000
AXPZ20 KNHC 300317
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU DEC 30 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0200 UTC.

...ITCZ...
AXIS EXTENDS FROM LOW PRES 1006 MB AT 06N78W TO 04N84W TO 05N93W 
TO 06N104W TO 07N113W TO 06N140W. NO SIGNIFICANT CONVECTION 
NOTED NEAR AXIS.

...DISCUSSION...
W OF 100W...A STRONG SHORT WAVE TROUGH N OF 30N HAS MOVED INTO 
WRN N AMERICA TODAY AND HAD REACHED 118W EARLY THIS EVENING... 
EXTENDING SW TO NEAR 27N120W. AN ASSOCIATED COLD FRONT WAS JUST 
60-90 NM BEHIND THE UPPER TROUGH AND WAS NEARING THE W COAST OF 
BAJA CALIFORNIA ALONG 30N AT 0000 UTC. THE FRONT WILL CONTINUE 
SE  AND IS EXPECTED TO REACH FROM CENTRAL BAJA TO 24N130W BY THU 
MORNING. STRONG NW TO N WINDS BEHIND THE FRONT ARE GENERATING 
HIGH SEAS THAT ARE FORECAST TO BUILD TO 8 TO 13 FT OVERNIGHT. 
THE FRONT WILL CONTINUE SOUTH ON THU...REACHING FROM SOUTHERN 
BAJA TO 21N122W BY LATE THU...BEFORE DISSIPATING EARLY FRI. 
WINDS BEHIND THE FRONT WILL DIMINISH THU NIGHT AS THE SUPPORTING 
SHORT WAVE TROUGH LIFTS EASTWARD ACROSS THE ROCKIES. A BROAD 
1032 MB SURFACE HIGH PRES CENTERED NEAR 38N141W HAS ABSORBED 
INTO ITS ASSOCIATED RIDGE A WEAKER HIGH TO THE S...WITH THE NEW 
RIDGE EXTENDING S INTO THE SUBTROPICS BETWEEN 135W AND 155W.  
THIS RIDGE WILL SHIFT SE AND WEAKEN OVER THE NEXT FEW DAYS AND 
ALLOW STRONG TRADE WINDS FROM THE ITCZ TO 19N W OF 125W TO 
SLOWLY DIMINISH SLIGHTLY IN INTENSITY AND AREAL COVERAGE THROUGH 
THU. ASSOCIATED SEAS OF 8 TO 10 FT IN MIXED NE AND NW SWELL WILL 
GRADUALLY SUBSIDE TO LESS THAN 8 FT BY LATE FRI.  

E OF 100W...SW TO W FLOW ALOFT DOMINATES THE AREA. SIGNIFICANT 
GAP WINDS DURING THE PAST FEW DAYS HAVE DIMINISHED CONSIDERABLY 
DURING THE PAST 24-36 HOURS. IN THE GULF OF PAPAGAYO...FRESH TO 
STRONG NE TO E FLOW THROUGH THE SW CARIBBEAN WILL CONTINUE TO 
PUSH ACROSS SOUTHERN CENTRAL AMERICA AND THROUGH THE GULF OF 
PAPAGAYO. HOWEVER...THIS FLOW HAS ALREADY BEGUN TO TAPER OFF AS 
THE GRADIENT FLOW HAS DIMINISHED...LEAVING A NARROW PLUME OF NE 
TO E WINDS AT 20-25 KT. FURTHER SOUTH...A PERSISTENT 
QUASI-STATIONARY 1008 MB SURFACE LOW OFF THE COLOMBIAN COAST S 
OF PANAMA NEAR 06N78W WAS SUPPORTING A LARGE CLUSTER OF 
CONVECTION WITHIN 150 NM OF THE CENTER...AND FRESH SW FLOW S 
THROUGH SW OF THE CENTER. HOWEVER CONVECTION HAS DIED IN THE 
PAST FEW HOURS AS THE LOW HAS WEAKENED AND LLVL FORCING HAS 
DIMINISHED. 

GULF OF CALIFORNIA...AN AFTERNOON ASCAT PASS REVEALED THAT S TO 
SW WINDS IN THE N PART OF THE GULF HAD INCREASED 20 TO 25 KT IN 
ADVANCE OF COLD FRONT APPROACHING THE PENINSULA. WINDS WILL 
SHIFT W TO NW AT 20-25 KT BEHIND THE FRONT LATE TONIGHT THROUGH 
THU MORNING WHILE SOME SMALL ZONE OF SWLY FLOW NEAR 20 KT WILL 
CONTINUE S OF THE FRONT AS IT SHIFTS SE INTO CENTRAL PORTIONS 
THROUGH THU AFTERNOON. WINDS WILL DIMINISH ON BOTH SIDES OF 
FRONT THU NIGHT AS THE PRES GRADIENT WEAKENS. NWLY SWELL 
GENERATED BEHIND THIS FRONT WILL PROPAGATE SE AND REACH S OF 20N 
ACROSS THE EPAC FRI AFTERNOON.

$$
STRIPLING