000
AXPZ20 KNHC 302202
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC THU APR 30 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 
2100 UTC. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              

THE MONSOON TROUGH EXTENDS FROM 09N83W TO 10N86W TO LOW PRES 
1008 MB NEAR 09N115W TO 08.5N126W...WHERE IT TRANSITIONS TO 
ITCZ... CONTINUING TO 05N133W TO BEYOND 06N140W. SCATTERED TO 
LOCALLY NUMEROUS MODERATE TO STRONG CONVECTION NOTED FROM 01.5N 
TO 10N E OF 84W. SCATTERED MODERATE TO STRONG CONVECTION NOTED 
WITHIN 270 NM N AND 330 NM S OF TROUGH BETWEEN 85W AND 124W. 
SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 150 NM N 
AND 60 NM S OF ITCZ W OF 132W.

...DISCUSSION...    

A PROGRESSIVE UPPER LEVEL PATTERN DOMINATED BY MAINLY WESTERLY 
WIND FLOW PREVAILS ACROSS MOST OF THE AREA N OF 15N AND W OF 90W 
THIS AFTERNOON. A SERIES OF MIDDLE TO UPPER LEVEL SHORT WAVE 
TROUGHS EMBEDDED IN THIS FLOW ARE PASSING EASTWARD ACROSS THE 
NORTHERN PORTIONS OF THE DISCUSSION AREA. THE EASTERNMOST TROUGH 
IS BROAD AND GENERALLY FLAT AND HAS SHIFTED E ACROSS MEXICO 
ALONG 99W-100W. THE WESTERNMOST TROUGH EXTENDS FROM THE NW U.S. 
TO 29N151W AND IS SINKING SE ACROSS NW PORTIONS OF THE AREA. 
UPPER LEVEL RIDGING GENERALLY PREVAILS S OF 15N ACROSS THE AREA 
AND IS BEING MAINTAINED BY VERY ACTIVE CONVECTION ALONG THE 
MONSOON TROUGH AND ITCZ.

AT THE SURFACE...A BROAD RIDGE EXTENDS SE FROM A 1036 MB HIGH 
NEAR 38N152W TO 19N119W. THE PRESSURE GRADIENT BETWEEN THIS HIGH 
AND LOW PRES ALONG THE ITCZ AND W PORTION OF THE MONSOON TROUGH 
IS PRODUCING FRESH NE TRADEWINDS ACROSS THE ENTIRE REGION W OF 
130W...WHERE MIXED NE AND NW SWELL ARE YIELDING COMBINED SEAS OF 
8 TO 10 FT. THE PRES GRADIENT BETWEEN THE HIGH AND A COASTAL 
TROUGH ACROSS CALIFORNIA IS PRODUCING STRONG TO GALE FORCE 
NORTHERLY WINDS ACROSS THE NEAR AND OFFSHORE WATERS OF 
CALIFORNIA...WHICH IS PRODUCING NORTHERLY SWELL MOVING INTO NE 
PORTIONS OF THE DISCUSSION AREA...WHERE SEAS ARE CURRENTLY 8 TO 
10 FT NW OF A LINE FROM 30N117W TO 27.5N118.5W TO 22N130W. THE 
HIGH WILL SHIFT SLOWLY NE THROUGH SAT AND WEAKEN AND WILL 
MAINTAIN FRESH NE WINDS ACROSS W AND NW PORTIONS. A WEAK COLD 
FRONTAL TROUGH WILL DIP S AND N AND NW PORTIONS AND AID IN 
PRODUCING THE FRESH FLOW NW PORTIONS.  

GULF OF TEHUANTEPEC...STRONG NORTHERLY WIND FLOW DIMINISHED 
BELOW GALE FORCE THIS MORNING AND WAS HOLDING NEAR 30 KT THIS 
AFTERNOON...AND IS EXPECTED TO GRADUALLY DIMINISH TO NEAR 20 KT  
ON FRI AFTERNOON...AND THEN PULSE DURING THE LATE NIGHT FRIDAY 
AND SATURDAY TO 25 TO 30 KT. 

LARGE LONG PERIOD SW SWELL GENERATED FROM A VERY LARGE STORM  
SYSTEM ACROSS THE SE PACIFIC WILL MOVE N-NE INTO REGIONAL WATERS 
TODAY AND REACH THE CENTRAL AMERICAN AND MEXICAN COAST SAT... 
PRODUCING VERY LARGE AND DANGEROUS WAVES IN THE COASTAL ZONES 
FROM PANAMA TO BAJA CALIFORNIA. THIS SWELL WILL ENTER S PORTIONS 
OF THE GULF OF CALIFORNIA SAT AND REACH SOUTHERN CALIFORNIA SAT 
AFTERNOON AND EVENING.

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STRIPLING