000
AXPZ20 KNHC 112144
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED MAY 11 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 06N78W TO 1009 MB LOW PRES AT 09N90W TO 1009 MB LOW 
PRES AT 09N102W TO LOW PRES 1010 MB AT 08N115W TO 03N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 120 NM OF 
AXIS E OF 116W.

...DISCUSSION...
LARGE UPPER LEVEL CYCLONIC VORTEX NEAR FOUR CORNERS IN SW CONUS 
HAS SHARP TROUGH EXTEND TO SECOND VORTEX AT 24N135W.  VERY DRY 
SUBSIDING AIR MASS WITIHN 240 NM OF TROUGH AXIS. TROUGH FLATTENS 
CREST OF DOWNSTREAM RIDGE CENTERED IN ANTICYCLONIC GYRE AT 
08N104W BUT RIDGE DOES NOT MOVE.  GYRE PROVIDES FAVORABLE AREA 
OF DIFFLUENT OUTFLOW AND MINIMAL SHEAR TO SURFACE LOW PRES 1009 
MB AT 09N102W ENHANCING SCATTERED DEEP CONVECTION WITHIN 180 NM 
OF LOW PRES AND ALONG ITCZ.

MODEL GUIDANCE DO NOT FAVOR DEVELOPMENT MAINLY DUE TO BEING
STILL EMBEDDED IN ITCZ.  FORECAST CALLS FOR CONTINUING DEEP 
CONVECTION FOR NEXT 24 HRS BEFORE WINDING DOWN AS IT DRIFT W 
INTO A MORE ADVERSE ENVIRON ALOFT.    

HIGH PRES RIDGE EFFECTIVELY DISSIPATED AS COLD FRONT APPROACHES 
BASIN FROM NW.  WITH RELAXING PRES GRADIENT...PRESENT FRESH NW 
WINDS WITHIN 120 NM OF BAJA CALIFORNIA W COAST WILL DIMINISH 
UNDER 20 KT AND SEAS SUBSIDE UNDER 8 FT WITHIN 12-18 HRS.  

SEVERAL LOW PRES CENTERS ALONG ITCZ DO NOT PRESENT ANY THREAT OF 
ORGANIZATION EVEN WITH FAVORABLE UPPER LEVEL ENVIRONMENT... 
ALTHOUGH DEEP CONVECTION REMAIN PRETTY ACTIVE E OF 116W.  

$$
WALLY BARNES