487  
AXPZ20 KNHC 070925  
TWDEP  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
925 UTC TUE NOV 7 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  
0900 UTC.  
   
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
 
 
 
THE MONSOON TROUGH AXIS EXTENDS FROM 10N84W TO 08N98W TO LOW  
PRESSURE NEAR 09N113W TO LOW PRESSURE NEAR 11N133W TO 10N140W.  
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 08N TO  
10N BETWEEN 86W AND 88W, AND ALSO FROM 08N TO 10N BETWEEN 99W AND  
102W. SCATTERED MODERATE CONVECTION IS FROM 08N TO 11N BETWEEN  
134W AND 138W.  
   
..DISCUSSION
 
 
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  
 
A NW TO SE ORIENTED RIDGE WILL LINGER ACROSS THE WATERS W OF BAJA  
CALIFORNIA THROUGH THE WEEK AND UPCOMING WEEKEND, WITH INVERTED  
TROUGHING FROM NW TO SE ACROSS THE GULF OF CALIFORNIA. MODERATE  
TO FRESH NW TO N FLOW WILL PREVAIL ACROSS THE WATERS W OF BAJA  
CALIFORNIA, INCREASING TO FRESH TO STRONG OFFSHORE OF THE  
NORTHERN WATERS THU NIGHT THROUGH FRI. A COLD FRONT IS EXPECTED  
TO WEAKEN BEFORE REACHING THE AREA ON FRI, BUT THE ASSOCIATED  
LONG-PERIOD NW SWELL IN THE FORM OF 6 TO 9 FT SEAS WILL ARRIVE  
ACROSS THE WATERS N OF 23N W OF BAJA EARLY FRI, WITH SEAS OF 7 TO  
10 FT EVERYWHERE W OF BAJA ON SAT.  
 
GULF OF TEHUANTEPEC: PULSES OF STRONG NORTHERLY DRAINAGE FLOW,  
WITH SEAS BUILDING TO A MAX OF 8 TO 9 FT, ARE FORECAST THROUGH  
EARLY THU. THESE NORTHERLY GAPS WINDS ARE THEN EXPECTED TO  
INCREASE TO NEAR GALE FORCE ON THU MORNING, FURTHER INCREASE TO  
MINIMAL GALE FORCE ON THU EVENING, AND CONTINUE AT GALE FORCE  
THROUGH SUNRISE ON FRI, WITH SEAS THEN BUILDING TO 14 TO 17 FT  
DOWNSTREAM OF THE GULF NEAR 14.5N95.5W ON THU NIGHT. GALE FORCE  
WINDS ARE THEN EXPECTED AGAIN LATE FRI NIGHT INTO EARLY SAT.  
 
GULF OF CALIFORNIA: MODERATE TO LOCALLY FRESH NW FLOW WILL  
PERSIST THROUGH THIS EVENING. THE PRESSURE GRADIENT WILL THEN  
TIGHTEN A LITTLE RESULTING IN A NARROW SWATH OF STRONG NW WINDS  
FROM 25N TO 27N ON WED. THE PRESSURE GRADIENT WILL RELAX WITH  
MODERATE NW FLOW ONLY TO THE S OF 26N BY LATE THU. MAINLY LIGHT  
AND VARIABLE WINDS AND SEAS OF 2 FT OR LESS WILL THEN PREVAIL FOR  
THE END OF THE WEEK INTO THE UPCOMING WEEKEND.  
 
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND  
WITHIN 750 NM OF ECUADOR...  
 
GULF OF PAPAGAYO: MODERATE TO LOCALLY FRESH N TO NE DRAINAGE  
WINDS ARE FORECAST DURING THE OVERNIGHT HOURS THROUGH FRI NIGHT,  
WITH SEAS BUILDING TO 7 FT DOWNSTREAM NEAR 11N87W.  
 
LIGHT AND VARIABLE WINDS AND 3 TO 6 FT SEAS, ARE EXPECTED  
ELSEWHERE TO THE N OF 09N, WHILE MODERATE TO LOCALLY FRESH  
SOUTHERLY WINDS AND 4 TO 7 FT SEAS, ARE FORECAST S OF 09N  
THROUGH THE REMAINDER OF THE WEEK AND INTO THE UPCOMING WEEKEND.  
 
REMAINDER OF THE AREA...  
 
A 1014 MB SURFACE LOW IS QUASI-STATIONARY NEAR 30.5N127W WITH A  
TROUGH EXTENDING FROM THE LOW TO 24N135W. SCATTERED MODERATE  
CONVECTION IS BETWEEN 75 NM AND 150 NM SE OF THE TROUGH. RECENT  
SCATTEROMETER PASSES SHOWED FRESH TO STRONG NE TO E WINDS ON THE  
NW SIDE OF THE LOW TO THE N OF 30N, WITH MODERATE TO FRESH WINDS  
S OF 30N AND W OF THE TROUGH. RESIDUAL NE SWELLS OF 8 TO 9 FT  
WILL SUBSIDE TO LESS THAN 8 FT BY THE AFTERNOON.  
 
A 1012 MB SURFACE LOW IS EMBEDDED IN THE MONSOON TROUGH NEAR  
09N113W. VERY ACTIVE SCATTERED MODERATE TO STRONG CONVECTION IS  
WITHIN 360 NM IN THE SW SEMICIRCLE OF THE LOW, WITH A MID TO  
UPPER LEVEL TROUGH ALSO PRESENT IN THE VICINITY. THE LOW IS  
FORECAST TO MOVE WESTWARD DURING THE NEXT FEW DAYS.  
 
A COLD FRONT WILL MOVE INTO THE NW PORTION WED AFTERNOON BRINGING  
A NEW SET OF NW SWELL WITH IT. THE FRONT WILL EXTEND FROM 30N137W  
TO 29N140W BY WED EVENING, THEN WILL STALL FROM 30N130W TO  
26N140W BY EARLY FRI AS HIGH PRESSURE AHEAD OF IT HOLDS FIRM. THE  
FRONT WILL THEN DRIFT BACK NW AS A TROUGH INTO THE UPCOMING  
WEEKEND. THE ASSOCIATED LONG-PERIOD NW SWELL IN THE FORM OF 8 TO  
13 FT SEAS WILL PROPAGATE SE WHILE DECAYING. SEAS OF 8 FT OR  
GREATER WILL COVER THE WATERS N OF 15N W OF 115W LATE IN THE  
WEEK, THEN WILL BEGIN TO SUBSIDE TO LESS THAN 8 FT DURING THE  
UPCOMING WEEKEND.  
 

 
LEWITSKY  
 
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