000
AXPZ20 KNHC 240935
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT DEC 24 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 07N95W. THE ITCZ 
AXIS EXTENDS FROM 07N95W TO 10N124W TO BEYOND 07N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WAS NOTED WITHIN 30 NM 
EITHER OF MONSOON TROF AXIS BETWEEN 95W AND 100W. SCATTERED 
MODERATE CONVECTION WAS NOTED WITHIN 90 NM OF ITCZ AXIS BETWEEN 
110W AND 115W.

...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. A 0350 
UTC ASCAT PASS SHOWED WINDS TO 30 KT OVER THE SOUTHERN PORTIONS 
OF THE GULF. GIVEN THE CURRENT STRENGTH OF THE HIGH PRES TO THE 
NORTH AND THE TIGHT PRES GRADIENT STILL IN PLACE...WINDS TO GALE 
FORCE ARE LIKELY ONGOING THIS MORNING. THE STRONG GRADIENT FLOW 
ACROSS THE GULF OF CALIFORNIA IS SPILLING OVER SOME OF THE GAPS 
ON THE BAJA PENINSULA...WITH CERTAIN AREAS OF WINDS TO 25 KT 
ALONG THE PACIFIC COAST OF BAJA THIS MORNING. THE RIDGING OVER 
THE GREAT BASIN WILL WEAKEN TODAY AS A SHORT WAVE TROUGH 
MIGRATES N OF THE RIDGE THROUGH THE NORTHERN ROCKIES. THE 
WEAKENING HIGH PRESSURE WILL RESULT IN DIMINISHING WINDS OVER 
THE GULF OF CALIFORNIA...BELOW GALE FORCE BY SAT MORNING...AND 
FURTHER DIMINISH TO 25 KT 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. A 0408 UTC ASCAT PASS SHOWED WINDS ALREADY 
UP TO 25 KT THROUGH THE GULF OF TEHUANTEPEC. IN 
ADDITION...LATEST WIND OBSERVATIONS FROM SALINA CRUZ ON THE 
PACIFIC COAST ARE REACHING 25 KT...AN INDICATION OF HIGHER WINDS 
OVER ADJACENT WATERS. WINDS ARE EXPECTED TO REACH GALE FORCE 
THIS MORNING 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 LATE SUN AND PERSISTING 
THROUGH MON AFTERNOON. 

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.

1036 MB HIGH PRES IS CENTERED N OF THE AREA NEAR 36N127W. A 
SURFACE TROUGH PERSISTS FURTHER SOUTH NEAR THE ITCZ FROM 13N125W 
TO 08N128W. THE PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE TO 
THE NORTH AND TROUGH TO THE SOUTH IS IS MAINTAINING A LARGE AREA 
OF FRESH TO STRONG TRADEWINDS OVER MUCH OF THE AREA N OF 10N W 
OF 110W. THE TROUGH WILL MIGRATE W OF OF 140W THROUGH 72 
HOURS...ALLOWING THE FRESH TO STRONG TRADEWINDS TO PERSIST. A 
0530 UTC ASCAT PASS SHOWS GENERALLY 20 KT WINDS N OF THE TROUGH. 
GFS MODEL INITIALIZES A LITTLE TOO STRONG...AND INDICATES WINDS 
TO 30 KT BY LATE SUN. FORECAST FAVORS WEAKER AND BETTER 
INITIALIZED ECMWF AND UKMET SOLUTIONS OVER THE STRONGER GFS WITH 
WINDS TO 25 KT GENERALLY FROM 10N TO 15N W OF 130W. THE AREA OF 
HIGH PRESSURE WILL REMAIN N OF THE AREA THROUGH SUN 
NIGHT...MAINTAINING THIS AREA OF TRADEWINDS... WITH SEAS 
BUILDING TO 13 FT. 

$$
CHRISTENSEN