000
AXPZ20 KNHC 202201
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                        
2205 UTC SAT APR 20 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
MONSOON TROUGH AXIS FROM 10N85W TO 11N92W TO 06N103W THEN ITCZ 
TO 06N126W.  ITCZ RESUMES FROM 08N131W TO 05N140W.  SCATTERED
MODERATE CONVECTION WITHIN 150 NM S OF AXIS E OF 100W AND W OF
130W.

...DISCUSSION...
WELL DEFINED CYCLONE AT 29N142W STILL UNABLE TO BREAK E DUE TO 
LARGE OMEGA BLOCK ANCHORED BY ANTICYCLONE 14N108W.  WEAKENING
TROUGH ON E SIDE OF BLOCK BREAKS STALEMATE AND ALLOWS CYCLONE TO
SKIRT OVER RIDGE CREST DRAGGING ATTENDANT UPPER LEVEL TROUGH 
ACROSS BASIN N OF 10N AND FORCING ANTICYCLONE EASTWARD.  GFS 
GUIDANCE WEAKENS RIDGE AND SITS IT ALONG 98W BY END OF WEEK...
ALLOWING SEVERAL SHORT WAVES TO MOVE ACROSS NORTHERN LATITUDES
OF BASIN WITH IMPUNITY WHILE RIDGE ADVECTS PLENTY OF TROPICAL
MOISTURE UNTO THE WEST COAST...A RECIPE FOR WET WEATHER. 

...AT THE LOWER LEVELS...
GULF OF TEHUANTEPEC...GALE FORCE WINDS NOTED IN GULF OF
TEHUANTEPEC EARLIER TODAY HAVE DIMINISHED AND WARNING ALLOWED
TO EXPIRE.  STRONG N WINDS EXPECTED TO REACH 20 KT OR LESS BY
LATE SUN.  LINGERING SWELL WILL DRIFT E WHILE SUBSIDING BY MON.
 
GULF OF CALIFORNIA...ONLY FRESH NW WINDS IN THE CENTRAL GULF OF
CALIFORNIA ARE NOTED AND EXPECTED TO BECOME A GENTLE TO MODERATE
BREEZE LATER TODAY.

WEAKENING HIGH PRES CENTER...NOW ONLY 1034 MB...AT 28N137W DRIFT
NW BUT RIDGE EXTEND WELL SE TO 13N100W MAINTAINING DRY AND STABLE
AIR MASS ACROSS LARGE PORTION OF BASIN N OF ITCZ/MONSOON TROUGH.
ABUNDANT CONVECTIVE DEBRIS ADVECTED NE UNTO BAJA CALIFORNIA.

INCREASING WINDS N OF AREA ALONG COAST OF CALIFORNIA BOUND TO 
SWAY 8-9 FT N SWELLS INTO EPAC N OF 28N FROM 122W AND 128W SUN.   
 
...OUTLOOK...
WITH COLLAPSE OF OMEGA BLOCK AND ITS EASTWARD SHIFT...GUIDANCE
POINT TO SEVERAL SHORTWAVES INTRUDING ALONG N LATITUDES WHICH
COULD DETERIORATE WEATHER ALONG COASTAL SECTIONS MIDWAY THROUGH 
LATE IN THE WEEK.

$$
WALLY BARNES