153  
AXPZ20 KNHC 100319  
TWDEP  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
0405 UTC FRI NOV 10 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH  
0300 UTC.  
   
..SPECIAL FEATURES
 
 
A GALE WARNING IS IN EFFECT FOR THE GULF OF TEHUANTEPEC. HIGH  
PRESSURE SURGING SOUTHWARD BEHIND A COLD FRONT MOVING ACROSS THE  
WESTERN GULF OF MEXICO IS PUSHING A COOLER AIR MASS SOUTHWARD  
TOWARDS THE EASTERN SLOPES OF THE SIERRA ORIENTAL MOUNTAINS  
ALONG EASTERN MEXICO. THIS HAS SIGNIFICANTLY TIGHTEN THE  
PRESSURE GRADIENT ALREADY IN PLACE ACROSS SOUTHEASTERN MEXICO  
ALLOWING FOR GALE FORCE NORTHERLY WINDS TO PUSH THROUGH THE  
ISTHMUS OF TEHUANTEPEC AND OUT ACROSS THE GULF WHERE WARM SEA  
SURFACE TEMPERATURES ARE PRESENT. THESE GALE FORCE ARE EXPECTED  
TO INCREASE TO THE RANGE OF 30-40 KT TONIGHT ALONG WITH SEAS  
BUILDING TO THE RANGE OF 10-15 FT. THE GALE FORCE WINDS WILL ONLY  
DIMINISH SLIGHTLY ON FRIDAY AND THROUGH SATURDAY, HOWEVER THE  
RESULTANT SEAS WILL REMAIN WITHIN THE SAME RANGE. MODEL GUIDANCE  
SUGGESTS THAT THIS EVENT WILL LAST THROUGH EARLY NEXT WEEK, WITH  
WINDS INCREASING AGAIN TO 35-40 KT SUNDAY NIGHT THROUGH MONDAY  
NIGHT. DURING THIS TIME PERIOD, SEAS ARE FORECAST TO BUILD TO  
14-16 FT.  
   
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
 
 
THE MONSOON TROUGH AXIS EXTENDS FROM 10N84W TO 09N92W TO  
09N101W TO 09N111W TO 08N118W TO LOW PRESSURE NEAR 10N125W 1009  
MB AND TO BEYOND 09N140W. SCATTERED MODERATE ISOLATED STRONG  
CONVECTION IS SEEN WITHIN 120 NM S OF THE AXIS BETWEEN 108W-111W,  
AND WITHIN 60 NM OF THE AXIS BETWEEN 121W-125W. SCATTERED  
MODERATE CONVECTION IS NOTED FROM 06N-08N BETWEEN 80W-83W, AND  
ALSO WITHIN 60 NM OF THE AXIS BETWEEN 105W-108W.  
   
..DISCUSSION
 
 
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  
 
PLEASE SEE THE SPECIAL FEATURES SECTION FOR INFORMATION ON THE  
ONGOING GULF OF TEHUANTEPEC GALE WARNING.  
 
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 THIS EVENING THROUGH FRIDAY AS THE PRESSURE  
GRADIENT SLIGHTLY TIGHTENS BETWEEN A HIGH PRESSURE CENTER OVER  
THE NORTHERN FORECAST WATERS AND THE AFOREMENTIONED TROUGH. 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 8-10 FT WILL PROPAGATE SOUTHEASTWARD ACROSS THE  
WATERS N OF 23N AND TO THE W OF BAJA CALIFORNIA ON FRIDAY, THEN  
SPREAD SOUTHWARD THROUGH ALL OF THE WATERS W OF BAJA ON SATURDAY  
WHILE SLOWLY SUBSIDING.  
 
LOOKING BEYOND THE 48 HOUR FORECAST PERIOD OF THE DISCUSSION,  
THE PRESSURE GRADIENT W OF BAJA CALIFORNIA WILL SIGNIFICANTLY  
TIGHTEN EARLY NEXT WEEK ALLOWING FOR STRONG NW WINDS TO DEVELOP  
OVER THOSE WATERS ALONG WITH SEAS POSSIBLY BUILDING TO AROUND 9  
FT N OF ABOUT 25N.  
 
GULF OF CALIFORNIA: A RELATIVELY TIGHT PRESSURE GRADIENT IS  
SUPPORTING MODERATE TO FRESH NW FLOW ACROSS THE CENTRAL AND  
SOUTHERN GULF, WITH GENTLE TO MODERATE NW FLOW TO THE N. SEAS ARE  
2 FT OR LESS IN THE NORTHERN GULF, AND 3-4 FT ELSEWHERE. THE  
GRADIENT WILL SLACKEN ON FRIDAY ALLOWING FOR WINDS TO BECOME  
GENERALLY LIGHT AND VARIABLE AND REMAIN AS SUCH THROUGH SATURDAY,  
WITH SEAS SUBSIDING TO 2 FT OR LESS, EXCEPT FOR HIGHER SEAS OF  
3-5 FT NEAR THE ENTRANCE OF THE GULF.  
 
ELSEWHERE, MAINLY GENTLE TO MODERATE NW FLOW AND 4 TO 6 FT SEAS  
WILL PREVAIL THROUGH SATURDAY.  
 
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND  
WITHIN 750 NM OF ECUADOR...  
 
GULF OF PAPAGAYO: NOCTURNAL DRAINAGE FLOW WILL SUPPORT PULSING  
MODERATE TO FRESH WINDS DURING THE OVERNIGHT HOURS FOR THE NEXT  
SEVERAL DAYS, WITH SEAS OCCASIONALLY BUILDING TO 5 OR 6 FT  
DOWNSTREAM OF THE GULF NEAR 11N87W.  
 
LIGHT AND VARIABLE WINDS AND SEAS OF 4-6 FT ARE EXPECTED  
ELSEWHERE TO THE N OF 09N, WHILE MODERATE TO LOCALLY FRESH  
SOUTHERLY WINDS AND SEAS OF 5-7 FT ARE FORECAST S OF 09N THROUGH  
THE NEXT SEVERAL DAYS.  
 
REMAINDER OF THE AREA...  
 
THE COLD FRONT THAT MOVED ACROSS THE NW WATERS DURING THE PAST  
COUPLE OF DAYS IS ANALYZED AS A DISSIPATING STATIONARY FRONT  
FROM NEAR 32N126W TO 28N135W TO 27N140W. A NEW SET OF LONG  
PERIOD NW SWELL FOLLOWS THE FRONT, WITH SEAS IN THE RANGE OF 8-11  
FT IN NW SWELL, EXCEPT FOR HIGHER SEAS IN THE RANGE OF 10-13 FT  
N OF 29N. THIS SWELL EVENT WILL PROPAGATE SOUTHEASTWARD THROUGH  
THE AREA REACHING THE WATERS W OF BAJA CALIFORNIA AS PREVIOUSLY  
MENTIONED. THE FRONT WILL DISSIPATE BY FRIDAY EVENING. SEAS OF 8  
FT OR GREATER WILL COVER THE WATERS N OF 15N W OF 115W BY FRIDAY  
EVENING, THEN BEGIN TO SUBSIDE TO NEAR 8 FT THROUGHOUT THE  
WATERS BY SUNDAY EVENING. A SURFACE TROUGH IS ALONG 138W FROM  
12N-17N. LATEST SATELLITE IMAGERY SHOWS DECREASING SCATTERED  
MODERATE CONVECTION WITHIN 120 NM E OF THE TROUGH FROM 19N-22N.  
A TIGHT PRESSURE GRADIENT OVER THE NORTHERN PART OF TROUGH IS  
PRODUCING NE-E WINDS OF 20 KT FROM 19N-22.5N AND BETWEEN 136W-  
140W.  
 
A WEAK LOW PRESSURE OF 1008 MB AS DESCRIBED ABOVE REMAINS ALONG  
THE MONSOON TROUGH NEAR 10N125W, AND WILL CONTINUE TO MOVE  
WESTWARD THROUGH THE UPCOMING WEEKEND AND INTO EARLY NEXT WEEK.  
MODEL GUIDANCE INDICATES A TIGHTENING PRESSURE GRADIENT BETWEEN  
THE LOW AND AND BUILDING HIGH PRESSURE TO THE N DURING THE  
WEEKEND INTO EARLY NEXT WEEK. THIS MAY ALLOW FOR TRADES TO  
INCREASE TO FRESH TO STRONG ACROSS THE WATERS S OF 20N AND N OF  
THE MONSOON TROUGH/ITCZ, SUPPORTING FRESH SEAS OF 8-10 FT.  
 

 
AGUIRRE  
 
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