000
AXPZ20 KNHC 140929
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE APR 14 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0900 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 06N. SCATTERED MODERATE TO ISOLATED 
STRONG CONVECTION EXISTS N OF THE ITCZ AXIS WITHIN 120 NM OF THE 
COAST OF WESTERN PANAMA. SCATTERED MODERATE CONVECTION ALSO 
WITHIN 120 NM N OF ITCZ BETWEEN 120W AND 124W.

...DISCUSSION...

N OF 20N...UPPER PATTERN IS BECOMING MORE AMPLIFIED WITH A 
MID/UPPER TROUGH MOVING EASTWARD THROUGH 128W FOLLOWED BY A 
BUILDING UPPER RIDGE NE OF HAWAII. AT THE SURFACE...A 0230Z 
SCATTEROMETER PASS SHOWED A BROAD SWATH OF 20 TO 30 KT NORTHERLY 
WINDS PUSHING INTO THE WATERS WEST OF NORTHERN BAJA ON THE 
EASTERN PERIPHERY OF 1037 MB SURFACE HIGH WELL NORTH OF THE 
AREA. FOR THE NEXT COUPLE OF DAYS...THE MID/UPPER TROUGH MOVING 
EASTWARD THROUGH 128W IS COMING IN PHASE WITH A LARGER SCALE 
TROUGH DIGGING THROUGH THE PACIFIC NW STATES. THESE FEATURES 
WILL MERGE TONIGHT AND CUTOFF OVER CALIFORNIA...DRIVING A WEAK 
SURFACE FRONT INTO SOUTHERN CALIFORNIA AND THE NORTHERN PART OF 
BAJA LATE TUESDAY INTO WEDNESDAY. SW WINDS AHEAD OF THE FRONT 
WILL INCREASE OVER THE NORTHERN GULF OF CALIFORNIA LATE 
TODAY...THEN DIMINISH THROUGH MIDDAY WED AFTER THE FRONT PASSES 
EAST OF THE AREA. THE 1037 MB SURFACE HIGH PRES WILL FOLLOW 
BEHIND THE FRONT AND SHIFT SOUTHEASTWARD THROUGH LATE WED. WINDS 
WEST OF NORTHERN BAJA WILL GRADUALLY DIMINISH AS THE HIGH PRES 
MOVES CLOSER. MEANWHILE...LONG PERIOD NORTHERLY SWELL WILL 
CONTINUE TO PUSH INTO THE AREA...MAINLY EAST OF 130W.

S OF 20N...AN UPPER ANTICYCLONE REMAINS CENTERED NEAR 
10N128W...WITH WEAKENING UPPER TROUGH TO THE EAST NEAR 120W. 
DIVERGENT FLOW ALOFT BETWEEN THE UPPER ANTICYCLONE AND THE 
TROUGH IS SUPPORTING MODEST CONVECTION ALONG THE ITCZ NEAR 
120W...WHERE A WEAK SURFACE TROUGH IS EVIDENT. FURTHER 
EAST...NOCTURNAL CONVECTION IS NOTED OFF THE COAST OF WESTERN 
PANAMA...NORTH OF THE ITCZ. LIGHT TO MODERATE CROSS-EQUATORIAL 
SOUTHERLY FLOW ALONG WITH ABUNDANT MOISTURE AND WEAK DIVERGENCE 
ALOFT WILL MAINTAIN SCATTERED CLUSTERS CONVECTION BETWEEN THE 
ITCZ AND THE SOUTHERN CENTRAL AMERICAN COAST THROUGH MID WEEK. 
SCATTEROMETER SHOWS A BROAD AREA OF TRADES MAINLY W OF 120W. 
THIS FLOW WILL PERSIST THROUGH THE NEXT COUPLE OF DAYS AS HIGH 
PRES NORTH OF THE AREA SHIFTS SE. MEANWHILE LONG PERIOD NW SWELL 
WILL PUSH INTO THE AREA MAINLY BETWEEN 110W AND 130W...MIXING 
WITH PERSISTENT SW SWELL.

$$
CHRISTENSEN