000
AXPZ20 KNHC 112118
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC SAT APR 11 2015

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 
1900 UTC. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              

THE ITCZ AXIS WAS ANALYZED FROM 05N89W TO 01N102W TO 03N112W TO 
02N117W TO 04N130W TO 01N140W. ISOLATED MODERATE CONVECTION WAS 
WITHIN 90 NM SE OF THE AXIS E OF 93W. SCATTERED MODERATE 
CONVECTION WAS WITHIN 150 NM N AND 90 NM S OF THE AXIS BETWEEN 
106W-109W AS WELL AS 180 NM N AND 90 NM S OF THE AXIS BETWEEN 
120W-127W.

...DISCUSSION... 

ENERGY WITHIN A SHARP...POSITIVELY TILTED SOUTHERN STREAM UPPER 
TROUGH FROM NW ARIZONA THROUGH SAN DIEGO CALIFORNIA TO 23N126W 
REFLECTS A 1016 MB LOW PRES SYSTEM AT THE SURFACE NEAR 26N123W. 
A TROUGH EXTENDS NW OF THE LOW TO 31N128W AND A COLD FRONT 
EXTENDS SW OF THE LOW THROUGH 23N124W TO 20N134W. WINDS NEAR 
THIS SYSTEM HAVE DIMINISHED BELOW THE ADVISORY CRITERIA OF 20-25 
KT...BUT THE SEAS CONTINUE TO BE IN THE 8-10 FT RANGE IN NW 
SWELL W OF THE SURFACE BOUNDARY AND N OF 22N. THE SEAS WILL 
SUBSIDE BELOW 8 FT BY SUN MORNING AS THE SURFACE SYSTEM 
DISSIPATES. 

THIS SYSTEM ALOFT WILL SWING INTO NW MEXICO...DRAGGING A MID 
LEVEL TROUGH THROUGH BAJA CALIFORNIA SUR AND THE SOUTHERN GULF 
OF CALIFORNIA LATE TONIGHT THROUGH SUN MORNING. THIS WILL 
ENHANCE THE SURFACE TROUGHING OVER THE REGION AS THE SUBTROPICAL 
RIDGE BUILDS BEHIND THE DISSIPATING SURFACE BOUNDARY OFFSHORE. 
NW TO N WINDS AROUND 20-25 KT WILL BUILD SEAS TO 8 FT JUST SW OF 
THE BAJA CALIFORNIA PENINSULA EARLY SUN. WINDS WILL ALSO PICK UP 
TO ADVISORY CRITERIA IN THE SOUTHERN GULF OF CALIFORNIA BY 
SUNRISE BEFORE DIMINISHING AS THE TROUGH PROGRESSES INLAND. 
CURRENTLY...SCATTERED MODERATE CONVECTION AHEAD OF THE TROUGH 
LIES FROM 25N-29N E OF 117W...INCLUDING OVER THE CENTRAL BAJA 
CALIFORNIA PENINSULA AND THE GULF OF CALIFORNIA. THESE SHOWERS 
AND THUNDERSTORMS SHOULD MAKE THEIR WAY S ALONG THE PENINSULA 
AND SPREAD W INTO NW MAINLAND MEXICO THROUGH THE REMAINDER OF 
THE WEEKEND. 
 
WATER VAPOR IMAGERY SHOWS A SHARP UPPER LEVEL TROUGH EXTENDING 
FROM WESTERN CUBA ACROSS HONDURAS AND NICARAGUA THROUGH A LOW 
NEAR 03N92W TO BEYOND THE GALAPAGOS ISLANDS IN THE SOUTHERN 
HEMISPHERE NEAR 10S95W. THIS RARE CROSS-EQUATORIAL TUTT IS PART 
OF A HIGHLY AMPLIFIED MERIDIONAL FLOW PATTERN BETWEEN 65W AND 
105W IN THE DEEP TROPICS. SPEED DIFFLUENCE ALOFT ON THE E SIDE 
OF THE UPPER LOW IS ENHANCING VERTICAL MOTION AND DEEP 
CONVECTION ALONG THE ITCZ AXIS E OF 93W. THIS CONVECTION IS 
DESCRIBED IN THE SECTION ABOVE.

$$
SCHAUER