000
AXPZ20 KNHC 132143
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
2205 UTC FRI DEC 13 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC...GALE FORCE NORTHERLY WINDS HAVE  
DIMINISHED TO 20-30 KT WITH SEAS BEGINNING TO SUBSIDE TO 8-14 
FT. CONDITIONS WILL CONTINUE TO IMPROVE WITH WINDS DIMINISHING 
TO 20 KT OR LESS AND SEAS SUBSIDING TO LESS THAN 8 FT BY 24 
HOURS. HOWEVER...THESE MORE TRANQUIL CONDITIONS WILL BE SHORT 
LIVED. ANOTHER STRONG COLD FRONT WILL MOVE THROUGH THE SW GULF 
OF MEXICO THIS WEEKEND...MOVING E OF THE NORTHERN EXTENT OF THE  
CHIVELA PASS LATE SAT INTO EARLY SUN. ANOTHER 30-35 KT NORTHERLY 
GALE FORCE WIND EVENT IS FORECAST TO COMMENCE IN THE GULF OF 
TEHUANTEPEC AT 42 HOURS...INCREASING TO AT LEAST 30-40 KT BY 48 
HOURS. SEAS WILL QUICKLY BUILD BACK UP TO 14 FT BY EARLY SUN 
AFTERNOON. ISOLATED BRIEF GUSTS TO STORM FORCE CANNOT BE RULED 
OUT EITHER AS INDICATED BY THE LATEST GRIDDED WIND GUST PACKAGE.
 
MEANWHILE...THE LONG DURATION OF THE NOW ENDED GALE FORCE WIND 
EVENT GENERATED A SIGNIFICANT PLUME OF NORTHEASTERLY SWELL WHICH 
HAS NOW PROPAGATED WELL SW-W AWAY FROM THE IMMEDIATE GULF OF 
TEHUANTEPEC REGION. THIS SWELL WILL CONTINUE TO PROPAGATE TO THE 
W THROUGH THE NEXT 48 HOURS...MIXING WITH SW AND NW SWELL WITH 
REINFORCING NW SWELL MOVING INTO THE NW WATERS N OF 13N W OF 
130W BY EARLY SUN AFTERNOON.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS FROM 06N77W TO 08N86W TO 06N100W    
TO 1010 MB LOW PRES NEAR 08N111W TO 10N125W TO 08N131W. THE ITCZ 
EXTENDS FROM 08N131W TO BEYOND 06N140W. SCATTERED MODERATE AND 
ISOLATED STRONG CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE 
AXIS E OF 84W...AND WITHIN 75 NM S OF THE AXIS BETWEEN 91W AND 
96W. SCATTERED MODERATE CONVECTION IS FROM 07N TO 10N BETWEEN 
110W AND 114W...FROM 10N TO 14N BETWEEN 116W AND 124W...WITHIN 
75 NM EITHER SIDE OF THE AXIS BETWEEN 124W AND 127W...AND ALSO 
FROM 07N TO 09N BETWEEN 133W AND 136W.

IN ADDITION...SCATTERED MODERATE TO STRONG CONVECTION IS FROM 
14N TO 20N BETWEEN 120W AND 127W...BETWEEN UPPER LEVEL RIDGING 
TO THE E AND UPPER LEVEL TROUGHING TO THE W.

...DISCUSSION... 

A FRONTAL TROUGH EXTENDS FROM 32N139W TO 26N146W. THE TROUGH 
WILL CONTINUE TO SHIFT WESTWARD TONIGHT. ASSOCIATED SEAS OF 8 FT 
OR GREATER MANAGED TO REMAIN JUST W AND N OF THE DISCUSSION 
WATERS. 

A RIDGE EXTENDS FROM 1030 MB HIGH PRES NEAR 33N130W...EXTENDING 
TO THE SE ALL THE WAY TO NEAR 15N107W. MEANWHILE SEMI-PERMANENT 
TROUGHING IS ALONG THE FAR NW COAST OF MAINLAND MEXICO. THIS 
PRESSURE PATTERN IS INDUCING FRESH NW-N WINDS IN THE SOUTHERN 
GULF OF CALIFORNIA. THE HIGH AND RIDGING WILL STRENGTHEN WHICH 
WILL INCREASE NORTHERLY WINDS TO FRESH TO STRONG LEVELS ACROSS 
THE ENTIRE GULF OF CALIFORNIA...AND SPILLING S TO 21N BY THIS 
TIME TOMORROW. WINDS ARE FORECAST TO PEAK AT 30 KT LATE SAT 
AFTERNOON/EARLY EVENING ALLOWING FOR SEAS TO BUILD TO UP TO 8-10 
FT. WINDS WILL THEN DIMINISH BACK TO FRESH TO STRONG LEVELS N OF 
24N BY EARLY SUN AFTERNOON AS THE PRESSURE GRADIENT THEN 
SLACKENS SLIGHTLY.

LOW PRES AT 1010 MB NEAR 08N111W IS MOVING W ALONG THE MONSOON 
TROUGH AROUND 10 KT. RECENT ASCAT SCATTEROMETER DATA INDICATED 
FRESH TO STRONG WINDS WITHIN 180 NM IN THE N QUADRANT WHERE SEAS 
OF 9-11 FT ARE ALSO LIKELY OCCURRING. THIS LOW IS FORECAST TO 
GRADUALLY WEAKEN AS IT REACHES TO 09N119W BY 48 HOURS WITH 
ASSOCIATED WINDS DIMINISHING BY THEN. MEANWHILE...THE PRESSURE 
GRADIENT BETWEEN THE ABOVE MENTIONED RIDGING AND THIS LOW WILL 
SUPPORT THE DEVELOPMENT OF FRESH TO STRONG TRADE WINDS ACROSS 
THE MAJORITY OF THE NORTHWESTERN FOURTH OF THE DISCUSSION WATERS 
BY 24 HOURS...DIMINISHING SLIGHTLY BY 48 HOURS AS THE LOW 
WEAKENS. SHORTER PERIOD NE WIND WAVES WILL MIX WITH THE NEW SET 
OF LONG PERIOD NW SWELL MENTIONED IN THE FIRST SECTION ABOVE.

GULF OF PAPAGAYO...FRESH TO STRONG NE WINDS AND 8-9 FT SEAS HAVE 
SHIFTED SW AWAY FROM THE IMMEDIATE GULF NOW EXTENDING FROM 08N 
TO 11N BETWEEN 87W AND 90W. A NEW ROUND OF FRESH TO STRONG GAP 
WINDS WILL SET UP IN THE IMMEDIATE GULF TONIGHT INTO EARLY 
SAT... DIMINISHING TO 20 KT OR LESS BY THIS TIME TOMORROW WITH 
ONLY MODERATE NE WINDS EXPECTED THEREAFTER THROUGH 48 HOURS.

$$
LEWITSKY