000
AXPZ20 KNHC 150913
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT DEC 15 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 09N83W TO 06N98W WHERE LOW LEVEL 
WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES TO BEYOND 
09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED 
WITHIN 120 NM N OF AXIS BETWEEN 130W AND 135W.

...DISCUSSION...

LOW PRESSURE 1013 MB IS CENTERED N OF THE AREA NEAR 33N120W WITH 
ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 30N118W EXTENDING 
TO 28N125W. HIGH PRESSURE 1031 MB IS CENTERED NEAR 33N153W WITH 
RIDGE EXTENDING SE TO NEAR 24N113W. THE PRESSURE GRADIENT 
BETWEEN THE RIDGE AND AREA OF LOW PRESSURE IS MAINTAINING FRESH 
TO STRONG W TO NW WINDS N OF THE FRONT. THE PRESSURE GRADIENT 
BETWEEN THE RIDGE AND LOWER PRESSURE IN THE VICINITY OF THE ITCZ 
IS MAINTAINING FRESH TO STRONG TRADEWINDS FROM 10N TO 22N W OF 
135W AND FROM 15N TO 20N BETWEEN 125W AND 135W. THE PRESSURE 
GRADIENT BETWEEN THE SURFACE RIDGE AND TROUGHING OVER CENTRAL 
MEXICO IS MAINTAINING FRESH TO STRONG NORTHERLY WINDS OFF THE 
COAST OF MEXICO FROM 17N TO 22N BETWEEN 105W AND 108W.

THE UPPER LEVEL TROUGH RESPONSIBLE FOR THE LOW PRESSURE CENTER 
WILL SHIFT EASTWARD OVER THE NEXT 24 HOURS. THIS WILL HELP SHIFT 
THE SURFACE LOW EASTWARD INTO SOUTHERN ARIZONA WITH ASSOCIATED 
COLD FRONT MOVING E OF THE AREA. THE SURFACE RIDGE WILL CONTINUE 
TO PREVAIL OVER THE N PART OF THE AREA OVER THE NEXT COUPLE OF 
DAYS. THIS WILL MAINTAIN THE AREA OF FRESH TO STRONG TRADEWINDS 
THROUGH THE WEEKEND.  

GAP WINDS
GULF OF TEHUANTEPEC...N WINDS HAVE DIMINISHED TO 20-25 KT AND 
EXPECTED TO FURTHER WEAKEN TODAY...BECOMING LIGHT AND VARIABLE 
BY EVENING. LOOKING AHEAD ANOTHER STRONG GAP WINDS EVENT WILL 
BE POSSIBLE LATE NEXT WEEK WITH THE POTENTIAL FOR STORM 
CONDITIONS BY FRI. 

$$
AL