438  
AXPZ20 KNHC 150351  
TWDEP  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
0405 UTC TUE MAY 15 2018  
 
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  
0215 UTC.  
   
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
 
 
 
THE MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 09N75W TO LOW  
PRESSURE OVER THE FAR SOUTHWESTERN CARIBBEAN AT 11N81W AND  
ACROSS NORTHERN PANAMA TO 09N95W TO 11N106W TO 14N112W TO LOW  
PRESSURE NEAR 12N116W 1010 MB TO 07N123W, WHERE LATEST  
SCATTEROMETER DATA INDICATED THAT IT TRANSITIONS TO THE  
ITCZ TO 04N134W. SCATTERED STRONG CONVECTION IS NOTED WITHIN  
60 NM NORTH OF THE TROUGH BETWEEN 113W AND 115W AND WITHIN 30 NM  
OF THE TROUGH BETWEEN 115W AND 116W. SCATTERED MODERATE TO STRONG  
CONVECTION IS WITHIN 360 NM SOUTH OF THE TROUGH BETWEEN 107W AND  
111W AND WITHIN 180 NM SOUTH OF THE TROUGH BETWEEN 105W AND  
107W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM SOUTH OF THE  
TROUGH BETWEEN 85W AND 88W, ALSO WITHIN 150 NM SOUTH OF THE  
TROUGH BETWEEN 114W AND 117W AND WITHIN 120 NM SOUTH OF THE  
TROUGH BETWEEN 94W AND 99W.  
   
..DISCUSSION
 
 
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  
 
A NW TO SE ORIENTED HIGH PRESSURE RIDGE PREVAILS ACROSS THE  
OFFSHORE WATERS WEST OF BAJA CALIFORNIA, PRODUCING GENTLE TO  
MODERATE NW WINDS OVER THOSE WATERS. THESE WINDS ARE EXPECTED TO  
FRESHEN LATE TONIGHT THROUGH WED, THEN BECOME FRESH TO LOCALLY  
STRONG WED NIGHT AS THE RIDGE STRENGTHENS SLIGHTLY. ALTIMETER  
DATA FROM THIS EVENING INDICATED THAT SEAS WERE JUST BELOW 8 FT,  
IN THE 5-7 FT RANGE. THEY WILL CHANGE LITTLE THROUGH LATE TUE  
BEFORE BUILDING SLIGHTLY ON WED TO 6-8 FT IN MIXED SW SWELL WITH  
FRESH NNW WIND SWELL.  
 
THE GRADIENT OFFSHORE BAJA CALIFORNIA WILL TIGHTEN MORE THAN  
WHAT IT HAS BEEN DURING THE PAST SEVERAL DAYS AS THE ABOVE  
MENTIONED RIDGE STRENGTHENS. THIS WILL LEAD TO NW WINDS OFFSHORE  
MOST OF THE PENINSULA TO INCREASE TO STRONG SPEEDS BEGINNING  
LATE WED AFTERNOON OR EVENING, WITH SEAS REMAINING AT 6-8 FT.  
MODEL GUIDANCE INDICATES THAT THESE WINDS WILL CONTINUE THROUGH  
THU NIGHT.  
 
GULF OF CALIFORNIA: S TO SW WINDS OF AROUND 15-20 KT OVER A  
SMALL SECTION OF THE NORTHERN GULF OF CALIFORNIA FROM 30N TO  
30.5N W OF 113W WILL BECOME LIGHT AND VARIABLE TUE. GENTLE TO  
MODERATE NW WINDS WILL CONTINUE ACROSS THE REMAINDER OF THE GULF  
THROUGH WED, EXCEPT FOR FRESH NW WINDS ALONG THE MEXICO COAST  
FROM 24N TO 26N TUE EVENING THROUGH WED EVENING.  
 
GULF OF TEHUANTEPEC: WINDS HAVE BECOME LIGHT TO GENTLE S TO SW IN  
DIRECTION. WINDS WILL AGAIN BECOME MODERATE TO FRESH FROM THE  
N AND NE LATE THIS AFTERNOON AND THROUGH TONIGHT, BUT BRIEFLY  
BEFORE THEY BECOME GENTLE S TO SW WINDS ON WED. THIS CYCLE OF  
CHANGING WINDS WILL CONTINUE THROUGH THU AS A WEAK PRESSURE  
PATTERN REMAINS OVER MEXICO.  
 
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND  
WITHIN 750 NM OF ECUADOR...  
 
GULF OF PAPAGAYO: LIGHT TO GENTLE WINDS WILL DOMINATE THE GULF  
MOST OF THE FORECAST PERIOD WITH SEAS OF 5-6 FT DIMINISHING  
SLIGHTLY ON TUE TO 4-5 FT IN LONG PERIOD SW SWELL. A STRONG PULSE  
OF CROSS EQUATORIAL SW SWELL WILL MOVE INTO THE REGIONAL WATERS  
BEGINNING WED, AND BUILD SEAS TO 5-7 FT THU THROUGH SAT.  
 
GULF OF PANAMA: GENTLE TO MODERATE S TO SW WINDS ARE FORECAST  
DURING THE NEXT SEVERAL DAYS, WITH SEAS OF 4-6 FT IN LONG PERIOD  
SOUTHERLY SWELL, BUILDING TO 5-7 FT WED NIGHT THROUGH SAT AS  
LONG PERIOD SW SWELL REACHES THE COASTS OF PANAMA AND COLOMBIA.  
 
ELSEWHERE, GENTLE TO MODERATE SOUTHWEST WINDS ARE EXPECTED TO  
THE SOUTH OF THE MONSOON TROUGH WITH AXIS ROUGHLY ALONG 09N/10N,  
WITH LIGHT TO GENTLE VARIABLE WINDS NORTH OF TROUGH. SEAS ARE  
FORECAST TO BUILD TO 6-7 FT IN LONG PERIOD SW SWELL BETWEEN  
ECUADOR AND THE GALAPAGOS ISLANDS BEGINNING ON WED.  
 
REMAINDER OF THE AREA...  
 
A RIDGE EXTENDS FROM THE NW WATERS SOUTHEASTWARD TO NEAR THE  
REVILLAGIGEDO ISLANDS. THE PRESSURE GRADIENT BETWEEN THE RIDGE  
AND THE MONSOON TROUGH AND ITCZ TO THE SOUTH IS PRESENTLY WEAK,  
AND YIELDING MODERATE NE-E TRADE WINDS BETWEEN ABOUT 10N AND 22N  
TO THE WEST OF 110W. SEAS ACROSS THIS TRADEWIND BELT ARE  
EXPECTED 7-9 FT THIS AFTERNOON AND WILL SUBSIDE TO 6-8 FT TONIGHT  
THROUGH WED. THE RIDGE WILL SHIFT SLIGHTLY SE THROUGH WED AND  
INCREASE WINDS ACROSS THE TRADEWIND BELT EVER SO SLIGHTLY BEFORE  
NEW HIGH PRESSURE SHIFTS SE INTO N PORTIONS OF THE DISCUSSION  
AREA THU AND INCREASES TRADE WINDS TO FRESH TO STRONG. SEAS ARE  
EXPECTED TO INCREASE TO 7-9 FT THU INTO FRI.  
 
DECAYING NW SWELL IS PROPAGATING THROUGH THE WATERS NORTH OF 20N  
BETWEEN BAJA CALIFORNIA AND 120W, WHERE SEAS ARE PEAKING AT 7-8  
FT. THESE SEAS WILL SUBSIDE TO LESS THAN 8 FT LATE TONIGHT AND  
CHANGE LITTLE THROUGH THU.  
 

 
AGUIRRE  
 
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