000
AXPZ20 KNHC 050930
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED DEC 05 2012

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 07N78W TO 09N85W TO 07N91W WHERE 
IT TRANSITIONS TO THE ITCZ EXTENDING TO 08N115W TO 06N127W TO 
BEYOND 06N140W. SCATTERED MODERATE CONVECTION CAN BE FOUND ON 
EITHER SIDE OF THE ITCZ AXIS FROM 06N TO 10N BETWEEN 112W AND 
119W.

...DISCUSSION...

ALOFT...AN ANTICYCLONE IS CENTERED NEAR 26N118W WITH A RIDGE 
EXTENDING NNE TO A CREST OVER THE SW CONUS. A SHORTWAVE TROUGH 
IS MOVING ACROSS THE NW PORTION OF THE AREA BUT WILL DAMPEN OUT 
WITHIN THE NEXT 24 HRS. TO THE SW OF THE ANTICYCLONE...AN UPPER  
LEVEL TROUGH IS EVIDENT ROUGHLY ALONG 127W EXTENDING FROM A 
CUT-OFF LOW NEAR 20N127W TO 10N127W THEN CONTINUES SSE TO NEAR 
THE EQUATOR AT 122W. SATELLITE-DERIVED WINDS INDICATE THAT A 
SWLY DIFFLUENT PATTERN ALOFT IS PRESENT TO THE E OF THE 
TROUGH...AND IS HELPING TO SUSTAIN THE CONVECTIVE ACTIVITY 
PREVIOUSLY DESCRIBED ON EITHER SIDE OF THE ITCZ AXIS. AN AREA OF 
INCREASED MULTILAYERED CLOUDINESS WITH LIKELY EMBEDDED SHOWERS 
IS ALSO NOTED AHEAD OF THE TROUGH AXIS. THE CUT-OFF LOW AND THE 
ASSOCIATED TROUGH WILL REMAIN NEARLY STATIONARY OVER THE NEXT 24 
HOURS. A RIDGE PERSISTS OVER NORTHERN SOUTH AMERICA EXTENDING 
WWD ACROSS CENTRAL AMERICA AND THE EPAC WATERS TO NEAR 13N105W. 

AT THE SURFACE...HIGH PRES REMAINS IN CONTROL OF THE WEATHER 
PATTERN ACROSS MOST OF THE FORECAST REGION WITH A 1025 MB CENTER 
LOCATED NEAR 29N128W. THIS SYSTEM EXTENDS A RIDGE WWD TO PAST 
140W AND SE TO NEAR 18N110W. SCATTEROMETER DATA INDICATED 20 TO 
25 KT TRADE WINDS ON THE SOUTHERN PERIPHERY OF THE RIDGE... 
MAINLY FROM 07N TO 20N W OF 130W. SEAS CONTINUE TO SUBSIDE 
ACROSS THE REGIONAL WATERS...EXCEPT IN THE REGION OF THE TRADES 
WHERE SEA HEIGHTS WILL REMAIN IN THE 8-10 FT RANGE OVER THE NEXT 
48 HOURS. ADDITIONAL PULSES OF NW SWELL ARE RAISING SEAS TO 8 FT 
ACROSS THE FAR NW CORNER OF THE AREA...PARTICULARLY NW OF A LINE 
FROM 30N136W TO 28N140W BUT SEAS WILL SUBSIDE TO LESS THAN 8 FT 
IN THIS AREA LATER TODAY.  

LOOKING AHEAD...EXPECT INCREASING WINDS AND BUILDING SEAS OFF 
THE NORTHERN COAST OF BAJA CALIFORNIA BY THU AS A 1028 MB HIGH 
PRES SETTLES N OF THE FORECAST AREA. PRES GRADIENT WILL TIGHTEN 
BETWEEN THE HIGH AND LOWER PRES ALONG WESTERN MEXICO RESULTING 
IN NLY WINDS OF AROUND 20 KT OVER THE NE WATERS WITH SEAS OF 8-9 
FT BY FRI MORNING. 

GAP WINDS...
A COLD FRONT HAS MOVED INTO THE GULF OF MEXICO AND WILL DELIVER 
A ROUND OF COOLER AND DRIER AIR DOWN THE GULF COAST OF MEXICO... 
THROUGH THE CHIVELA PASS AND INTO THE GULF OF TEHUANTEPEC. BASED 
ON MARINE GUIDANCE...WINDS ARE EXPECTED TO REACH 30 KT THIS 
MORNING WITH SEAS BUILDING TO AROUND 11 FT LATER TONIGHT. ALL 
GLOBAL MODELS AND THE LATEST RUN OF THE NAM REGIONAL MODEL ARE 
IN AGREEMENT THAT WINDS WILL REMAIN BELOW GALE FORCE. IN 
ADDITION...THE EFS GALE PROBABILITY ALSO SUGGESTS NO GALE ACROSS 
THE GULF OF TEHUANTEPEC WITH THIS GAP WIND EVENT. WINDS ARE 
FORECAST TO DIMINISH TO LESS THAN 20 KT BY EARLY THU EVENING.

WINDS WILL CONTINUE TO PULSE IN THE GULF OF PAPAGAYO TO 20 KT 
DURING LATE NIGHT AND EARLY MORNING HOURS THEN DIMINISH BELOW 15 
KT IN THE AFTERNOON THROUGH FRI. 

$$
GR