000
AXPZ20 KNHC 151518
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED DEC 15 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1345 UTC.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE AXIS IS FROM 08N83W TO 04N92W TO 
07N104W TO 06N111W TO LOW PRES 09N125W TO 08N140W. SCATTERED 
MODERATE CONVECTION LIES WITHIN 210 NM N OF AXIS BETWEEN 133W 
AND 138W. SCATTERED MODERATE CONVECTION ALSO LIES WITHIN 240 NM 
S AND 120 NM N SEMICIRCLE OF THE LOW PRES SYSTEM EMBEDDED IN THE 
ITCZ.

...DISCUSSION...

A WEAK RIDGE STEMMING FROM 1021 MB HIGH PRES NEAR 26N140W 
DOMINATES THE WATERS N OF 15N AND W OF 115W. A SMALL AREA OF 
FRESH TRADE WINDS WILL PERSIST THROUGH TONIGHT ON THE S 
PERIPHERY OF THE RIDGE OVER FAR W WATERS FROM 09N TO 20N. THE 
RIDGE WILL WEAKEN TODAY AS A LOW PRES SYSTEM NEARS THE NW CORNER 
OF THE AREA. THIS SYSTEM WILL DRAG A COLD FRONT INTO WATERS N OF 
27N THU AND WEAKEN FRI. A SECOND AND STRONGER LOW PRES SYSTEM 
WILL FOLLOW...APPROACHING THE NW CORNER OF THE AREA LATE THU 
INTO FRI. EXPECT SW WINDS OF 20 KT AND SEAS OF 8 FT OR LESS OVER 
NW WATERS AHEAD OF THIS SYSTEM FRI MORNING.

A WEAK AREA OF LOW PRES IS ANALYZED ALONG THE ITCZ NEAR 09N125W. 
A TROUGH EXTENDS FROM 10N123W TO THE LOW CENTER AND THEN TO 
08N127W. A CLUSTER OF MODERATE CONVECTION NEAR THE LOW CENTER IS 
DESCRIBED IN THE ITCZ SECTION. THE 0604 UTC ASCAT PASS SHOWED 20 
KT NE WINDS N OF THE TROUGH AND 20 KT SOUTHERLY WINDS FEEDING 
INTO THE LOW FROM THE SOUTH WITH BUOY 51015 NEAR 05N125W 
REPORTING WINDS AS HIGH AS 18 KT AT 0800 UTC. THIS LOW IS 
FORECAST TO CONTINUE TO MOVE WWD OVER THE NEXT COUPLE OF DAYS. 

ELSEWHERE...WINDS AND SEAS ACROSS MOST OF THE EASTERN NORTH 
PACIFIC FORECAST WATERS WILL CONTINUE TO BE RELATIVELY TRANQUIL 
THE NEXT FEW DAYS WITH THE EXCEPTION OF THE LOCATIONS IMPACTED 
BY GAP WINDS. SHORT PERIOD SWELLS OUT OF THE NE GENERATED FROM 
THE GAP AREAS OF TEHUANTEPEC AND PAPAGAYO HAVE MERGED TO THE SW 
OF THE GAPS AND ARE PRIMARILY AFFECTING THE WATERS FROM 05N TO 
14N BETWEEN 90W AND 107W WITH SEAS AS HIGH AS 9 FT. LOOK FOR THE 
SWELLS TO SUBSIDE BELOW 8 FT BY THU MORNING AFTER THE WINDS IN 
TEHUANTEPEC AND PAPAGAYO DIMINISH.

GAP WINDS...
A HIGH RESOLUTION ASCAT PASS FROM 0244 UTC PROVIDED OBSERVATIONS 
OF 20 TO 25 KT WINDS THROUGH THE GULFS OF PAPAGAYO AND FONSECA 
WHILE THE MOST RECENT WINDSAT PASS AT 0118 UTC VERIFIED THE 
EXISTENCE OF N WINDS OF 20 TO 25 KT DOWNSTREAM OF THE GULF OF 
TEHUANTEPEC. THERE HAVE BEEN NO NEW OBSERVATIONS OFFSHORE SINCE 
THESE PASSES. WINDS IN THE GULFS OF TEHAUNTEPEC AND FONSECA ARE 
EXPECTED TO DIMINISH THIS AFTERNOON WHILE WINDS IN THE GULF OF 
PAPAGAYO ARE EXPECTED TO REMAIN STRONG TODAY AND ARE MORE LIKELY 
TO PULSE TO 20 KT CLOSE TO THE COAST INTO FRI MORNING.

THERE HAS ALSO BEEN AN ABSENCE OF NEW OBSERVATIONS IN THE GULF 
OF PANAMA FOR SEVERAL HOURS. NORTHERLY WINDS IN THE 20 TO 25 KT 
RANGE S OF THE GULF TO 04N ARE BELIEVED TO BE CONTINUING BASED 
ON THE COMPUTER MODEL GUIDANCE. WINDS ARE EXPECTED TO GRADUALLY 
DIMINISH TO AROUND 20 KT THROUGH THU MORNING AND THEN SHRINK 
NORTHWARD CLOSER TO THE COAST THROUGH FRI MORNING.

$$
SCHAUER/GR