000
AXPZ20 KNHC 010247
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC FRI MAY 01 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0200 UTC. 

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

THE MONSOON TROUGH EXTENDS FROM 09.5N82W TO 08N92W TO LOW PRES 
1007 MB NEAR 08.5N120W TO 07N129W...WHERE IT TRANSITIONS TO 
ITCZ... CONTINUING TO BEYOND 06N140W. SCATTERED TO LOCALLY 
NUMEROUS MODERATE TO STRONG CONVECTION NOTED FROM 02.5S TO 10N E 
OF 85W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 300 
NM EITHER SIDE OF TROUGH BETWEEN 92W AND 105W...AND WITHIN 150 
NM N AND 300 NM S OF TROUGH BETWEEN 111W AND 122W. SCATTERED 
MODERATE TO STRONG CONVECTION NOTED WITHIN 120 NM N AND 150 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 
TONIGHT. 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 98W-
100W. THE WESTERNMOST TROUGH EXTENDS FROM THE NW U.S. TO 28N151W 
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 1035 MB HIGH 
NEAR 38N151W 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 26.5N118W TO 15N140W. 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 IS HOLDING NEAR 
30 KT TONIGHT ACROSS THE GULF N OF 14.5N...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 IS MOVING N-NE ACROSS THE EQUATOR 
AND INTO REGIONAL WATERS TONIGHT...WITH A FIRST MODERATE PULSE  
REACH THE CENTRAL AMERICAN AND MEXICAN COAST BY MORNING...THEN 
THE MAIN PULSE OF STRONG SWELL WITH WAVE PERIODS OF 19-21 
SECONDS ON SAT. THIS SWELL WILL PRODUCING VERY LARGE AND 
DANGEROUS WAVES IN THE COASTAL ZONES FROM PANAMA TO BAJA 
CALIFORNIA...AND WILL ENTER S PORTIONS OF THE GULF OF CALIFORNIA 
SAT AND REACH SOUTHERN CALIFORNIA SAT AFTERNOON AND EVENING.

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STRIPLING