709  
AXPZ20 KNHC 230945  
TWDEP  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
1005 UTC THU NOV 23 2017  
 
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  
0945 UTC.  
   
..SPECIAL FEATURE
 
 
GULF OF TEHUANTEPEC GALE WARNING: 30 TO 40 KT GALE FORCE WINDS  
WILL CONTINUE INTO EARLY THU AFTERNOON WITH MINIMAL GALE  
CONDITIONS THEN PERSISTING THROUGH MID MORNING ON FRI. WINDS  
WILL DIMINISH TO 20 KT OR LESS LATE SAT MORNING. EXPECT MAX SEAS  
OF 17 FT NEAR 14N96W TONIGHT. THE RESULTANT NE SWELL WILL  
PROPAGATE SW, MIXING WITH LONG- PERIOD CROSS EQUATORIAL SWELL,  
WITH SEAS 8 FT OR HIGHER WELL DOWNSTREAM OF THE GULF OF  
TEHUANTEPEC ALONG 08N BETWEEN 95W AND 105W ON FRI NIGHT BEFORE  
BEGINNING TO SUBSIDE. EXPECT WINDS 20 KT OR LESS AND SEAS LESS  
THAN 8 FT ONLY BRIEFLY ON SAT AFTERNOON. STRONG N WINDS ARE  
FORECAST TO RESUME AGAIN ON SAT EVENING WITH GALE CONDITIONS  
JUST AFTER SUNRISE ON SUN. LATEST GUIDANCE IS SUGGESTING ANOTHER  
30 TO 40 KT EVENT ON SUN NIGHT WITH THE GALES DIMINISHING LATE  
MON.  
 
INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...  
 
THE MONSOON TROUGH EXTENDS W BETWEEN 09N AND 11N ACROSS THE SW  
CARIBBEAN TO THE PACIFIC COAST OF COSTA RICA AT 09N84W, AND  
CONTINUES W TO 09N105W WHERE SCATTEROMETER WINDS INDICATE A  
TRANSITION TO AN ITCZ, WHICH CONTINUES NW TO AN EMBEDDED TROUGH  
AT 12N114W, THEN THE ITCZ TURNS SW TO BEYOND 07N140W. ISOLATED  
MODERATE TO STRONG CONVECTION IS NOTED WITHIN 90 NM EITHER SIDE  
OF A LINE FROM 06N77W TO 09N85W TO 08N104W TO 0N116W TO 08N135W.  
   
..DISCUSSION
 
 
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  
 
SEE SPECIAL FEATURES PARAGRAPH ABOVE FOR INFORMATION ON THE  
GULF OF TEHUANTEPEC GALE WARNINGS.  
 
LIGHT AND VARIABLE WINDS AND 2 TO 4 FT SEAS EXPECTED W OF BAJA  
TODAY, THEN SEAS WILL BUILD FROM THE NW WITH 4 TO 7 FT SEAS AT  
13 TO 15 SECONDS FORECAST ACROSS THE WATERS W OF BAJA ON FRI  
NIGHT, THEN SUBSIDING SOME ON SAT INTO SUN. LONG-PERIOD NW SWELL  
IN THE FORM OF 7 TO 9 FT SEAS WILL REACH 30N120W ON SUN NIGHT,  
AND SPREAD S ACROSS THE WATERS W OF BAJA WITH 8 TO 13 FT SEAS AT  
17 TO 19 SECONDS FORECAST W OF BAJA MON NIGHT AND TUE.  
 
GULF OF CALIFORNIA: GENTLE TO MODERATE NW FLOW EXPECTED THROUGH  
TONIGHT. THE PRESSURE GRADIENT WILL THEN RELAX, WITH LIGHT AND  
VARIABLE WINDS ON FRI THROUGH MON. STRONG TO NEAR GALE NW FLOW  
EXPECTED TO DEVELOP N OF 25N ON MON NIGHT THROUGH TUE NIGHT,  
WITH SEAS BUILDING TO 12 FT ACROSS THE LONG FETCH WATERS.  
 
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND  
WITHIN 750 NM OF ECUADOR...  
 
GULF OF FONSECA...FRESH NW WINDS FORECAST TO BEGIN AROUND  
SUNRISE ON MON.  
 
GULF OF PAPAGAYO: FRESH TO LOCALLY STRONG NE NOCTURNAL DRAINAGE  
FLOW FORECAST TO BEGIN TONIGHT, WITH STRONG PULSES THROUGH TUE.  
SEAS OF 8 FT OR GREATER WILL PROPAGATE SW TO NEAT 08N92W ON  
TUE.  
 
LIGHT AND VARIABLE WINDS, AND 3 TO 5 FT SEAS, ARE EXPECTED  
ELSEWHERE THROUGH SUN NIGHT TO THE N OF THE MONSOON TROUGH WHICH  
HAS BEEN MEANDERING BETWEEN 09N AND 11N. MODERATE NE FLOW  
EXPECTED N OF THE GULF OF PAPAGAYO EARLY MON. MODERATE SOUTHERLY  
WINDS, AND 3 TO 6 FT SEAS, ARE FORECAST S OF THE MONSOON TROUGH.  
 
REMAINDER OF THE AREA...  
 
A COLD FRONT FROM 32N137W TO 29N140W WILL STALL TODAY WITH A  
SURFACE LOW DEVELOPING ALONG THE FRONT NEAR 30N140W TONIGHT. THE  
LOW WILL MOVE NE OF THE AREA ON FRI NIGHT. SCATTERED MODERATE  
ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 30 NM EITHER  
SODE OF A LINE FROM 20N135W TO 17N140W.  
 
COMBINED SEAS OF 8 TO 13 FT AT 14 TO 16 SECONDS IS CURRENTLY  
OBSERVED ACROSS THE DISCUSSION WATERS W OF A LINE FROM 32N128W  
TO 22N140W. THIS LONG PERIOD NW SWELL, IN THE FORM OF 8 TO 11 FT  
SEAS AT 13 TO 15 SECONDS, WILL PROPAGATE ACROSS THE WATERS W OF  
A LINE FROM 32N122W TO 12N137W EARLY FRI BEFORE BEGINNING TO  
SUBSIDE.  
 
ANOTHER COLD FRONT WILL MOVE E IN TO THE AREA REACHING FROM  
32N133W TO 23N140W ON SAT WITH 9 TO 12 FT SEAS AT 12 TO 17  
SECONDS IN THE WAKE OF THE FRONT.  
 

 
NELSON  
 
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