000
AXPZ20 KNHC 022130
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC THU JAN 2 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURE...                                         
GULF OF TEHUANTEPEC STORM WARNING...A COLD AIR MASS WILL RACE 
THROUGH CHIVELA PASS THIS EVENING...BRINGING GALE FORCE WINDS 
TONIGHT...AND STORM FORCE WINDS EARLY FRI. SEAS WILL RAPIDLY 
BUILD FROM 10 FT TO 20 FT FRI MORNING. WARM OCEAN TEMPERATURES 
SHOULD HELP MIX THE STRONG WINDS WITHIN THE COLD AIR ALOFT DOWN 
TO THE SURFACE OVER THE GULF OF TEHUANTEPEC. NOCTURNAL DRAINAGE 
FLOW WILL ALSO ENHANCE THE WINDS OVERNIGHT. STORM FORCE WINDS 
ARE EXPECTED TO END FRI MORNING WITH WINDS GRADUALLY DIMINISHING 
BELOW GALE FORCE SAT MORNING AS THE PRESSURE GRADIENT WEAKENS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
THE MONSOON TROUGH EXTENDS FROM 06N77W TO 06N87W TO 05N103W... 
THEN ITCZ TO 09N133W TO 08N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITHIN 60 NM N OF AXIS BETWEEN 125W AND 132W.

...DISCUSSION...                                               
STRONGLY DIFFLUENT FLOW ALOFT IS ENHANCING LIFT NEAR THE ITCZ 
OVER WESTERN FORECAST WATERS. EMBEDDED SHOWERS AND MULTI-LAYERED 
CLOUDS EXTEND OVER MUCH OF FORECAST REGION W OF 125W. THE UPPER 
PATTERN IS BECOMING MORE PROGRESSIVE. THE AREA OF DIFFLUENCE 
ALOFT SUPPORTING THIS LIFT AND ENHANCING THE CONVECTION WILL BE 
SHIFTING EASTWARD ALONG THE ITCZ DURING THE NEXT 1-2 DAYS. 

A 1025 MB SUBTROPICAL HIGH NEAR 35N131W ANCHORS A RIDGE N OF 15N 
BETWEEN 110W AND 140W. FRESH TRADE WINDS FOUND FROM 08N TO 20N W 
OF 115W. DECAYING LONG-PERIOD NW SWELL DOMINATES WESTERN WATERS 
AND MIXING WITH NE WIND WAVES ASSOCIATED WITH THE TRADES. A NEW 
BATCH OF NW SWELL ASSOCIATED WITH A COLD FRONT APPROACHING THE 
AREA IS SWEEPING INTO NW WATERS. CURRENT AREA OF SEAS OVER 8 FT 
IS EXPECTED TO SHRINK W OF 120W THROUGH FRI THEN SUBSIDE BELOW 8 
FT BY EARLY SAT. A NEGATIVELY TILTED UPPER TROUGH WILL APPROACH 
NW WATERS SAT MORNING...AND A STRONG COLD FRONT WILL BRUSH PAST 
NW PORTION. FRESH S WINDS ARE EXPECTED AHEAD OF THE FRONT SAT.

STRONG TRADE WIND FLOW IN THE SW CARIBBEAN AND LOCAL OVERNIGHT 
DRAINAGE FLOW WILL CONTINUE TO GENERATE 20-25 KT WINDS DURING 
PEAK DRAINAGE FLOW THROUGH SAT. SEAS ARE EXPECTED TO REACH 8 FT 
EARLY SAT MORNING.
 
$$ 
MUNDELL