000
AXPZ20 KNHC 012136
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC TUE JAN 1 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...ASCAT SCATTEROMETER PASS 
OVER THE REGION AT 1630 UTC SHOWED SMALL AREA OF 20-30 KT WINDS 
N OF 15N IN THE GULF OF TEHUANTEPEC. THE PRES GRADIENT OVER S 
MEXICO WILL CONTINUE TO WEAKEN TONIGHT AS LOW PRES IN THE W GULF 
OF MEXICO LIFTS NORTH...ALLOWING WINDS TO DIMINISH THROUGH THU 
EVENING. A STRONG COLD FRONT BARRELS THROUGH CHIVELA PASS THU. 
STORM FORCE WINDS ARE EXPECTED IN THE REGION STARTING THU NIGHT 
AND CONTINUE THROUGH FRI MORNING.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
MONSOON TROUGH EXTENDS FROM 06N77W TO 07N85W TO 05N100W...THEN 
ITCZ AXIS TO 08N130W TO 06N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITHIN 30 NM OF AXIS BETWEEN 128W AND 137W. 

...DISCUSSION...                                                
A HIGHLY AMPLIFIED LONG-WAVE UPPER PATTERN CONTINUES OVER THE 
FORECAST AREA. A TROUGH ALONG 149W EXTENDS SOUTHWARD TO 10N. A 
TROUGH BETWEEN 104W-109W EXTENDS DEEP INTO THE TROPICS TO NEAR 
THE EQUATOR. BETWEEN THE TWO TROUGHS IS A RIDGE ALONG 130W. 
DIVERGENT FLOW E OF THE TROUGH ALONG 149W IS CRESTING OVER THE 
RIDGE ALONG 130W...PRODUCING A LARGE AREA OF MID/UPPER LEVEL 
CLOUDS AND EMBEDDED SHOWER ACTIVITY N OF 07N W OF 125W. A PLUME 
OF MID LEVEL MOISTURE IS STREAMING NORTHEASTWARD AHEAD OF THE 
TROUGH AXIS ALONG 109W INTO SOUTH-CENTRAL MEXICO. A WEAK SURFACE 
RIDGE ANCHORED BY 1026 MB HIGH CENTERED NEAR 33N131W PREVAILS 
OVER THE NORTHERN PART OF THE AREA N OF 15N BETWEEN 110W-140W. 
MODERATE TO FRESH TRADE WINDS S OF THE RIDGE ARE FOUND PRIMARILY 
FROM 08N-23N W OF 115W. DECAYING LONG-PERIOD NW SWELL DOMINATES 
WESTERN WATERS...AND MIXING WITH NE WIND WAVES ASSOCIATED WITH 
THE TRADE WINDS. STRONG TRADES IN W CARIBBEAN ARE BEING FORCED 
ACROSS MOUNTAIN GAPS INTO THE GULF OF PAPAGAYO. WINDS THERE 
PULSE TO 20-25 KT EACH MORNING ENHANCED BY MOUNTAIN DRAINAGE.

$$ 
MUNDELL