000
AXPZ20 KNHC 010327
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN JAN 01 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...MONSOON 
TROUGH AXIS FROM 07N74W TO LOW PRES NEAR 05N78W 1007 MB TO 
04N87W...WHERE IT TRANSITIONS TO ITCZ...CONTINUING ON TO 01N93W 
TO 07N110W TO 08N124W TO 04.5N133W TO BEYOND 06N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 150 NM N 
QUADRANT OF LOW PRES NEAR 05N78W. SCATTERED TO NUMEROUS MODERATE 
TO STRONG CONVECTION WITHIN 120 NM S AND 210 NM N OF AXIS FROM 
116W TO 128W.

...DISCUSSION...

AT UPPER LEVELS...A LARGE AND POWERFUL MIDDLE TO UPPER LEVEL 
LONG WAVE TROUGH WAS APPROACHING NW PORTIONS TONIGHT...GRADUALLY 
SHIFTING E ACROSS THE CENTRAL N PACIFIC...CURRENTLY LOCATED N OF 
25N WITH MEAN AXIS ALONG 151W. THIS FEATURE IS INDUCING A BROAD 
HIGH AMPLITUDE UPPER RIDGE ACROSS THE AREA N OF 28N CENTERED 
ALONG ABOUT 122W. AN OLD CUT OFF DEEP LAYERED CYCLONE ACROSS SW 
PORTIONS OF THE AREA A FEW DAYS AGO HAS WEAKENED AND SHIFTED EWD 
DURING THE PAST 24 HOURS...NOW A SHORTWAVE TROUGH ALONG 137W 
FROM 05N TO 22N. THE LONG WAVE TROUGH WILL MOVE E TO NEAR 140W 
DURING THE NEXT 24 HOURS...AND NUDGE THE ENTIRE UPPER PATTERN 
ACROSS THE AREA EWD IN TURN. 

STRONG HIGH PRESSURE THAT HAD BEEN CENTERED N OF THE AREA THE 
PAST COUPLE OF DAYS HAS WEAKENED SIGNIFICANTLY...WITH THE 
PRIMARY HIGH PRESSURE NOW 1023 MB CENTERED FURTHER NE NEAR 
39N126W. WITH THIS AREA OF HIGH PRESSURE WEAKENING...THE ZONE OF 
FRESH TRADEWINDS PREVAILING JUST 48 HOURS AGO HAS DIMINISHED 
CONSIDERABLY...NOW LIMITED TO THE AREA FROM 06N TO 12N W OF 133W 
AND FROM 07N TO 10W BETWEEN 124W AND 133W. ALTHOUGH THE WIND 
FIELD ACROSS THIS REGION HAS WEAKENED...SATELLITE IMAGERY 
CONTINUES TO SHOW WIDESPREAD CONVECTION MENTIONED ABOVE 
OCCURRING ACROSS THIS AREA. A STRONG EQUATORIAL UPPER JET 
OCCURRING BETWEEN THE SHORTWAVE TROUGH AND AN UPPER CYCLONE S OF 
THE EQUATOR ALONG 08S130W IS AIDING IN PRODUCING STRONG LOW TO 
MID LEVEL CONVERGENCE BETWEEN 118W AND 130W...LEADING TO THE 
PERSISTENT CONVECTION. AS THE UPPER PATTERN AND ASSOCIATED 
EQUATORIAL JET SHIFT E DURING THE NEXT 24 HOURS...LOOK FOR THE 
MAIN PORTION OF THE ACTIVE CONVECTION TO SHIFT E OF 120W. 

THE HIGH PRESSURE RIDGE WILL SHIFT EASTWARD ENABLING A SURFACE 
COLD FRONT TO ENTER THE FAR NW PART OF THE AREA ON SUN. SW WINDS 
WILL FRESHEN OVER THE FAR NW PART OF THE AREA AHEAD OF THE COLD 
FRONT TONIGHT...MAINLY N OF 28N W OF 135W. THE COLD FRONT WILL 
RAPIDLY WEAKEN AND DISSIPATE BY MONDAY. HOWEVER...AN EXPANSIVE 
WIND FIELD BEHIND THE FRONT HAS GENERATED LARGE LONG PERIOD NW 
SWELL THAT WILL PROPAGATE INTO THE AREA...WITH COMBINED SEAS AS 
HIGH AS 20 FT EXPECTED TO PEAK MON MORNING ACROSS THE FAR NW 
CORNER OF THE AREA. 

GULF OF PAPAGAYO...
FRESH TO STRONG TRADEWINDS OVER THE WESTERN CARIBBEAN CONTINUE 
TO FUNNEL THROUGH THE NICARAGUA MOUNTAINS INTO THE GULF OF 
PAPAGAYO. WINDS WILL PEAK AT 20-25 KT DURING THE LATE NIGHT AND 
EARLY MORNING HOURS WITH THE ADDED COMPONENT OF NOCTURNALLY 
DRIVEN KATABATIC WINDS. DOWNSTREAM SEAS WILL GENERALLY RUN 6-8 
FT BRIEFLY BUILDING TO 9 FT AFTER PEAK WIND FLOW.

GULF OF TEHUANTEPEC...
A WEAK TROUGH OVER THE YUCATAN PENINSULA JUST E OF THE BAY OF 
CAMPECHE COMBINED WITH HIGH PRESSURE OVER EASTERN MEXICO IS 
CREATING LOCALIZED NORTHERLY WINDS WHICH ARE FUNNELING THROUGH 
THE CHIVELA PASS RESULTING IN FRESH WINDS OVER THE GULF OF 
TEHUANTEPEC. WINDS FUNNELING THROUGH THE CHIVELA PASS WILL 
INCREASE OVERNIGHT AND SUN AHEAD OF A STRONG COLD FRONT THAT 
WILL SINK SE ACROSS THE GULF OF MEXICO. WINDS ARE EXPECTED TO 
REACH GALE FORCE SUN EVENING AND PEAK AROUND 45 KT MON...WITH 
MAXIMUM SEAS BUILDING TO NEAR 18 FT MON AFTERNOON.
     
GULF OF PANAMA...
FRESH TO STRONG NE WINDS OVER THE SW CARIBBEAN WILL FUNNEL INTO 
ACROSS PANAMA...AND MAINTAIN FRESH 20 KT NLY WINDS OVER THE GULF 
OF PANAMA THROUGH AT LEAST MONDAY MORNING. THESE WINDS WILL 
COMBINE WITH MONSOONAL SW WINDS OFF THE PACIFIC COASTS OF 
EQUATORIAL COLOMBIA AND PERU...TO PRODUCE PERIODS OF ACTIVE 
CONVECTION.

GULF OF CALIFORNIA...
THE WEAKENED HIGH PRES CENTER N OF THE AREA IS SHIFTING EWD AND 
APPROACHING THE COAST OF CENTRAL CALIFORNIA. AS THIS 
OCCURS...SUFFICIENT PRES GRADIENT WILL ENSUE BETWEEN THE HIGH 
AND LOW PRES ALONG THE SIERRA MADRES OCCIDENTALES...LEADING TO 
FRESH NLY WINDS DOWN THE GULF OF CALIFORNIA STARTING SUN 
MORNING. WINDS COULD INCREASE TO 20-25 KT DURING THE MIDDLE OF 
THE WEEK AS STRONGER HIGH PRES MOVES INTO NW PORTIONS OF THE 
DISCUSSION AREA.

$$
STRIPLING