000
AXPZ20 KNHC 030335
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC FRI JAN 3 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...SPECIAL FEATURE...                                         
GULF OF TEHUANTEPEC STORM WARNING...A COLD AIR MASS RACING 
THROUGH THE CHIVELA PASS THIS EVENING WILL BRING 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 AFTERNOON 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 05N104W...THEN ITCZ 
AXIS TO 09N129W TO 09N140W. SCATTERED MODERATE CONVECTION WITHIN 
60 NM OF AXIS BETWEEN 123W AND 132W.

...DISCUSSION...                                               
DIFFLUENT FLOW ALOFT IS ENHANCING VERTICAL MOTION NEAR THE ITCZ 
PRODUCING EMBEDDED SHOWERS AND MULTI-LAYERED CLOUDS OVER MUCH OF 
FORECAST REGION W OF 125W. THE UPPER PATTERN IS BECOMING MORE 
PROGRESSIVE. THIS AREA OF DIFFLUENCE ALOFT WILL SHIFT EASTWARD 
ALONG THE ITCZ DURING THE NEXT 1-2 DAYS. 

A 1025 MB SUBTROPICAL HIGH NEAR 35N131W ANCHORS A WEAK RIDGE N 
OF 18N BETWEEN 110W AND 140W. MODERATE-FRESH TRADE WINDS PREVAIL 
S OF RIDGE W OF 115W. DECAYING LONG-PERIOD NW SWELL IN WESTERN 
WATERS IS MIXING WITH NE WIND WAVES ASSOCIATED WITH THE TRADES 
TO PRODUCE AN AREA 8-10 FT SEAS FROM 09N-16N W OF 121W. A NEW 
BATCH OF NW SWELL IS SWEEPING INTO NW WATERS. A STRONG COLD 
FRONT WILL BRUSH PAST NW PORTION SAT. FRESH S WINDS ARE EXPECTED 
AHEAD OF THE FRONT SAT EVENING...WITH SEAS TO 8-10 FT NW PART.

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