975  
AXPZ20 KNHC 211502  
TWDEP  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
1605 UTC SAT DEC 21 2024  
 
TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM  
03.4S TO 30N, EAST OF 120W INCLUDING THE GULF OF CALIFORNIA, AND  
FROM THE EQUATOR TO 30N, BETWEEN 120W AND 140W. THE FOLLOWING  
INFORMATION IS BASED ON SATELLITE IMAGERY, WEATHER OBSERVATIONS,  
RADAR, AND METEOROLOGICAL ANALYSIS.  
 
BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH  
1430 UTC.  
   
..SPECIAL FEATURES
 
 
GULF OF TEHUANTEPEC GALE WARNING: THE PRESSURE GRADIENT BETWEEN  
HIGH PRESSURE OVER THE WESTERN GULF OF MEXICO AND ADJACENT  
EASTERN MEXICO AND LOWER PRESSURE WITHIN THE EPAC MONSOON TROUGH  
WILL SUPPORT GALE-FORCE GAP WINDS IN THE GULF OF TEHUANTEPEC  
THROUGH SUN NIGHT. SEAS DURING THE WARNING EVENT WILL PEAK AT 12  
TO 14 FT. THE HIGH PRESSURE WILL SHIFT EAST BY EARLY MON, WITH  
THE PRESSURE GRADIENT LOOSENING. WINDS WILL DIMINISH WINDS BELOW  
GALE FORCE EARLY MON. PLEASE SEE THE LATEST NWS HIGH SEAS AND  
OFFSHORE WATERS FORECASTS ISSUED BY THE NATIONAL HURRICANE CENTER  
AT WEBSITE:  
HTTPS://WWW.NHC.NOAA.GOV/TEXT/MIAHSFEP2.SHTML AND  
HTTPS://WWW.NHC.NOAA.GOV/MARINE/OFFSHORES_EASTPAC.PHP FOR MORE  
DETAILS.  
 
SIGNIFICANT NW SWELL: A COMPLEX AND POWERFUL LOW PRESSURE NORTH  
OF THE AREA WILL GENERATE SEVERAL ROUNDS OF LARGE NW SWELL THAT  
WILL PROPAGATE INTO THE AREA THROUGH THE WEEKEND AND EARLY NEXT  
WEEK. THIS MORNING, SEAS GREATER THAN 12 FT COVER THE WATERS NW  
OF A LINE FROM 30N130W TO 18N140W, WITH SEAS PEAKING IN EXCESS OF  
20 FT OVER THE FAR NW WATERS. THE ROUGH TO VERY ROUGH SEAS WILL  
SPREAD SE, COVERING THE WATERS FROM WEST OF BAJA CALIFORNIA NEAR  
PUNTA EUGENIA TO 08N133W EARLY MON EVENING WHEN A REINFORCING SET  
OF NW SWELL ARRIVES WITH PEAK SEAS OF 21 FT NEAR 30N140W. NW  
SWELL WILL CONTINUE TO BE REINFORCED INTO THE MIDDLE OF NEXT  
WEEK. PLEASE SEE THE LATEST NWS HIGH SEAS FORECAST ISSUED BY THE  
NATIONAL HURRICANE CENTER AT WEBSITE:  
HTTPS://WWW.NHC.NOAA.GOV/TEXT/MIAHSFEP2.SHTML FOR MORE DETAILS.  
   
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
 
 
THE MONSOON TROUGH EXTENDS FROM 10N85W TO 07N104W. THE ITCZ  
EXTENDS FROM 07N104W TO 08N114W TO BEYOND 08N140W. SCATTERED  
MODERATE CONVECTION IS NOTED FROM 05N TO 09N E OF 80W, AND FROM  
04N TO 07N BETWEEN 92W AND 100W.  
   
..OFFSHORE WATERS WITHIN 250 NM OF MEXICO
 
 
PLEASE READ THE SPECIAL FEATURES SECTION FOR INFORMATION ON A  
GALE WARNING IN THE GULF OF TEHUANTEPEC, AND ON A SIGNIFICANT NW  
SWELL EVENT THAT WILL IMPACT THE WATERS OFFSHORE BAJA  
CALIFORNIA.  
 
ASIDE FROM THE GALE WARNING AREA, HIGH PRESSURE PREVAILS OVER THE  
WATERS WEST OF THE BAJA CALIFORNIA PENINSULA. THE PRESSURE  
GRADIENT BETWEEN THIS AREA OF HIGH PRESSURE AND A TROUGH OVER  
MEXICO IS SUPPORTING WITH GENTLE TO MODERATE WINDS ACROSS MUCH OF  
THE FORECAST WATERS. SEAS ARE IN THE 5 TO 7 FT OVER THE OPEN  
WATERS OFF MEXICO, AND 1 TO 3 FT OVER THE GULF OF CALIFORNIA.  
 
FOR THE FORECAST, OTHER THAN THE AFOREMENTIONED GALE WARNING IN  
THE TEHUANTEPEC REGION AND SIGNIFICANT NW SWELL, GENTLE TO  
MODERATE MAINLY N WINDS WILL INCREASE SLIGHTLY THIS WEEKEND AS A  
NE PACIFIC HIGH PRESSURE RIDGE BUILDS TOWARD THE REGION, AND  
WINDS WILL PULSE TO MODERATE TO FRESH AT TIMES OFFSHORE BAJA  
CALIFORNIA.  
 
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,  
AND WITHIN 750 NM OF ECUADOR...  
 
THE PRESSURE GRADIENT BETWEEN A SURFACE RIDGE OVER THE  
NORTHWESTERN CARIBBEAN SEA AND THE EPAC MONSOON TROUGH IS  
SUPPORTING FRESH TO STRONG NE GAP WINDS AND SEAS OF 5 TO 7 FT IN  
THE GULF OF PAPAGAYO REGION. LIGHT TO GENTLE WINDS PREVAIL  
ELSEWHERE N OF THE MONSOON TROUGH, EXCEPT WELL OFFSHORE GUATEMALA  
WHERE MODERATE TO FRESH WINDS ARE DOWNWIND FROM A GULF OF  
TEHUANTEPEC GAP WIND EVENT. SOUTH OF THE MONSOON TROUGH, GENTLE  
TO MODERATE SOUTHERLY WINDS AND 4 TO 6 FT SEAS IN MODERATE S TO  
SW SWELL PREVAIL, MIXED WITH NW SWELL FROM THE GULF OF  
TEHUANTEPEC GAP WIND EVENT.  
 
FOR THE FORECAST, THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE  
BUILDING TOWARD THE WESTERN CARIBBEAN AND THE EASTERN NORTH  
PACIFIC MONSOON TROUGH WILL SUPPORT PULSING FRESH TO STRONG NE  
GAP WINDS IN THE PAPAGAYO REGION INTO EARLY WED. GALES IN THE  
TEHUANTEPEC REGION WILL SUPPORT NORTHERLY SWELL AND ROUGH SEAS  
WELL OFFSHORE GUATEMALA THROUGH THE WEEKEND. ELSEWHERE, WINDS  
WILL BE MODERATE OR WEAKER WITH MODERATE SEAS THROUGH EARLY NEXT  
WEEK, PULSING TO MODERATE TO FRESH IN THE GULF OF PANAMA AT  
TIMES. SEAS MAY BUILD MID-WEEK IN NW SWELL.  
   
..REMAINDER OF THE AREA
 
 
PLEASE READ THE SPECIAL FEATURES SECTION ABOUT VERY ROUGH SEAS  
EXPECTED OVER NW WATERS THROUGH THE WEEKEND AND INTO EARLY NEXT  
WEEK.  
 
A FRONTAL BOUNDARY EXTENDS OVER THE FAR NW WATERS FROM 30N132W TO  
28N140W. HIGH PRESSURE OF 1022 MB IS CENTERED NEAR 25N125W. THE  
PRESSURE GRADIENT BETWEEN THESE FEATURES IS SUPPORTING MODERATE  
SW WINDS WITHIN 120 NM E OF THE COLD FRONT. LIGHT TO GENTLE WINDS  
ARE IN THE VICINITY OF THE HIGH CENTER. GENTLE TO MODERATE WINDS  
PREVAIL ELSEWHERE N OF 20N. THE PRESSURE GRADIENT BETWEEN THE  
AREA OF HIGH PRESSURE AND LOWER PRESSURE IN THE VICINITY OF THE  
ITCZ IS SUPPORTING MODERATE TO FRESH WINDS N OF THE ITCZ TO 19N  
AND W OF 118W. S OF THE ITCZ, GENTLE TO MODERATE TRADES PREVAIL.  
ASIDE FROM THE LARGE SWELL DISCUSSED ABOVE, SEAS ARE MAINLY IN  
THE 6-9 FT RANGE.  
 
FOR THE FORECAST, OTHER THAN THE NW SWELL AND VERY ROUGH SEAS  
MENTIONED IN THE SPECIAL FEATURES SECTIONS, LITTLE CHANGE IN  
WINDS ARE FORECAST OVER THE NEXT SEVERAL DAYS WHILE SEAS OF 8 FT  
OR GREATER WILL COVER MOST OF THE WATERS WEST OF 110W BY EARLY  
NEXT WEEK, AND THEN WEST OF 100W BY MID-WEEK.  
 

 
AL  
 
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