000
AXPZ20 KNHC 172142
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED APR 17 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 07N81W TO 009N90W 05N104W TO 05N120W THEN ITCZ TO
04N140W.  SCATTERED MODERATE TO STRONG CONVECTION WITHIN 240 NM
S OF AXIS E OF 86W AND WITHIN 180 NM N OF AXIS FROM 98W TO 102W.
SCATTERED MODERATE CONVECTION WITHIN 120 NM S OF AXIS FROM 102W
TO 108W.

...DISCUSSION... 
WELL DEFINED UPPER LEVEL CYCLONE AT 29N139W WITH ATTENDANT
TROUGH 00N130W DRIFT NE AS LARGE RIDGE ANCHORED BY ANTICYCLONE
AT 13N109W BLOCKS ITS WAY EAST.  VERY DRY STABLE AIR MASS W OF
TROUGH AXIS WHILE RIDGE ADVECTS ABUNDANT TROPICAL MOISTURE FROM
ITCZ NORTHWARD UNTO BAJA CALIFORNIA PENINSULA.  SECOND UPPER 
LEVEL TROUGH DIGS SW FROM COAST OF GUATEMALA TO 02N98W ALSO KEEPS 
DRY SUBSIDING AIR ALONG ITS AXIS.  WEAK RIDGE ALOFT COAST OF 
COLOMBIA INTRODUCES MOISTURE ALONG MONSOON TROUGH 86W.  

...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
130W 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 THU WITH SEAS BUILDING TO 8 FT.

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

$$
WALLY BARNES