000
AXPZ20 KNHC 221602
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU MAR 22 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 
1545 UTC.

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

ITCZ AXIS EXTENDS FROM 08N110W TO 06N123W TO 03N132W TO 02N140W.
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF AXIS BETWEEN
113W-117W.

...DISCUSSION...

THE UPPER RIDGE ACROSS N PORTIONS OF THE AREA CONTINUES TO 
WEAKEN AS IT IS FORCED EASTWARD IN RESPONSE TO A LONGWAVE TROUGH 
STRENGTHENING ACROSS THE NE PACIFIC. THE SHORTWAVE UPPER RIDGE 
WAS N OF 20N CENTERED ALONG 114W...AND SANDWICHED BETWEEN A DEEP 
LAYERED CUT-OFF LOW ACROSS THE CENTRAL U.S. CENTERED OVER 
OKLAHOMA...A SHORTWAVE TROUGH TO ITS W N OF 19N ALONG 125W. 
STRONG ZONAL FLOW PREVAILED S OF THESE FEATURES TO THE 
EQUATOR...WITH NWLY FLOW ALOFT W OF 130W.   

A SHORTWAVE TROUGH MOVING NE THROUGH THE E SIDE OF THE LONGWAVE
TROUGH ACROSS THE NE PACIFIC SUPPORTS A COLD FRONT THAT HAS 
RECENTLY MOVED INTO THE NW CORNER OF THE AREA. AS OF 12 UTC IT 
EXTENDS FROM 32N128W TO W OF THE DISCUSSION AREA AT 27N140W. BOTH
OSCAT AND ASCAT DATA FROM LAST NIGHT SHOWED N-NE WINDS OF 
MOSTLY 20 KT TO THE NW OF THE COLD FRONT. SEAS OF 8-10 FT IN NW
SWELLS ARE PRESENT NW OF THE FRONT. THE FRONT WILL MOVE SE AND 
GRADUALLY DISSIPATE THROUGH THE NEXT 24-30 HOURS...WITH A 
SECOND AND STRONGER COLD FRONT MOVING INTO THE NW CORNER 
BEGINNING BY EARLY FRI EVENING. VERY LARGE SEAS OF POSSIBLE
RANGES IN THE 10-16 FT IN NW SWELLS ARE FORECAST BY WAVEWATCH
MODEL GUIDANCES TO FOLLOW IN BEHIND THE FRONT THROUGH SAT.
ALSO...POSSIBLE GALE FORCE WINDS IN VERY STRONG NW COLD AIR FLOW
MAY SKIRT THE FAR N/CENTRAL WATERS ON SAT IN THE WAKE OF THE 
FRONT.

HIGH PRES TO THE E OF THE PRESENT COLD FRONT HAS COLLAPSED 
LEAVING WEAKENING ANTICYCLONIC FLOW S AND SE OF THE FRONT WITH A 
RIDGE EXTENDING TO 23N115W. THE PRES GRADIENT TO THE E OF THIS 
RIDGE...ALONG THE W COAST OF BAJA CALIFORNIA AND THROUGH THE 
GULF OF CALIFORNIA HAS WEAKENED CONSIDERABLY DURING THE PAST 
24-48 HOURS...AND WINDS ACROSS BOTH OF THESE AREAS HAVE LESSEN 
TO LESS THAN 20 KT. SUFFICIENT PRES GRADIENT PREVAILS TO THE S 
OF THE RIDGE TO PRODUCE AN AREA OF FRESH NELY TRADE WINDS FROM 
06N TO 17N W OF 134W WHERE SEAS ARE TO 9 FT. AS THE SECOND COLD 
FRONT APPROACHES AND MOVES INTO THE AREA DURING THE NEXT COUPLE 
OF DAYS...THE RIDGE WILL RESPOND BY WEAKENING FURTHER. THE FRESH
TRADE WINDS WILL GRADUALLY SHRINK IN AREAL COVERAGE AND SHIFT W 
OF THE AREA.  

E OF 110W..LIGHT TO MODERATE WINDS PREVAIL AT GENERALLY LESS 
THAN 15 KT. A RATHER PERSISTENT SURFACE TROUGH EXTENDS FROM JUST 
SW OF THE GULF OF PAPAGAYO SW TO NEAR 01.5N102W. CONVERGENCE 
OCCURRING TO THE SE OF THIS TROUGH CONTINUES TO PRODUCE PULSES 
OF CONVECTION...WHICH HAS WEAKENED SINCE LATE NIGHT. THE 
CONVECTION MAY REDEVELOP AGAIN THIS AFTERNOON INTO TONIGHT.

TRADE WINDS HAVE WEAKENED ACROSS THE WESTERN CARIBBEAN AND ARE 
SOMEWHAT DIFFLUENT APPROACHING THE CENTRAL AMERICAN COASTS. GAP 
WINDS SPILLING ACROSS CENTRAL AMERICA AND INTO THE EASTERN 
PACIFIC REMAIN LIGHT TONIGHT AND BELOW 20 KT. TYPICAL NE-E WINDS 
OF AROUND 20 KT ARE EXPECTED FUNNEL OUT THROUGH THE GULF OF 
PAPAGAYO BEGINNING LATE TONIGHT AND INTO EARLY FRI WITH LITTLE 
CHANGE OR POSSIBLE WEAKENING EXPECTED IN SAT.

N WINDS OF 20 KT ARE EXPECTED TO SPILL THROUGH THE GULF OF 
PANAMA FROM THE SW CARIBBEAN SEA BEGINNING EARLY TONIGHT WITH
LITTLE CHANGE THROUGH FRI...THEN DROPPING TO LESS THAN 20 KT
BY EARLY SAT AS THE CARIBBEAN TRADES SLACKEN.

$$
AGUIRRE