000
AXPZ20 KNHC 232129
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI DEC 23 2011

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.

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

THE MONSOON TROUGH AXIS EXTENDS FROM 08N83W TO 07N94W. THE ITCZ 
AXIS EXTENDS FROM 07N94W TO 09N107W TO BEYOND 08N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WAS NOTED WITHIN 120 NM N OF 
THE ITCZ AXIS BETWEEN 95W AND 102W. SCATTERED MODERATE 
CONVECTION WAS NOTED WITHIN 60 NM EITHER SIDE OF ITCZ AXIS 
BETWEEN 106W AND 112W. SCATTERED MODERATE CONVECTION WAS NOTED 
WITHIN 90 NM OF ITCZ AXIS W OF 125W.

...DISCUSSION...

GULF OF CALIFORNIA...STRONG HIGH PRESSURE IN EXCESS OF 1040 MB 
PREVAILS OVER THE GREAT BASIN REGION PROMOTING STRONG NORTHERLY 
FLOW OVER THE ENTIRE LENGTH OF THE GULF OF CALIFORNIA. GALE 
FORCE WINDS HAVE BEEN CONFIRMED FROM EARLIER ASCAT PASS. THE 
STRONG GRADIENT FLOW ACROSS THE GULF OF CALIFORNIA WILL SPILL 
OVER SOME OF THE GAPS ON THE BAJA PENINSULA...WITH CERTAIN AREAS 
OF WINDS TO 30 KT ALONG THE PACIFIC COAST OF BAJA THROUGH THE 
OVERNIGHT HOURS. THE RIDGING OVER THE GREAT BASIN WILL WEAKEN 
SLIGHTLY AS A SHORT WAVE TROUGH MIGRATES N OF THE RIDGE THROUGH 
THE NORTHERN ROCKIES...ALLOWING WINDS OVER THE GULF OF 
CALIFORNIA TO DIMINISH BELOW GALE FORCE BY SAT MORNING...AND 
FURTHER DIMINISH LATE SAT AND SUN. 

GULF OF TEHUANTEPEC...DENSE COLD AIR BEHIND THE COLD FRONT OVER 
THE GULF OF MEXICO IS PUSHING THROUGH THE CHIVELA PASS INTO THE 
GULF OF TEHUANTEPEC WITH NEAR GALE WINDS NOTED. WINDS ARE 
EXPECTED TO REACH GALE FORCE OVERNIGHT AS HIGH PRES BUILDS INTO 
THE SOUTHERN PLAINS...WHICH WILL INCREASE THE WINDS FUNNELING 
INTO THE GULF OF TEHUANTEPEC. WINDS WILL DIMINISH BELOW GALE 
FORCE BY SAT AFTERNOON AS THE DENSER AIR OVER THE GULF OF MEXICO 
MODIFIES REDUCING THE WINDS FUNNELING THROUGH THE CHIVELA PASS. 
ANOTHER SURGE OF COLD AIR WILL REACH THE BAY OF CAMPECHE 
SUN...INCREASING WINDS OVER THE GULF OF TEHUANTEPEC WITH WINDS 
ONCE AGAIN EXPECTED TO REACH GALE FORCE SUN NIGHT. 

GULF OF PAPAGAYO...FRESH TRADEWINDS OVER THE WESTERN CARIBBEAN 
WILL FUNNEL INTO THE GULF OF PAPAGAYO. WINDS WILL PEAK DURING 
THE EARLY MORNING HOURS WITH THE ADDITION OF NOCTURNALLY DRIVEN 
KATABATIC WINDS.

ELSEWHERE W OF 110W...HIGH PRES 1032 MB IS CENTERED N OF THE 
AREA NEAR 35N128W WITH RIDGE EXTENDING SE TO NEAR 17N106W. THE 
PRESSURE GRADIENT BETWEEN THIS AREA OF HIGH PRESSURE AND LOWER 
PRESSURE IN THE VICINITY OF THE ITCZ IS MAINTAINING A LARGE AREA 
OF FRESH TO STRONG TRADEWINDS AS DEPICTED BY THE LATEST 18 UTC 
ASCAT PASS. THE AREA OF HIGH PRESSURE WILL REMAIN N OF THE AREA 
THROUGH SUN AFTERNOON...MAINTAINING THIS AREA OF TRADEWINDS... 
WITH SEAS BUILDING TO 13 FT. 

$$
AL