679  
AXPZ20 KNHC 090327 CCA  
TWDEP  
 
TROPICAL WEATHER DISCUSSION...CORRECTED  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
2205 UTC WED NOV 8 2017  
 
CORRECTED REMAINDER OF AREA SECTION  
 
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 TIGHT PRESSURE GRADIENT HAS SET UP OVER SOUTHEASTERN MEXICO,  
AND IS BRINGING STRONG NORTHERLY WINDS THROUGH THE ISTHMUS OF  
TEHUANTEPEC AND ACROSS THE GULF OF TEHUANTEPEC. THESE CONDITIONS  
ARE EXPECTED TO CONTINUE INTO THURSDAY MORNING. HIGH PRESSURE  
SURGING SOUTHWARD BEHIND A COLD FRONT MOVING ACROSS THE WESTERN  
GULF OF MEXICO WILL PUSH A COOLER AIR MASS TOWARDS THE EASTERN  
SLOPES OF THE SIERRA ORIENTAL MOUNTAINS ALONG EASTERN MEXICO.  
THIS WILL FURTHER INTENSIFY THE PRESSURE GRADIENT ALREADY IN  
PLACE ALLOWING FOR THESE WINDS TO INCREASE TO GALE FORCE BY EARLY  
THURSDAY AFTERNOON. A GALE WARNING IS ALREADY IN EFFECT FOR THE  
GULF OF TEHUANTEPEC THROUGH 48 HOURS. SEAS ARE EXPECTED TO BUILD  
TO THE RANGE OF 10-15 FT WITH THESE GALE CONDITIONS. MODEL  
GUIDANCE SUGGESTS THAT THIS EVENT WILL LAST THROUGH THE NEXT FEW  
DAYS.  
   
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
 
 
THE MONSOON TROUGH AXIS EXTENDS FROM 10N85W TO 09N100W TO  
08N110W TO LOW PRESSURE NEAR 10N121W 1009 MB TO 10N133W WHERE  
SCATTEROMETER WINDS FROM THIS AFTERNOON INDICATE THE ITCZ  
THEN BEGINS AND CONTINUES TO BEYOND 07N140W. SCATTERED MODERATE  
CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN 122W-126W,  
WITHIN 120 NM N OF THE AXIS BETWEEN 114W-117W AND ALSO WITHIN  
30 NM OF THE AXIS BETWEEN 103W-107W.  
   
..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-  
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.  
 
A RELATIVELY STRONG JET STREAM BRANCH FROM THE CENTRAL PACIFIC  
WATERS IS ADVECTING ABUNDANT MOISTURE ENE TOWARDS NORTHERN AND  
CENTRAL BAJA CALIFORNIA AND FAR SOUTHERN CALIFORNIA. THIS  
MOISTURE CONSISTS OF MULTILAYER CLOUDS WITH POSSIBLE ISOLATED  
SHOWERS AND THUNDERSTORMS UNDERNEATH THEM.  
 
GULF OF CALIFORNIA: THE PRESSURE GRADIENT WILL TIGHTEN A LITTLE  
RESULTING IN A NARROW SWATH OF FRESH TO LOCALLY STRONG NW WINDS  
FROM 25N TO 28N BY THIS 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.  
 
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND  
WITHIN 750 NM OF ECUADOR...  
 
GULF OF PAPAGAYO: MODERATE NE WINDS WILL PULSE DURING THE  
OVERNIGHT HOURS TONIGHT, WITH SEAS BUILDING TO 5 OR 6 FT  
DOWNSTREAM OF THE GULF 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...CORRECTED  
 
A 1021 MB HIGH PRESSURE SYSTEM IS ANALYZED NEAR 26N132W AND  
EXTENDS A RIDGE SOUTHEASTWARD TO NEAR 23N119W AND WESTWARD TO  
NEAR 26N139W. THIS HIGH CENTER IS FORECAST TO REMAIN NEARLY  
STATIONARY OVER THE NEXT 24 HOURS. A SURFACE TROUGH IS ANALYZED  
ACROSS THE WEST-CENTRAL WATERS AND JUST N OF THE MONSOON TROUGH.  
THE TROUGH EXTENDS FROM 19N132W TO 11N135W. SCATTERED MODERATE  
CONVECTION IS WITHIN 180 NM E AND WITHIN 60 NM W OF THE TROUGH  
FROM 13N TO 17N. RECENT ALTIMETER DATA INDICATED SEAS TO 8 FT  
BETWEEN THE TROUGH AXIS AND 140W. A 1009 MB LOW PRESSURE SYSTEM  
REMAINS EMBEDDED WITHIN THE MONSOON TROUGH NEAR 10N121W. AN  
ASCAT PASS FROM 1758Z THIS AFTERNOON HIGHLIGHTED WINDS OF 20 KT  
WITHIN 120 NM OF THE LOW IN THE NE QUADRANT, AND WITHIN 60 NM OF  
THE LOW IN THE SE QUADRANT. LATEST SATELLITE IMAGERY SHOWS  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM NW  
AND SE QUADRANTS OF THE LOW. THE LOW IS FORECAST TO MOVE NW TO  
NEAR 12N124W BY EARLY THURSDAY AFTERNOON AND TO NEAR 12N130W BY  
FRIDAY AFTERNOON.  
 
A COLD FRONT HAS MOVED INTO THE FAR NW CORNER OF THE FORECAST  
AREA. THE MAIN ISSUE WITH THIS FRONT WILL RELATED TO ITS  
IMPACTS ON WAVEHEIGHTS. IT IS FOLLOWED BY A NEW SET OF LONG  
PERIOD NW SWELL. THE FRONT WILL REACH FROM NEAR 32N130W TO  
28N134W, AND AS A WEAKENING STATIONARY FRONT TO 28N140W BY EARLY  
THURSDAY AFTERNOON, THEN BECOME NEARLY STATIONARY FROM 32N130W  
TO 27N140W ON THURSDAY EVENING AND BEGIN TO DISSIPATE ON FRIDAY.  
THE ASSOCIATED LONG PERIOD NW SWELL, WITH SEAS OF 8 TO 13 FT  
SEAS WILL PROPAGATE SOUTHEASTWARD THROUGH THE NORTHERN FORECAST  
WATERS WHILE DECAYING. 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 PRETTY STRONG JET STREAM BRANCH EXTENDS FROM THE DEEP TROPICS  
OF THE CENTRAL PACIFIC NORTHEASTWARD TOWARDS THE NE PORTION OF  
THE AREA. LATEST SATELLITE IMAGERY SHOWS BROKEN TO OVERCAST  
MULTILAYER CLOUDS ALONG AND S OF THE JETSTREAM BRANCH ROUGHLY  
WITHIN 90 NM EITHER SIDE OF A LINE FROM 19N134W TO 25N125W TO  
29N120W, AND WELL NE FROM THERE TOWARDS NORTHERN BAJA CALIFORNIA  
AND SOUTHERN CALIFORNIA AS MENTIONED ABOVE. UPPER DISTURBANCES  
RIDING NORTHEASTWARD ALONG THIS JET STREAM ARE HELPING TO  
ENHANCE THE AFOREMENTIONED CLOUDINESS AS WELL AS TRIGGER OFF  
SMALL PATCHES OF ISOLATED SHOWERS AND THUNDERSTORMS.  
THIS JETSTREAM BRANCH SET UP IS FORECAST TO CHANGE LITTLE OVER  
THE NEXT 24-48 HOURS.  
 

 
AGUIRRE  
 
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