000
AXPZ20 KNHC 301519
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC TUE APR 30 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1300 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...             
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 08N77W TO 06N81W TO 
10N89W TO 07N120W. THE ITCZ AXIS WAS ANALYZED FROM 07N120W TO 
08N126W TO 1008 MB LOW PRES NEAR 07N128W AND A SECOND 1008 MB 
LOW PRES NEAR 09N134W THEN ITCZ CONTINUES FROM 07N135W TO 
05N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 240 NM SE OF 
THE AXIS BETWEEN 91W AND 95W AS WELL AS WITHIN 210 NM N OF THE 
AXIS BETWEEN 109W AND 118W IN ADDITION TO WITHIN 210 NM N OF THE 
AXIS BETWEEN 120W AND 124W. ISOLATED MODERATE CONVECTION WAS 
WITHIN 90 NM EITHER SIDE OF A LINE FROM 15N97W TO 04N100W AS 
WELL AS FROM 05N TO 13N BETWEEN 127W AND 132W. 
  
...DISCUSSION...                                                 
AN UPPER LEVEL RIDGE AXIS EXTENDING FROM 06N135W TO AN 
ANTICYCLONE NEAR 10N110W THROUGH 12N103W TO 08N98W WHERE IT IS 
DISRUPTED BY AN UPPER TROUGH AND THEN CONTINUES FROM 08N93W TO 
EASTERN PANAMA NEAR 08N77W LIES NEAR THE ITCZ/MONSOON TROUGH. 
STRONGLY DIVERGENT FLOW CAN BE FOUND W OF THE ANTICYCLONE WHERE 
CONVECTION AND AVAILABLE LOW- TO MID-LEVEL MOISTURE ARE MOST 
PREVALENT. THIS CONVECTION IS DESCRIBED IN THE SECTION ABOVE. 
OUTFLOW FROM THIS CONVECTION IS BEING DIRECTED NORTHEASTWARD 
INTO THE SW SIDE OF THE 90-KT UPPER JET CENTERED ALONG 22N. AN 
UPPER LOW LIES NW OF THE JET NEAR 28N137W. THIS LOW EXTENDS 
TROUGHS EASTWARD INTO THE NORTHERN BAJA CALIFORNIA PENINSULA AND 
SOUTHWARD TO 10N140W. TWO AREAS OF 1008 MB LOW PRES AT THE 
SURFACE WERE NOTED VIA SATELLITE IMAGERY ALONG THE ITCZ AXIS 
NEAR 07N128W AND 09N134W. THE 0630 UTC JASON-1 PASS SHOWED SEAS 
TO 9 FT NEAR THESE LOWS. CONVECTION NEAR THESE LOWS HAS WANED 
OVER THE LAST 12 HOURS AND THE LOW CENTERS ARE EXPECTED TO 
DISSIPATE AT THE SURFACE OVER THE NEXT 24 HOURS OR SO. THE OTHER 
AREA OF PREVALENT CONVECTION LIES BETWEEN 90W AND 100W NEAR THE 
DEEP LAYER TROUGH THAT INTERRUPTS THE UPPER RIDGE AXIS. THIS 
CONVECTION IS ALSO DESCRIBED IN THE SECTION ABOVE. THE ENTIRE 
UPPER PATTERN IS EXPECTED TO SHIFT APPROXIMATELY 5 DEGREES TO 
THE E OVER THE NEXT TWO DAYS.

THE 1032 MB SURFACE HIGH LIES WELL N OF THE AREA NEAR 46N136W 
AND EXTENDS A RIDGE AXIS THROUGH 25N133W TO 18N115W. THE 0530 
UTC ASCAT PASS SHOWS MODERATE TO FRESH TRADE WINDS OVER THE 
FORECAST AREA. STRONG N WINDS ON THE E SIDE OF THE HIGH LIE OFF 
THE CALIFORNIA COAST N OF SANTA BARBARA AND ARE PROPAGATING N 
SWELL WITH SEAS OVER 8 FT FOUND JUST S OF 30N. THE STRONG N 
WINDS AND NORTHERLY SWELL WILL EXPAND WESTWARD OVER THE NEXT FEW 
DAYS...WITH 8-10 FT SEAS FOUND N OF 15N BETWEEN 119W-138W BY THU 
MORNING. 

$$
SCHAUER