000
AXPZ20 KNHC 231712 AAA
TWDEP 

TROPICAL WEATHER DISCUSSION...UPDATE   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1715 UTC MON JAN 23 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

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

MONSOON TROUGH FROM 07N78W TO 05N80W TO 05N90W TO 03N100W. ITCZ 
FROM 03N100W TO 06N130W TO 04N140W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION FROM 07N TO 10N BETWEEN 125W AND 133W.

...DISCUSSION...

A VIGOROUS MID TO UPPER LEVEL SHORT WAVE TROUGH IS DIGGING INTO 
SOUTHERN CALIFORNIA...COMING INTO PHASE WITH ANOTHER MID TO 
UPPER TROUGH FROM NORTHERN BAJA CALIFORNIA TO 20N118W. AN 
ASSOCIATED COLD FRONT EXTENDS FROM CENTRAL CALIFORNIA TO 
28N130W. WHILE FRESH TO STRONG NW WINDS ARE NOTED IN 
SCATTEROMETER DATA N OF 30N BEHIND THE FRONT...GENERALLY LIGHT 
NW FLOW IS NOTED OVER THE DISCUSSION AREA BEHIND THE FRONT DUE 
TO THE PROXIMITY OF 1025 MB SURFACE HIGH CENTERED NEAR 29N140W. 
SHIP AND SCATTEROMETER DATA SHOW 20 KT NW TO N PERSISTING 
BETWEEN THE SURFACE RIDGE ALONG 29N AND THE NORTHERN COAST OF 
BAJA CALIFORNIA.

THE SHORT WAVE TROUGH WILL AMPLIFY AS IT SHIFTS EAST THROUGH 
SOUTHERN CALIFORNIA OVERNIGHT...RESULTING IN THE FRESH NW FLOW 
EXPANDING OVER MUCH OF THE AREA N OF 28N E OF 125W. THE 
TIGHTENING SURFACE GRADIENT WILL ALSO RESULT IN FRESH SW TO W 
FLOW OVER THE NORTHERN GULF OF CALIFORNIA AS THE FRONT MOVES 
INTO SOUTHERN CALIFORNIA AND NORTHERN BAJA OVERNIGHT. NW FLOW 
WILL INCREASE DOWN THE LENGTH OF THE GULF OF CALIFORNIA THROUGH 
MID WEEK AS STRONG BETWEEN DEEP LAYER TROUGHING TO THE EAST OVER 
NORTH CENTRAL MEXICO...AND STRONG HIGH PRES BUILDING OFF THE 
CALIFORNIA COAST. THIS WILL ALSO RESULT IN A LARGE AREA OF FRESH 
TO STRONG N TO NE FLOW SETTING UP ALONG THE CALIFORNIA 
COAST...AND PUSHING INTO THE WATERS N OF 20N W OF 130W.

MEANWHILE FRESH TO STRONG NE TRADES PERSIST S OF THE SURFACE 
RIDGE...FROM THE ITCZ TO GENERALLY 20N W OF 120W. SHIP AND 
ALTIMETER DATA CONTINUE TO INDICATE NW SWELL PROPAGATING THROUGH 
MUCH OF THE AREA W OF 115W...MIXING WITH SHORTER PERIOD NE SWELL 
IN THE AREA OF FRESH TO STRONG TRADE WINDS. 

AN UPPER CYCLONIC CIRCULATION IS BECOMING CUT OFF NEAR 11N135W. 
THE MAIN SENSIBLE WEATHER IMPACT AT THE SURFACE IS THE 
INTERACTION OF UPPER DIVERGENT FLOW E OF THIS SYSTEM WITH LOWER 
LEVEL TRADE WIND CONVERGENCE...RESULTING IN SCATTERED MODERATE 
TO ISOLATED STRONG CONVECTION FROM 07N TO 10N BETWEEN 125W AND 
133W.

GULF OF PAPAGAYO...FRESH TO STRONG WINDS IN THE SW CARIBBEAN 
FUNNELING THROUGH NICARAGUA AND COSTA RICA IS SPREADING ACROSS 
THE GULF OF PAPAGAYO AND THE PACIFIC FROM 10N TO 12N E OF 90W. 
THIS WINDS WILL PERSIST THROUGH MID WEEK...WITH STRONGEST FLOW 
DURING THE LATE OVERNIGHT AND EARLY MORNING HOURS.

LOOKING AHEAD...A COLD FRONT WILL MOVE THROUGH THE WESTERN GULF 
OF MEXICO WED NIGHT THROUGH THU...FOLLOWED BY STRONG NORTHERLY 
WINDS. THESE WINDS WILL PUSH THROUGH THE ISTHMUS OF TEHUANTEPEC 
THU...AND WILL POSSIBLY DELIVER GAP FLOW TO GALE FORCE INTO THE 
THE GULF TEHUANTEPEC BY LATE THU. LATEST GFS GUIDANCE SHOWS THIS 
BARELY REACH GALE FORCE AND BEING FAIRLY SHORT LIVED AND ENDING 
EARLY FRI. THIS IS PLAUSIBLE SINCE THIS IS A FAIRLY PROGRESSIVE 
PATTERN AND THE COLD AIR ADVECTION WILL BE LIMITED. A STRONGER 
REINFORCING PUSH IS EXPECTED LATER OVER THE WEEKEND.

$$
CHRISTENSEN