964  
AXPZ20 KNHC 102205  
TWDEP  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH  
2145 UTC.  
   
..SPECIAL FEATURES
 
 
   
..A GALE WARNING IS IN EFFECT FOR THE GULF OF TEHUANTEPEC
 
 
A GALE WARNING IS IN EFFECT FOR THE GULF OF TEHUANTEPEC. THE 1800  
UTC SURFACE ANALYSIS DEPICT A TIGHT PRESSURE GRADIENT ACROSS  
SOUTHEASTERN MEXICO. THIS SUGGESTS THAT A GAP FLOW WIND EVENT IS  
OCCURRING AS A COOLER AIR MASS IN THE WAKE OF GULF OF MEXICO  
FRONTAL BOUNDARY SURGES SOUTHWARD ALONG THE EASTERN SLOPES OF THE  
SIERRA MADRE MOUNTAINS. IN THIS CASE, THE TIGHTNESS OF THE  
GRADIENT IS INDICATIVE THE SURGE OF THIS AIR MASS IS TRANSLATING  
AS STRONG TO GALE FORCE N-NE WINDS PUSHING SOUTHWARD OUT ACROSS  
THE GULF OF TEHUANTEPEC WHERE SEA SURFACE TEMPERATURES ARE QUITE  
WARM. LATEST MODEL GUIDANCE SUGGESTS THAT THE SYNOPTIC PATTERN  
SET UP WILL REMAIN QUITE FAVORABLE FOR GAP FLOW OF GALE FORCE  
NORTHERLY WINDS TO CONTINUE THROUGH THE NEXT FEW DAYS. THE  
GUIDANCE INDICATES THAT THE PRESENT N-NE 25-35 KT WINDS WILL  
INCREASE FURTHER TO 35-40 KT BEGINNING ON SUNDAY NIGHT AND  
THROUGH EARLY NEXT WEEK. SEAS ARE IN THE 10-14 FT RANGE WITH THE  
CURRENT GALE FORCE WINDS, BUT GIVEN THE EXPECTED LONG DURATION  
AND INTENSITY OF THESE WINDS THESE SEAS ARE FORECAST TO BUILD TO  
A MAXIMUM OF 17 OR 18 FT ON TUESDAY. THE LEADING EDGE OF 8 FT  
SEAS THAT WILL PROPAGATE SSW AWAY FROM THE GULF IS FORECAST TO  
REACH NEAR 08N100W ON TUESDAY.  
   
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
 
 
THE MONSOON TROUGH AXIS EXTENDS FROM SOUTHERN COSTA RICA TO  
08N93W TO 10N107W TO 08N116W TO LOW PRESSURE NEAR 10N129W 1010 MB  
TO 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS  
WITHIN 60 NM N OF THE AXIS BETWEEN 109W-118W. SCATTERED MODERATE  
CONVECTION IS WITHIN 60 NM S OF THE AXIS BETWEEN 83W-87W.  
   
..DISCUSSION
 
 
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  
 
PLEASE SEE THE SPECIAL FEATURES SECTION FOR INFORMATION ABOUT  
THE ONGOING GULF OF TEHUANTEPEC GALE WARNING.  
 
A RIDGE WILL DOMINATE THE WATERS W OF BAJA CALIFORNIA DURING THE  
NEXT SEVERAL DAYS, WHILE A TROUGH WILL MEANDER ALONG THE COAST  
OF NW MEXICO AND INTO THE GULF OF CALIFORNIA. MODERATE NW FLOW  
WILL PREVAIL ACROSS THE WATERS W OF BAJA CALIFORNIA FROM TODAY  
UNTIL EARLY MONDAY. THE SURFACE PRESSURE GRADIENT W OF BAJA  
CALIFORNIA WILL BEGIN TO SIGNIFICANTLY TIGHTEN ON SUNDAY NIGHT  
AND THROUGH EARLY NEXT WEEK AS HIGH PRESSURE TO THE W OF THE AREA  
BUILDS EASTWARD TOWARDS NORTHERN BAJA CALIFORNIA. AS A RESULT,  
EXPECT FRESH TO LOCALLY STRONG NW WINDS TO THE N OF ABOUT 25N  
AND E OF 119W TO THE COAST OF BAJA CALIFORNIA FROM EARLY MONDAY  
TO EARLY TUESDAY, WITH SEAS BUILDING TO AROUND 9 FT. LONG PERIOD  
NW SWELL PRODUCING SEAS TO THE RANGE OF 8-10 FEET WILL CONTINUE  
TO PROPAGATE SOUTHEASTWARD ACROSS THE WATERS N OF 23N TO THE W OF  
BAJA CALIFORNIA THROUGH TONIGHT WHILE SUBSIDING, AND REACH  
SOUTHWARD TO THE WATERS W OF THE SOUTHERN PORTION OF THE  
PENINSULA ON SUNDAY AS IT SUBSIDES FURTHER TO 7-8 FT.  
 
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND  
WITHIN 750 NM OF ECUADOR...  
 
LIGHT VARIABLE WINDS, AND SEAS OF 4-6 FT, ARE EXPECTED N OF  
09N, WHILE MODERATE TO LOCALLY FRESH SOUTHERLY WINDS AND SEAS OF  
5-7 FT ARE FORECAST S OF 09N THROUGH EARLY NEXT WEEK.  
 
REMAINDER OF THE AREA...  
 
LONG PERIOD NW SWELL THAT FOLLOWED IN BEHIND A FORMER FRONTAL  
SYSTEM THAT RECENTLY DISSIPATED OVER THE NORTHERN WATERS IS  
CONFINED TO NW AND N OF A LINE FROM 30N116W TO 20N121W TO  
12N127W TO 14N140W, WITH INDUCED SEAS OF 8-10 FT. THIS SWELL  
IS BEGINNING TO MIX WITH A SOUTHERLY SWELL COMPONENT. THE NW  
SWELL WILL PROPAGATE SOUTHEASTWARD AND SOUTHWARD THROUGH SATURDAY  
NIGHT REACHING TO AN AREA DEFINED FROM 08N-20N BETWEEN 114W-131W  
AND FROM 12N-20N W OF 131W BY SUNDAY AFTERNOON AND FROM NEAR  
12N-20N W OF 124W BY MONDAY AFTERNOON.  
 
GLOBAL MODEL GUIDANCE AS WELL THE MEDIUM RANGE GUIDANCE  
COORDINATED BETWEEN WPC AND NHC POINTS TO A LATE SEASON  
TROPICAL LOW PRESSURE SYSTEM EXPECTED TO DEVELOP ALONG THE  
MONSOON TROUGH NEAR 12N133W BY EARLY SUNDAY AFTERNOON OR POSSIBLY  
SOONER. THE GUIDANCE INDICATES THE PRESSURE GRADIENT BETWEEN  
THE LOW AND HIGH PRESSURE RIDGING THAT EXISTS OVER THE AREA WILL  
PINCH OFF INTO A SWATH OF NE-E WINDS WITHIN ABOUT 120 NM OF THE  
LOW IN ITS NORTHERN SEMICIRCLE ON SUNDAY WITH ASSOCIATED SEAS  
OF 9-11 FT. THE LOW IS NOT EXPECTED TO DEVELOP INTO A TROPICAL  
CYCLONE THROUGH SUNDAY AS THE UPPER LEVEL WINDS WILL REMAIN  
UNFAVORABLE. FOR NOW, THE LOW ONCE IT FORMS, IS EXPECTED TO  
TRACK IN A GENERAL WEST TO NORTHWESTWARD DIRECTION THROUGH  
MONDAY.  
 
A WEAK SURFACE TROUGH IS ANALYZED NEAR 137W FROM 11N-18N MOVING  
WESTWARD ABOUT 15 KT. THE TROUGH LIES UNDERNEATH THE EASTERN  
PERIPHERY OF A LARGE UPPER LEVEL TROUGH THAT IS JUST W OF THE  
AREA NEAR 141W. UPPER LEVEL DIVERGENCE E OF THE UPPER TROUGH IS  
HELPING TO SUSTAIN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS  
WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH. UPPER LEVEL  
DEBRIS CLOUDINESS FROM THIS ACTIVITY IS BEING ADVECTED  
NORTHEASTWARD TOWARDS NORTHERN BAJA CALIFORNIA AND SOUTHERN  
CALIFORNIA ALONG A STRONG JETSTREAM BRANCH THAT RIDES ALONG THE  
EASTERN PORTION OF THE UPPER TROUGH. THE SURFACE TROUGH WILL  
MOVE W OF THE AREA ON SATURDAY AS THE UPPER TROUGH SLOWLY MOVES  
EASTWARD.  
 

 
AGUIRRE  
 
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