286  
AXPZ20 KNHC 080927  
TWDEP  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
927 UTC WED NOV 8 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  
0915 UTC.  
   
..SPECIAL FEATURES
 
 
GULF OF TEHUANTEPEC: NOCTURNAL DRAINAGE FLOW WILL CONTINUE TO  
PULSE FROM STRONG TO NEAR GALE FORCE TODAY THROUGH TOMORROW.  
WINDS ARE FORECAST TO INCREASE TO MINIMAL GALE FORCE LATE THU  
AFTERNOON OR EARLY EVENING AS HIGH PRESSURE SURGES DOWN EASTERN  
MEXICO WITH AN ADVANCING COLD FRONT. GALES WILL THEN PULSE FOR  
THE FORESEEABLE FUTURE THROUGH THE UPCOMING WEEKEND AND INTO  
EARLY NEXT WEEK. WINDS WILL APPROACH STRONG GALE BY THE END OF  
THE WEEKEND AS THE PRESSURE GRADIENT TIGHTENS SLIGHTLY. SEAS WILL  
BUILD TO 10 TO 15 FT DURING THE GALE FORCE WINDS.  
   
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
 
 
 
THE MONSOON TROUGH AXIS EXTENDS FROM 10N83W TO 08N105W TO LOW  
PRESSURE NEAR 10N117W TO LOW PRESSURE NEAR 12N133W TO 08N140W.  
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 06N TO  
08N BETWEEN 80W AND 82W, FROM 07N TO 10N BETWEEN 93W AND 96W,  
FROM 07N TO 10N BETWEEN 98W AND 101W, AND ALSO WITHIN 180 NM  
EITHER SIDE OF THE AXIS BETWEEN 121W AND 129W.  
 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 04N TO  
07N WITHIN 90 NM OF THE COAST OF COLOMBIA, INCLUDING THE APPROACH  
TO THE PANAMA CANAL.  
   
..DISCUSSION
 
 
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  
 
A RIDGE WILL DOMINATE THE WATERS W OF BAJA CALIFORNIA THROUGH THE  
REST OF THE WEEK, WHILE A TROUGH WILL MEANDER BETWEEN THE COAST  
OF NW MEXICO AND THE GULF OF CALIFORNIA. MODERATE TO LOCALLY  
FRESH NW TO N FLOW WILL PREVAIL ACROSS THE WATERS W OF BAJA  
CALIFORNIA, INCREASING TO FRESH TO LOCALLY STRONG OFFSHORE OF  
THE NORTHERN WATERS THU NIGHT THROUGH FRI. A COLD FRONT IS  
EXPECTED TO WEAKEN BEFORE REACHING THE AREA ON FRIDAY, BUT THE  
ASSOCIATED LONG-PERIOD NW SWELL INDUCING SEAS IN THE RANGE OF 8  
TO 10 FT WILL PROPAGATE SOUTHEASTWARD ACROSS THE WATERS N OF 23N  
AND TO THE W OF BAJA CALIFORNIA ON FRIDAY, THEN SPREAD SOUTHWARD  
THROUGH ALL THE WATERS W OF BAJA ON SATURDAY WHILE SUBSIDING  
SLIGHTLY.  
 
GULF OF CALIFORNIA: MODERATE TO LOCALLY FRESH NW WINDS WILL  
CONTINUE THROUGH THE MORNING. THE PRESSURE GRADIENT WILL TIGHTEN  
A LITTLE RESULTING IN A NARROW SWATH OF FRESH TO LOCALLY STRONG  
NW WINDS FROM 25N TO 28N BY THE AFTERNOON. THE PRESSURE GRADIENT  
WILL RELAX WITH MODERATE NW FLOW ONLY TO THE S OF 26N BY  
THURSDAY EVENING. 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, BECOMING MODERATE OUT OF THE NW BY THE END OF  
THE 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 WINDS WILL  
PULSE DURING THE OVERNIGHT HOURS THROUGH EARLY THU, WITH SEAS  
BUILDING TO 5 OR 6 FT DOWNSTREAM NEAR 11N87W.  
 
LIGHT AND VARIABLE WINDS AND 4 TO 6 FT SEAS, ARE EXPECTED  
ELSEWHERE TO THE N OF 09N, WHILE MODERATE TO LOCALLY FRESH  
SOUTHERLY WINDS AND 5 TO 7 FT SEAS, ARE FORECAST S OF 09N THROUGH  
THE REMAINDER OF THE WEEK AND THE UPCOMING WEEKEND.  
 
REMAINDER OF THE AREA...  
 
A 1014 MB SURFACE LOW IS NEAR 30N125W. A DISSIPATING STATIONARY  
FRONT THAT OCCLUDES INTO THE LOW EXTENDS FROM 30N122W TO 23N129W.  
SCATTERED MODERATE CONVECTION IS WITHIN AN AREA BOUNDED BY  
30N123W TO 30N118W TO 26N123W TO 28N125W TO 30N123W. THE LOW IS  
FORECAST TO DISSIPATE DURING THE NEXT 24 HOURS. A 1010 MB  
SURFACE LOW IS ANALYZED IN THE MONSOON TROUGH NEAR 10N117W.  
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 180  
NM IN THE SW SEMICIRCLE OF THE LOW. A SURFACE TROUGH IS ANALYZED  
JUST N OF THE MONSOON TROUGH FROM 22N126W TO 13N131W. SCATTERED  
MODERATE AND ISOLATED STRONG CONVECTION IS FROM 13N TO 18N WITHIN  
180 NM E OF THE TROUGH AXIS.  
 
A COLD FRONT IS FORECAST TO REACH A POSITION FROM NEAR 32N138W  
TO 29.5N140W BY EARLY AFTERNOON, FOLLOWED BY A NEW SET OF LONG  
PERIOD NW SWELL. THE FRONT WILL REACH FROM NEAR 30N130W TO  
27N140W BY LATE TONIGHT, THEN WILL BEGIN TO DISSIPATE FROM  
30N130W TO 27N136W BY LATE THU NIGHT. THE REMNANTS WILL THEN  
DRIFT NW AS A TROUGH INTO THE EARLY PART OF THE WEEKEND. A NEW  
FRONT WILL BREACH JUST SE OF 30N140W BY SAT AFTERNOON, BUT WILL  
QUICKLY STALL BEFORE EVENTUALLY MERGING WITH THE OLD FRONTAL  
TROUGH INTO SUN. THE ASSOCIATED LONG PERIOD NW SWELL, WITH  
RESULTANT SEAS OF 8 TO 13 FT WILL PROPAGATE SOUTHEASTWARD THROUGH  
THE NORTHERN AND CENTRAL FORECAST WATERS WHILE GRADUALLY  
DECAYING AND SHRINKING IN COVERAGE THURSDAY NIGHT THROUGH FRIDAY  
NIGHT, AT WHICH TIME SEAS IN THE RANGE OF 8 TO 10 FT ARE EXPECTED  
TO BE CONFINED TO THE WATERS N OF 12N AND W OF 114W. THE SWELL  
WILL THEN SLOWLY SUBSIDE TO LESS THAN 8 FT THROUGHOUT THE WATERS  
BY EARLY NEXT WEEK.  
 

 
LEWITSKY  
 
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