000
AXPZ20 KNHC 282206
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI DEC 28 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 1500 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 07N78W TO 08N85W TO 07N90W. ITCZ 
CONTINUES FROM 07N90W TO 06N110W TO 09N120W TO 07N140W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE 
OF MONSOON TROUGH AXIS E OF 85W...FROM 09N TO 14N BETWEEN 110W 
AND 115W...AND WITHIN 90 NM N OF AXIS W OF 135W.THE 

...DISCUSSION...

E OF 110W...
A STRONG GALE IS EXPECTED TO DEVELOP THROUGH THE GULF OF 
TEHUANTEPEC OVER THE NEXT 24 HOURS. A COLD FRONT IN THE NW GULF 
OF MEXICO WILL REACH THE NW BAY OF CAMPECHE SAT MORNING WITH THE 
NORTHERLY WINDS SURGING THROUGH THE CHIVELA PASS INTO THE GULF 
OF TEHUANTEPEC BY SAT AFTERNOON. THESE N WINDS WILL RAPIDLY 
BUILD TO GALE FORCE SAT EVENING...WITH NEAR STORM CONDITIONS 
EXPECTED OVERNIGHT SATURDAY. 

FARTHER SOUTH...WINDS WILL PULSE ACROSS THE GULF OF PAPAGAYO 
OVER THE NEXT COUPLE OF DAYS. WINDS WILL PEAK EACH NIGHT NEAR 25 
KT DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE ADDED 
COMPONENT OF NOCTURNAL DRAINAGE FLOW...THEN WILL DIMINISH BELOW 
25 KT DURING THE AFTERNOON AND EARLY EVENING HOURS. 

W OF 110W...
A DEEP LAYER TROUGH EXTENDS N TO S ALONG 125W N OF 
25N...DRIFTING EASTWARD. AN ASSOCIATED WEAK COLD FRONT EXTENDING 
FROM OFF NORTHERN CALIFORNIA TO 35N125W TO 32N135W WILL PUSH SE 
AND DELIVER AN AREA OF 20 TO 25 KT WINDS TO THE DISCUSSION AREA 
N OF 28N BETWEEN 125W AND 130W BY LATE SAT...BEFORE SHIFTING 
EASTWARD THROUGH NORTHERN BAJA AND THE NORTHERN GULF OF 
CALIFORNIA THROUGH LATE SUN. 

1029 MB HIGH PRES BUILDING N OF THE FRONT HAS TIGHTENED THE PRES 
GRADIENT OVER THE TROPICAL WATERS...ALLOWING A RESURGENCE OF 20 
TO 25 KT TRADE WINDS FROM 10N TO 22N W OF 120W...AS NOTED ON A 
1846 UTC ASCAT PASS. A DEEP LAYER TROUGH DIGGING ACROSS THE N 
CENTRAL PACIFIC INTO THE NE PACIFIC THIS WEEKEND WILL FORCE THE 
SURFACE HIGH PRES SOUTHWARD TO NEAR 30N135W BY LATE SAT. AT THE 
SAME TIME...A SHORTWAVE TROUGH WILL DIG SE IN THE NW FLOW ALOFT 
AND COME INTO PHASE WITH THE DEEP LAYER TROUGH ALONG 125W N OF 
25N. THIS WILL ALLOW A MODEST TROUGH TO MAINTAIN ALONG THE ITCZ 
NEAR 120W. THE AREA OF 20 TO 25 KT WINDS WILL SPREAD SOMEWHAT 
BETWEEN THE TROUGH AND THE HIGH PRES PUSHING SOUTHWARD THROUGH 
SUN.

MEANWHILE NW SWELL WITH 12 TO 16 SECOND PERIODS WILL SWEEP TO 
THE SOUTHEAST OVER MUCH OF THE AREA W OF 110W...MIXING WITH THE 
FRESH NE SWELL IN THE AREA OF 20 TO 25 KT TRADE WINDS. 

$$
CHRISTENSEN