686  
AXPZ20 KNHC 140952  
TWDEP  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
1005 UTC MON MAY 14 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH  
0930 UTC.  
   
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
 
 
 
THE MONSOON TROUGH AXIS EXTENDS FROM NORTHWEST COLOMBIA TO 08N79W  
TO 07N93W TO 08N100W, AND NORTHWESTWARD FROM THERE TO A 1010 MB  
LOW AT 12N115W. IT CONTINUES TO 05N120W TO 05N130W, WHERE LATEST  
SCATTEROMETER DATA INDICATED IT TRANSITIONS TO THE ITCZ AXIS TO  
BEYOND THE AREA AT 06N140W. SCATTERED MODERATE MODERATE ISOLATED  
STRONG CONVECTION IS SEEN WITHIN 180 NM SOUTH OF THE AXIS  
BETWEEN 100W AND 106W, AND WITHIN 120 NM SOUTHEAST OF THE AXIS  
BETWEEN 116W AND 120W. SCATTERED MODERATE CONVECTION IS WITHIN  
180 NM NORTH AND 120 NM SOUTH OF THE AXIS BETWEEN 84W AND 88W.  
   
..DISCUSSION
 
 
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  
 
A NW TO SE ORIENTED HIGH PRESSURE RIDGE IS PRESENT ACROSS THE  
OFFSHORE WATERS WEST OF BAJA CALIFORNIA. IT IS BRINGING GENTLE TO  
MODERATE NORTHWEST WINDS OVER THOSE WATERS. THESE WINDS WILL  
CONTINUE THROUGH THIS AFTERNOON, THEN INCREASE TO FRESH SPEEDS  
BEGINNING TONIGHT THROUGH WED AND TO FRESH TO LOCALLY STRONG  
SPEEDS WED NIGHT AS THE RIDGE STRENGTHENS SLIGHTLY, AND WHILE AT  
THE SAME TIME IT BEGINS TO BUILD EAST-SOUTHEASTWARD. THESE WINDS  
ARE FORECAST TO INCREASE A LITTLE MORE TO FRESH TO LOCALLY  
STRONG ON WED NIGHT. SEAS WILL BE IN THE 5-7 FT RANGE THROUGH  
EARLY WED AND BUILD TO 6-8 FT IN A SW TO W SWELL AFTERWARDS OVER  
MOST OF THE OFFSHORE WATERS, HOWEVER, SEAS ARE IN THE 6-8 FT  
RANGE IN A NW SWELL OVER THE OFFSHORE WATERS BETWEEN 114W AND  
118W FROM THE LOCATIONS OF PUNTA EUGENIA TO SAN LAZARO.  
 
GULF OF CALIFORNIA: S TO SW WINDS OF 15-20 KT ARE OVER THE  
NORTHERN SECTOR OF THE GULF OF CALIFORNIA FROM 30N TO 31N WEST OF  
114W. THESE WINDS BECOME LIGHT AND VARIABLE TONIGHT. GENTLE TO  
MODERATE NW WINDS WILL CONTINUE ACROSS THE REMAINDER OF THE GULF  
THROUGH WED, EXCEPT FOR A BRIEF INSTANCE OF FRESH TO STRONG  
NORTHWEST WINDS NEAR AND ALONG THE COAST OF MEXICO FROM 24N TO  
26N ON TUE NIGHT.  
 
GULF OF TEHUANTEPEC: WINDS WILL BRIEFLY BECOME NORTHWEST TO  
NORTH TO MODERATE TO FRESH SPEEDS THIS MORNING TILL EARLY  
AFTERNOON, THEN BECOME SW TO W AT GENTLE TO MODERATE SPEEDS  
TONIGHT. WINDS WILL AGAIN BRIEFLY BECOME NW TO N AT MODERATE TO  
FRESH SPEEDS ON TUE MORNING TILL THE EARLY AFTERNOON HOURS.  
 
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 4-6 FT IN LONG PERIOD  
SW SWELL, BUILDING TO 5-7 FT WED NIGHT AS ANOTHER SET OF LONG  
PERIOD SW SWELL REACHES THE COAST OF CENTRAL AMERICA.  
 
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 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 8N, 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 TUE.  
 
OVERNIGHT NUMEROUS STRONG CONVECTION THAT FORMED OVER THE  
WESTERN HALF OF NICARAGUA AND OVER SOUTHEASTERN EL SALVADOR HAS  
MOVED OFFSHORE, AND IS LOCATED FROM 10N TO 13N TO THE E OF 89W TO  
JUST INLAND OF THESE LOCATIONS. THIS ACTIVITY IS MOVING  
SOUTHWESTWARD UNDER UPPER NORTHERLY FLOW FOUND ON THE EASTERN  
PERIPHERY OF AN UPPER-LEVEL ANTICYCLONE CENTERED NEAR 16N100W.  
 
REMAINDER OF THE AREA...  
 
A RIDGE EXTENDS FROM THE NW SOUTHEASTWARD TO NEAR THE REVILLAGIGEDO  
ISLANDS. LOW PRESSURE, REMNANTS OF RECENT TROPICAL DEPRESSION  
ONE-E, IS NEARLY STATIONARY NEAR 13N130W WITH A CENTRAL PRESSURE  
OF 1012 MB. THE SMALL CYCLONIC CIRCULATION OF THE LOW IS CLEARLY  
EXPOSED AND BECOMING ILL-DEFINED WITH TIME. MODERATE TO FRESH  
NORTH TO NORTHEAST WINDS ARE WITHIN 240 NM OF THE LOW IN THE NW  
QUADRANT AND 180 NM IN THE NE QUADRANT. A SWIRL OF LOW-CLOUDS  
AROUND THE CENTER IS EVIDENT ON SATELLITE IMAGERY OVER THE AREA  
FROM 11N TO 16N BETWEEN 128W AND 133W. ISOLATED SHOWERS ARE  
POSSIBLE WITH THESE CLOUDS. THE LOW IS FORECAST TO WEAKEN TO A  
TROUGH LATE ON TUE AS IT DRIFTS SOUTHWARD, AND WHILE AT THE SAME  
TIME THE HIGH PRESSURE TO ITS NORTH BEGINS TO BUILD SOUTHWARD.  
 
DECAYING NW SWELL IS PROPAGATING THROUGH THE WATERS FROM 22N TO  
26N BETWEEN 114W AND 128W, WHERE SEAS ARE PEAKING TO 8 FT. AS THE  
SWELL ENERGY CONTINUES TO DISSIPATE, EXPECT THESE SEAS TO  
SUBSIDE TO LESS THAN 8 FT BY LATE TONIGHT.  
 
SEAS TO 8 FT INDUCED MAINLY BY SW TO W SWELL, COMBINING TO  
SOME EXTENT WITH NE WIND WAVES ARE PRESENT FROM 13N TO 20N  
BETWEEN 113W AND 130W. AN OVERNIGHT ALTIMETER PASS CAPTURED SOME  
OF THE VALUES OF 8 FT. SEAS TO 8 FT IN MIXED SW AND NW SWELL ARE  
WITHIN THE AREA FROM 13N TO 20N BETWEEN 130W AND 134W. THESE  
AREAS WILL GRADUALLY SHIFT WESTWARD THROUGH WED WHILE SHRINKING  
IN COVERAGE.  
 
AS PREVIOUSLY MENTIONED, A 1010 MB LOW REMAINS EMBEDDED WITHIN  
THE MONSOON THROUGH NEAR 12N115W. THE LOW IS AT THE BASE OF BROAD  
NE TO SW ALIGNED CYCLONIC CIRCULATION THAT COVERS THE AREA FROM  
ROUGHLY 10N TO 17N AND BETWEEN 109W AND 120W. DEEP CONVECTION IS  
REMOVED FROM THE CENTER OF THE LOW, AND IS IDENTIFIED AS THE  
SCATTERED STRONG TYPE WITHIN 120 NM OF THE LOW IN THE SE  
QUADRANT. SCATTERED MODERATE CONVECTION IS NE OF THE LOW FROM  
14N TO 17N BETWEEN 107W AND 111W, AND ALSO WITHIN 30 NM OF  
15N114W. THE MAJORITY OF THIS ACTIVITY IS UNDERNEATH THE WESTERN  
PERIPHERY OF A MID TO UPPER-LEVEL RIDGE THAT EXTENDS FROM THE  
ANTICYCLONE MENTIONED EARLIER THAT IS NEAR 16N100W WEST-  
SOUTHWESTWARD TO NEAR 14N111W WHERE IT IS INTERRUPTED BY A MID TO  
UPPER-LEVEL TROUGH THAT STRETCHES FROM EAST OF THE REMAINDER  
AREA NEAR 21N111W TO 13N115W. STRONG SOUTHWEST WINDS AHEAD OF  
THIS TROUGH ARE KEEPING THE DEEP CONVECTIVE ACTIVITY DISPLACED TO  
THE NORTHEAST OF THE LOW, FOR THE TIME BEING. ACCORDING TO THE  
GLOBAL MODELS, THE LOW SHOULD PERSIST OVER THE NEXT 48 TO 72  
HOURS AS IT TRACKS IN A GENERAL WEST TO WEST- SOUTHWEST DIRECTION  
UNDER THE SOUTHERN PERIPHERY OF BUILDING HIGH PRESSURE.  
 

 
AGUIRRE  
 
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