000
AXPZ20 KNHC 121515
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC TUE MAY 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE ITCZ EXTENDS FROM 07N91W TO 05N98W TO 07N111W THEN RESUMES 
FROM 07N113W TO 05N121W TO 07.5N27W THEN RESUMES FROM 07.5N130W 
TO 02N140W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 60 NM 
OF ITCZ BETWEEN 91W AND 95W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 180 NM OF ITCZ BETWEEN 110W AND 
120W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED 
WITHIN 150 NM N OF ITCZ BETWEEN 120W AND 128W. SCATTERED 
MODERATE CONVECTION WAS NOTED WITHIN 90 NM S OF ITCZ BETWEEN 
128W AND 135W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS 
NOTED FROM 00N TO 05N BETWEEN 123W AND 133W. 

...DISCUSSION...

HIGH PRES OF 1034 MB CENTERED NW OF THE AREA NEAR 39N152W 
EXTENDS A RIDGE SE TO NEAR 16N108W. TWO TROUGHS ARE EMBEDDED 
WITHIN THE ITCZ...ONE NEAR 112W AND ONE NEAR 128W. THE PRESSURE 
GRADIENT BETWEEN THE AREA OF HIGH PRESSURE AND THE SURFACE 
TROUGHS ARE PRODUCING FRESH TRADES OVER THE WESTERN WATERS WITH 
SEAS TO 8 FT WITHIN AREA BOUND BY 16N140W TO 08N120W TO 08N140W. 
THERE IS A LOT OF CONVECTION OVER THE WATERS W OF 110W AND S OF 
10N IN RESPONSE TO A KELVIN WAVE PROPAGATING INTO THE REGION. 
FORECAST GUIDANCE SUGGESTS TWO AREAS OF LOW PRESSURE WILL BE 
GENERATED IN THIS AREA OF ACTIVE CONVECTION OVER THE NEXT DAY. 
SEAS WILL SLOWLY SUBSIDE OVER THE NEXT COUPLE OF DAYS WITH ANY 
LINGERING SEAS OF 8 FT OR GREATER WILL BE CONFINED TO NEAR THE 
LOW CIRCULATIONS BY 48 HOURS.

THE PRESSURE GRADIENT BETWEEN THE SURFACE RIDGE AND LOW PRESSURE 
OVER THE SW UNITED STATES ARE PRODUCING FRESH TO STRONG NW-N 
ALONG THE CENTRAL CALIFORNIA COAST. THESE WINDS ARE GENERATING 
FRESH NORTHERLY SWELL WHICH WILL REACH NEAR 30N THROUGH THIS  
AFTERNOON BEFORE SUBSIDING TONIGHT INTO EARLY WED.

LONG PERIOD CROSS EQUATORIAL SOUTHERLY SWELL AT 19-22 SECONDS IS 
PROPAGATING ACROSS THE TROPICAL NE PACIFIC. THE LEADING EDGE IS 
EXPECTED TO REACH CABO CORRIENTES MEXICO AND SURROUNDING AREAS 
AS WELL AS THE SOUTHERN BAJA CALIFORNIA PENINSULA THIS 
AFTERNOON. THIS LONG PERIOD SWELL WILL LEAD TO HAZARDOUS SURF 
AND BEACH CONDITIONS ALONG THE MEXICAN AND CENTRAL AMERICAN 
COASTS LATER TODAY THROUGH WED. SEA HEIGHTS OF 8 FT OR GREATER 
WILL PROPAGATE TO THE NW REACHING AS FAR N AS 06N-07N THROUGH 24 
HOURS BEFORE SUBSIDING BELOW 8 FT N OF THE EQUATOR BY 48 HOURS. 

GULF OF CALIFORNIA...A TIGHT PRES GRADIENT IS FORECAST TO 
DEVELOP ACROSS NW MEXICO BY LATER TODAY WITH FRESH TO STRONG 
SOUTHERLY WINDS DEVELOPING N OF 30N LATE TONIGHT. THE WINDS WILL 
DIMINISH BY SUNRISE WED THEN WILL PULSE AGAIN BY LATE WED NIGHT.

GULF OF PAPAGAYO...WINDS WILL PULSE OVER THE NEXT COUPLE OF DAYS 
OVER THE GULF OF PAPAGAYO. STRONG WINDS WILL PEAK DURING THE 
LATE NIGHT AND EARLY MORNING HOURS THEN DIMINISH SLIGHTLY DURING 
THE DAYTIME AND EARLY EVENING HOURS. ASSOCIATED SEAS WILL BUILD 
TO UP TO 10 FT.

GULF OF TEHUANTEPEC...FRESH TO STRONG NORTHERLY WINDS ARE 
FORECAST LATE TONIGHT DUE TO A LOCALIZED TIGHT PRES GRADIENT 
OVER THE AREA. THESE WINDS WILL BUILD SEAS UP TO 8-10 FT BY 
SUNRISE WED.

$$ 
AL