000
AXPZ20 KNHC 180303
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU APR 18 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH 09N84W TO 05N107W TO 06N115W THEN ITCZ TO
07N120W TO 03N140W.  SCATTERED MODERATE TO STRONG CONVECTION 
WITHIN 240 NM S OF AXIS E OF 87W AND WITHIN 180 NM OF AXIS FROM
89W TO 102W.  SCATTERED MODERATE CONVECTION WITHIN 90 NM S OF
AXIS FROM 106W TO 113W.

...DISCUSSION... 
WELL DEFINED UPPER LEVEL CYCLONE AT 29N139W WITH ATTENDANT
TROUGH TO 00N128W DRIFT NE AS LARGE RIDGE ANCHORED BY ANTICYCLONE
AT 13N109W BLOCKS ITS PATH EAST.  VERY DRY STABLE AIR MASS W OF
TROUGH AXIS WHILE RIDGE ADVECTS ABUNDANT TROPICAL MOISTURE FROM
ITCZ NORTHWARD UNTO BAJA CALIFORNIA PENINSULA.  RIDGE PROMPTS
MODERATE DIVERGENT FLOW WITH WITH DOWNSTREAM TROUGH ENHANCING
SCATTERED MODERATE TO STRONG CONVECTION ALONG MONSOON TROUGH FROM
98W TO 102W.  DOWNSTREAM UPPER LEVEL TROUGH DIGS SW FROM COAST OF
GUATEMALA TO 02N96W ALSO KEEPS DRY SUBSIDING AIR ALONG ITS AXIS.
WEAK RIDGE ALOFT COAST OF COLOMBIA INTRODUCES MOISTURE ALONG
MONSOON TROUGH 87W.  

...ELSEWHERE AT LOWER LEVELS...
SURFACE RIDGE WITH HIGH PRES CENTER 1037 MB AT 39N135W MAINTAINS
STABLE CONDITIONS ACROSS MOST OF BASIN N OF 10N...WHILE BRINGING
MODERATE TO FRESH NW BREEZE ALONG COAST OF CALIFORNIA WITH SEAS 
TO 12 FT.  MODERATE TO FRESH NE TRADE WINDS FROM 10N TO 20N W OF
120W EXPECTED TO DIMINISH AS HIGH PRES CENTER DRIFTS E.  ON THE
OTHER HAND...THIS SHOULD ALSO INCREASE NW WINDS INSIDE GULF OF 
CALIFORNIA TO A STRONG BREEZE BY LATE THU WITH SEAS BUILDING TO
8 FT BY FRI.

...OUTLOOK...
GULF OF CALIFORNIA WINDS DIMINISH TO GENTLE TO MODERATE BREEZE
BY SUN AS HIGH PRES CONTINUES ITS NE MOVE...WHILE N WINDS OVER
GULF OF TEHUANTEPEC ARE EXPECTED TO INCREASE SAT. 

$$
WALLY BARNES