREAM RIDGE ANCHORED BY ANTICYCLONIC GYRE AT 
14N97W ALSO BRINGS ITCZ CONVECTIVE DEBRIS INTO SOUTHERN MEXICO.  
NE DRIFT OF GYRE COMBINED WITH WLY DRIFT OF SURFACE LOW PRES 
1010 MB AT 11N103W HAS EFFECTIVELY DECOUPLED THUS INCREASING ELY 
SHEAR OVER LOW PRES DECREASING CONVECTION SIGNIFICANTLY AND 
WEAKENING SYSTEM AS PREDICTED BY MODEL GUIDANCE.

ELSEWHERE AT THE SURFACE...
WEAK COLD FRONT APPROACH NW CORNER OF BASIN BUT RUN OUT OF 
ENERGY AS UPPER LEVEL SUPPORT SHIFT NE.  RIDGE BUILDS AS FRONT 
DISSIPATES AND TIGHTENS PRES GRADIENT EFFECTIVELY INCREASING NE 
TRADES TO A FRESH BREEZE.  MEANWHILE MODERATE NW WINDS ALONG W 
COAST OF BAJA CALIFORNIA DWINDLED LEAVING 10 FT SWELLS N OF 23N 
E OF 120W FOR NEXT 6 HRS.  

WHILE AFOREMENTIONED LOW PRES 1010 MB AT 11N103W MAINTAINS GOOD 
LOW LEVEL SWIRL...IT REMAINS EMBEDDED IN ITCZ WITH LITTLE OR NO 
ORGANIZATION AND FACING INCREASINGLY ADVERSE UPPER LEVEL 
ENVIRONMENT.  CONVECTION HAS QUICKLY DECREASED AS SYSTEM WEAKEN.

$$
WALLY BARNES