000
AXPZ20 KNHC 132148
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI MAY 13 2011

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...
AXIS ALONG 10N104W TO 07N120W TO 06N140W.  ISOLATED MODERATE 
CONVECTION WITHIN 90 NM OF AXIS W OF 110W.

...DISCUSSION...
SHARP UPPER LEVEL TROUGH EXTEND FROM CUTOFF CYCLONIC VORTEX N OF 
AREA THROUGH 32N120W TO 10N133W.  VERY DRY SUBSIDING AIR MASS NW 
OF TROUGH AXIS.  BROAD DOWNSTREAM RIDGE CENTERED IN ANTICYCLONIC 
GYRE AT 14N99W HELP SQUEEZE TROPICAL MOISTURE NE INTO SRN HALF 
OF BAJA CALIFORNIA AND NW MEXICO.  RIDGE ALSO HELPS ADVECT 
ABUNDANT MOISTURE FROM TROPICAL SOUTH AMERICA ALONG MONSOONAL 
TROUGH NEAR 10N WITH SCATTERED MODERATE CONVECTION NOTED S OF 
08N E OF 85W. 

AT THE SURFACE...
WEAK MONSOONAL TROUGH EXTEND FROM WRN PANAMA ALONG 10N TO LOW 
PRES 1010 MB AT 11N102W.  ABUNDANT MOISTURE AVAILABLE E OF 90W 
BUT LACK OF UPLIFT MECHANISMS AND 20-30 KT ELY SHEAR ALOFT IS 
NOT EXACTLY A FAVORABLE ENVIRONMENT FOR DEVELOPMENT.  MODEL 
GUIDANCE DOWNPLAY LOW PRES AND DISSIPATE IT WITHIN 24 HRS.  
  
HIGH PRES 1025 MB N OF 30N REBUILDS AS COLD FRONT DISSIPATED 
AFTER LOSING ALL UPPER LEVEL SUPPORT.  RIDGE EXTEND E-SE TO 
15N115W PROMPTING FRESH TRADES FROM 10N-17N W OF 133W AND 
PRESSING AGAINST BAJA CALIFORNIA W COAST WITHIN NEXT 36-48 HRS.  

MONSOONAL TROUGH STRENGTHENS JUST W OF PANAMA BRINGING A WARM 
AND MOIST FRESH SW FLOW INTO PICTURE LATE IN FORECAST PERIOD.  
WITH SPIN OF VORTICITY AND AVAILABLE MOISTURE...TROPICAL 
CYCLONE SEASON CAN NOT BE FAR AWAY.  

$$
WALLY BARNES