000
AXPZ20 KNHC 292205
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC MON APR 29 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... 
THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 10N73W TO 05N79W 
TO 10N89W TO 06N102W TO 07N111W...WHERE IT TRANSITIONS TO THE  
INTERTROPICAL CONVERGENCE ZONE...CONTINUING ON TO DEVELOPING LOW 
PRES NEAR 08.5N130W 1010 MB...TO BEYOND 05N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 120 NM S OF 
MONSOON TROUGH BETWEEN 79W AND 97W. SCATTERED MODERATE TO STRONG 
CONVECTION NOTED WITHIN 150 NM EITHER SIDE OF ITCZ BETWEEN 111W 
AND 122W. SCATTERED TO NUMEROUS MODERATE TO STRONG NOTED FROM 
05N TO 10N BETWEEN 123W AND 132W.       

...DISCUSSION...                                                 
AN UPPER LEVEL BLOCKING PATTERN PERSISTS ACROSS THE NE PACIFIC 
THIS AFTERNOON. WATER VAPOR IMAGERY INDICATES A BROAD MIDDLE TO 
UPPER LEVEL CYCLONE CENTERED NEAR 290N139W...AND IS DRIFTING W  
AROUND THE SOUTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE TO 
ITS N ALONG 40N. DRY AIR AND MODERATE TO STRONG SUBSIDENCE 
PREVAILS N OF 20N. A SURFACE RIDGE IS ANCHORED BY A 1031 MB HIGH 
CENTERED NORTH OF THE DISCUSSION AREA NEAR 40N137W. THIS 
CONTINUES TO KEEP CONDITIONS RELATIVELY QUIET FOR THE NEAR TERM 
OVER A MAJORITY OF THE BASIN N OF 15N W OF 110W. LOOKING AHEAD 
ACROSS N PORTIONS OF THE AREA...A WEAK IMPULSE OF MID-LEVEL 
ENERGY IS EXPECTED TO SLIDE SOUTH ALONG THE CALIFORNIA COAST 
WITH SUSTAINED NORTHERLY WINDS SPREADING INTO NE 
PORTIONS...RESULTING IN SEAS BUILDING TO 10 FT BY EARLY 
WEDNESDAY IN THE VICINITY OF 30N126W. SEAS ABOVE 8 FT WILL 
GENERALLY LOCATE N OF 26N BETWEEN 119W AND 133W IN NORTH SWELL 
BY 48 HOURS.

THE REMAINDER OF THE AREA S OF 20N W OF 110W REMAINS FOCUSED ON 
A SURFACE TROUGH EMBEDDED WITHIN THE ITCZ AXIS ANALYZED ALONG 
130W FROM 07N TO 13N...WHERE A RECENT PARTIAL 1822 UTC ASCAT 
PASS SUGGESTED A LOW CENTER DEVELOPING ALONG THE TROUGH NEAR 
08.5N. THE BROAD MIDDLE TO UPPER LEVEL CYCLONE MENTIONED ABOVE 
EXTENDS A TROUGH SE INTO THE TROPICS NEAR 14N140W...WHERE A 
SHORTWAVE TROUGH IS MOVING THROUGH THE BASE. A SHORTWAVE RIDGE 
HAS DEVELOPED NE OR AHEAD OF THIS SHORTWAVE TROUGH...PROVIDING 
DIVERGENCE ALOFT FOR DEEP CONVECTION MENTIONED ABOVE OCCURRING 
ALONG AND E OF THE TROUGH AT 130W. BURSTS OF DEEP CONVECTION IN 
THIS VICINITY TODAY HAVE AIDED IN THE WWD SHIFT OF THE UPPER 
RIDGE ACROSS THIS AREA FROM RECENT DAYS...NOW CENTERED ALONG 
118W AND S OF 24N. THE PRESSURE GRADIENT BETWEEN THE HIGH WELL N 
OF THE AREA AND THE DEVELOPING LOW ALONG THE SURFACE TROUGH IS 
PRODUCING AN AREA OF 20-25 KT NE TO E WINDS ACROSS THE N 
SEMICIRCLE OF THE LOW TO 13N. CONVECTION ACROSS THE AREA WILL 
GRADUALLY WEAKEN ON TUESDAY...WITH THE LOW GRADUALLY COLLAPSING.
 
E OF 110W...RELATIVELY TRANQUIL CONDITIONS ARE NOTED IN 
OBSERVATIONAL DATA...RECENT SCATTEROMETER PASSES...AND LATEST 
GLOBAL MODEL DATA. OF NOTE...STRONG SW SWELL FROM A SOUTHERN 
HEMISPHERE LOW PRESSURE SYSTEM CONTINUES SPREADING NORTHEASTWARD 
REACHING THE MEXICAN AND CENTRAL AMERICAN COAST WITH WAVE 
PERIODS IN THE RANGE OF 15 TO 18 SECONDS. THIS LONG PERIOD SWELL 
EVENT IS EXPECTED TO PERSIST THROUGH LATE THURSDAY.

$$
STRIPLING