000
AXPZ20 KNHC 081523
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1605 UTC SUN DEC 08 2013

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.

...SPECIAL FEATURE... 

GULF OF TEHUANTEPEC...COOL DENSE AIR CONTINUES TO FUNNEL FROM 
THE SW GULF OF MEXICO THROUGH THE ISTHMUS OF TEHUANTEPEC THIS 
MORNING...SUPPORTING WINDS TO GALE FORCE OVER THE ADJACENT GULF 
OF TEHUANTEPEC. AN EARLIER SCATTEROMETER PASS INDICATED WINDS OF 
30 TO 40 KT IN THE GULF OF TEHUANTEPEC. THE STRONG FLOW WILL 
GRADUALLY DIMINISH THROUGH LATE TODAY AS THE AIRMASS N OF THE 
AREA MODIFIES AND SHIFTS EAST. WINDS ARE FORECAST TO DIMINISH 
BELOW GALE FORCE EARLY THIS AFTERNOON. SEAS WILL SUBSIDE BELOW 8 
FT BY LATE TODAY AS WELL. A RELATIVELY BENIGN CONDITIONS WILL 
REMAIN IN PLACE OVER THE GULF OF TEHUANTEPEC FROM LATE TONIGHT 
INTO TUE...WITH ONLY LIGHT TO MODERATE GAP BREEZES AT THEIR 
HIGHEST DURING MAINLY THE OVERNIGHT AND EARLY MORNING HOURS. 
LOOKING AHEAD...A SOMEWHAT STRONGER COLD FRONT WILL PUSH THROUGH 
THE WESTERN GULF OF MEXICO LATE TUE. THE COMBINATION OF THE 
DENSER AIR FUNNELING THROUGH THE GAP WITH STRONG HIGH PRES 
BUILDING BEHIND THE FRONT OVER NE MEXICO WILL DELIVER ANOTHER 
ROUND OF GALE FORCE WINDS TO THE GULF OF TEHUANTEPEC STARTING 
LATE TUE NIGHT OR EARLY WED MORNING AND CONTINUING THROUGH FRI. 
WINDS MAY REACH NEAR STORM FORCE BY LATE THU WITH SEAS BUILDING 
TO AROUND 15 FT. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 08N78W TO 09N87W TO 07N100W. THE 
ITCZ CONTINUES FROM 07N100W TO 08N120W TO BEYOND 06N140W. 
SCATTERED MODERATE CONVECTION IS NOTED FROM 05N TO 08N E OF 
81W...WITHIN 180 NM N OF TROUGH BETWEEN 95W AND 100W...AND FROM 
05N TO 08N BETWEEN 120W AND 127W.

...DISCUSSION... 

A 1027 MB HIGH PRESSURE IS CENTERED NEAR 29N131W WITH A RIDGE 
EXTENDING SE TO NEAR THE ISLANDS OF REVILLAGIGEDO. THE PRESSURE 
GRADIENT BETWEEN THE AREA OF HIGH PRESSURE AND LOWER PRESSURE IN 
THE VICINITY OF THE ITCZ IS SUPPORTING A LARGE AREA OF FRESH TO 
STRONG TRADES FROM 10N TO 20N W OF 127W WITH SEAS TO 11 FT. 
SCATTEROMETER DATA PROVIDED OBSERVATIONS OF THESE WIND SPEEDS.  
THE HIGH PRES WILL WEAKEN ON MON AS A WEAK COLD FRONT MOVES 
ACROSS THE N WATERS. NORTHERLY WINDS OF 20 KT AND BUILDING SEAS 
TO 9 FT IN NW SWELL WILL FOLLOW THE FRONT...FORECAST TO REACH A 
POSITION FROM 30N122W TO 28N130W TO 30N140W EARLY MON MORNING 
AND FROM 30N119W TO 22N130W TO 25N140W EARLY TUE MORNING AS A 
DISSIPATING FRONT. 

GULF OF CALIFORNIA...HIGH PRES WILL BUILD OVER THE GREAT BASIN 
OF THE WESTERN UNITED STATES. THIS WILL SET UP A STRONG GRADIENT 
FOLLOWED BY 20 TO 25 KT WINDS FUNNELING INTO THE NORTHERN GULF 
OF CALIFORNIA BY MONDAY AFTERNOON AND REACHING NEAR GALE FORCE 
BY MON EVENING. THE NW WINDS WILL PUSH DOWN THE LENGTH OF THE 
GULF THROUGH LATE MONDAY AND TUESDAY...WITH SEAS REACHING 8-9 FT.

GULF OF PAPAGAYO...WINDS WILL PULSE TO 25 KT...PRIMARILY DURING 
THE OVERNIGHT AND EARLY MORNING HOURS ON MONDAY. 

LONG PERIOD NW SWELL WILL PROPAGATE ACROSS THE N WATERS THROUGH 
TUE...RAISING SEAS TO AROUND 9 FT MAINLY N OF 20N AND W OF 130W 
THEN MERGING WITH LONG PERIOD CROSS EQUATORIAL SWELL...WAVE 
PERIOD BETWEEN 19 TO 20 SECONDS...BY TUE MORNING. 

$$
GR