000
AXPZ20 KNHC 181546
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED MAY 18 2011

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.
 
...ITCZ...
AXIS FROM 12N86W TO 05N126W TO 03N140W.  SCATTERED MODERATE 
ISOLATED STRONG CONVECTION WITHIN 240 NM S OF AXIS E OF 110W. 

...DISCUSSION...
UPPER LEVEL TROUGH EXTENDS SW FROM WESTERN ARIZONA TO 30N120W TO 
DEVELOPIING CYCLONIC VORTEX AT 20N140W.  SWATH OF DRY AIR WITHIN 
120 NM OF AXIS.  WIDE BAND OF MOISTURE ROTATE E SEMICIRCLE OF 
CYCLONE...FROM 14N TO 22N W OF 128W.  REMAINDER OF BASIN COVERED 
BY ANTICYCLONIC FLOW AROUND RIDGE ALONG 10N WITH VERY DRY AIR 
MASS N OF 18N.  LOW SHEAR CONDITIONS AND MODERATE DIFFLUENT 
OUTFLOW ALONG RIDGE AXIS ENHANCES DEEP CONVECTION FROM 03N TO 
09N E OF 108W.  ALTHOUGH MODEL GUIDANCE RECOGNIZE SOME INITIAL 
VORTICITY AND FAVORABLE ENVIRONMENT ALOFT...NO SIGNS OF TROPICAL 
ORGANIZATION NOR NO UPLIFTING MECHANISMS ARE NOTED AND GUIDANCE 
EVENTUALLY DISSIPATE LOW LEVEL FEATURES.

...AT THE SURFACE...
BROAD HIGH PRES 1024 MB NW OF BASIN HAS RIDGE EXTEND TO 15N110W 
WITH MINOR DENT PRODUCED BY WEAK COLD FRONT WHICH RUNS FROM 
32N118W TO 27N134W.  FRONT MOVES E OF AREA TONIGHT AND RIDGE 
EXPANDS BRINGING FRESH NW BREEZE ALONG W COAST OF BAJA 
CALIFORNIA.

LARGE BUT SUBSIDING LONG PERIOD CROSS EQUATORIAL SW SWELLS...TO 
11 FT...SPREAD ACROSS MOST OF E PAC THROUGH FORECAST PERIOD. 

$$
WALLY BARNES