000
AXPZ20 KNHC 312152
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JAN 31 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.

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

THE MONSOON TROUGH IS ALONG 03N78W TO 04N92W. THE INTERTROPICAL 
CONVERGENCE ZONE AXIS EXTENDS FROM 04N92W TO 07N120W TO 05N140W. 
SCATTERED MODERATE CONVECTION IS FROM 08N TO 18N BETWEEN 114W 
AND 124W.

...DISCUSSION...

1032 MB HIGH PRESSURE CENTERED N OF THE AREA NEAR 41N133W 
EXTENDS A RIDGE OVER THE FORECAST WATERS THROUGH 32N133W TO NEAR 
18N108W. THE PRESSURE GRADIENT BETWEEN THIS AREA OF HIGH 
PRESSURE AND LOWER PRESSURE IN THE VICINITY OF THE ITCZ IS 
MAINTAINING FRESH TO STRONG TRADES OVER THE AREA FROM 06N TO 14N 
BETWEEN 115W AND 127W AND ALSO WITHIN 300 NM N OF A LINE FROM 
07N130W TO 05N140W...AS INDICATED BY RECENT ASCAT AND OCEANSAT 
SCATTEROMETER PASSES. SEAS UP TO 12 FT ARE PRESENT IN THESE 
AREAS OF STRONGER WINDS...WHILE A SURROUNDING AREA OF 8-11 FT 
SEAS COVERS THE REMAINDER OF THE AREA W OF A LINE FROM 30N140W 
TO 10N110W TO 00N125W. THE HIGH PRESSURE AND ATTENDANT RIDGE IS 
FORECAST TO WEAKEN DURING THE NEXT 24-48 HOURS WHILE SHIFTING 
FURTHER N OF THE AREA. AS THIS OCCURS THE AREAL COVERAGE OF THE 
FRESH TO STRONG TRADES WILL BE LIMITED ALLOWING FOR THE 
SURROUNDING REMNANT SWELL TO DECAY.

THE PRESSURE GRADIENT BETWEEN THE RIDGE AND TROUGHING OVER 
WESTERN MEXICO IS RESULTING IN FRESH TO STRONG WINDS IN THE GULF 
OF CALIFORNIA FROM 24N TO 30N ALONG WITH SEAS TO 8 FT. WINDS ARE 
FORECAST TO BE 20 KT OR LESS IN ABOUT 18-24 HOURS AS THE HIGH 
PRES WEAKENS.

A COLD FRONT WILL ENTER THE NW PORTION LATE FRI NIGHT. THE FRONT 
WILL REACH FROM 30N138W TO 27N140W BY 06 UTC SAT...THEN FROM 
30N134W TO 18N140W BY SAT AFTERNOON. FRESH TO STRONG NORTHERLY 
WINDS WILL BE W OF THE FRONT ALONG WITH A NEW SET OF NW SWELL UP 
TO 15 FT. LOW PRESSURE MAY DEVELOP ALONG THE FRONT AS IT 
DEGENERATES INTO A REMNANT TROUGH BY LATE SAT THROUGH SUN. IF 
THIS LOW DOES INDEED DEVELOP AS SOME OF THE GLOBAL MODELS 
SUGGEST...IT COULD BRING A SIGNIFICANT INCREASE IN WINDS AND 
SEAS ACROSS THE NORTHERN WATERS. FUTURE MODEL GUIDANCE WILL 
CONTINUE TO BE MONITORED FOR UPDATED FORECAST INFORMATION.    

GAP WINDS...
GULF OF TEHUANTEPEC...A STRONG COLD FRONT HAS CLEARED THE ENTIRE 
GULF OF MEXICO THIS AFTERNOON AND THE DENSER AIR MASS BEHIND IT 
CONTINUES TO FUNNEL THROUGH THE CHIVELA PASS INTO THE GULF OF 
TEHUANTEPEC. THE SURGE IS ACCOMPANIED BY A TYPICAL SIGNATURE ARC 
CLOUD THAT IS EVIDENT IN VISIBLE SATELLITE IMAGERY THIS 
AFTERNOON. THIS CLOUD IS ALREADY REACHING AS FAR SOUTH AS 
09-10N. A GALE WARNING REMAINS IN EFFECT FOR THE GULF OF 
TEHUANTEPEC AND WAS CONFIRMED BY A RECENT 1804 UTC OCEANSAT PASS 
DEPICTING 30-40 KT WINDS. RECENT SHIP OBSERVATIONS IN THE 
VICINITY ALSO REPORTED 30-35 KT WINDS AND SEAS UP TO 14 FT 
DOWNWIND OF THE IMMEDIATE GULF OF TEHUANTEPEC. STRONG HIGH 
PRESSURE BUILDING BEHIND THE FRONT OVER EASTERN MEXICO AND THE 
WESTERN GULF OF MEXICO WILL HELP TO MAINTAIN GALE FORCE 
CONDITIONS IN THE GULF OF TEHUANTEPEC...DIMINISHING BELOW GALE 
FORCE BY EARLY SAT MORNING.

GULF OF PAPAGAYO...FRESH TO STRONG WINDS OVER THE GULF OF 
PAPAGAYO WILL FURTHER INCREASE TO 30 KT BY EARLY FRI MORNING. 
THIS WILL BUILD SEAS TO 11 FT JUST DOWNWIND OF THE GULF.

GULF OF PANAMA...FRESH TO STRONG WINDS WILL SPREAD ACROSS THE 
ISTHMUS OF PANAMA FROM THE SW CARIBBEAN SEA TO THE GULF OF 
PANAMA BY TONIGHT THROUGH FRI...DIMINISHING BY SAT AFTERNOON. 
THIS WILL RESULT IN SEAS BUILDING TO 8-9 FT DOWNWIND OF THE GULF.

$$
LEWITSKY