000
AXPZ20 KNHC 221006
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

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

ITCZ AXIS FROM 06N116W TO 01.5N136W. SCATTERED MODERATE 
CONVECTION NOTED WITHIN 90 NM OF AXIS BETWEEN 110W AND 120W.

...DISCUSSION...

THE UPPER RIDGE ACROSS N PORTIONS OF THE AREA CONTINUES TO 
WEAKEN AS IT IS FORCED EASTWARD TO A LONGWAVE TROUGH 
STRENGTHENING ACROSS THE NE PACIFIC. THE SHORTWAVE UPPER RIDGE 
WAS N OF 20N CENTERED ALONG 116W...AND SANDWICHED BETWEEN A DEEP 
LAYERED CUT OFF LOW ACROSS THE CENTRAL U.S. CENTERED OVER 
OKLAHOMA...A 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 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...EXTENDING FROM 30N134W TO 
28N140W. RECENT SCATTEROMETER IMAGERY HAS DEPICTED A NARROW ZONE 
150 NM WIDE OF NLY WINDS 20-25 KT LOCATED N OF THE FRONT...AND 
LOCATED ALONG THE LEADING EDGE OF A PULSE OF NWLY SWELL WHERE 
SEAS WERE RUNNING 8-9 FT. THIS FRONT WILL MOVE SE AND GRADUALLY 
DISSIPATE IN THE NEXT 24-36 HOURS...WITH A SECOND STRONGER FRONT 
AND VERY HIGH SEAS MOVING INTO THIS NW CORNER BY 48 HOURS. HIGH 
PRES TO THE E OF THIS FRONT HAS COLLAPSED...LEAVING WEAKENING 
ANTICYCLONIC FLOW S AND SE OF THE FRONT...WITH 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 FALLEN BELOW 
20 KT BASED ON RECENT SCATTEROMETER PASSES. SUFFICIENT PRES 
GRADIENT PREVAILS TO THE S OF THE RIDGE TO PRODUCE AN AREA OF 
FRESH NELY TRADEWINDS FROM 06N TO 17N W OF 134W...WHERE SEAS ARE 
8-10 FT IN MIXED NE AND NW SWELL. AS THE SECOND COLD FRONT 
APPROACHES THE AREA DURING THE NEXT TWO DAYS...THE RIDGE WILL 
WEAKEN FURTHER AND ASSOCIATED FRESH TRADEWINDS 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 PERSISTENT SURFACE TROUGH EXTENDS FROM JUST SW OF 
THE GULF OF PAPAGAYO SW TO 01N102W. CONVERGENCE OCCURRING TO THE 
SE OF THIS TROUGH CONTINUES TO PRODUCE PULSES OF 
CONVECTION...WHICH HAS WEAKENED OVERNIGHT. AN ELONGATED 
CONVERGENCE ZONE S OF THE SURFACE RIDGE ALSO CONTINUES TO 
PRODUCE A NARROW 150 NM WIDE ZONE OF LOW AND MIDDLE CLOUDS WITH 
ISOLATED TO SCATTERED EMBEDDED MODERATE CONVECTION. LIGHT SE 
WINDS TO THE S OF THIS ZONE ARE FLOWING FROM THE SOUTHERN 
HEMISPHERE...AND THIS CONVERGENCE ZONE IS NOW BEING ANALYZED AS 
THE ITCZ.  

TRADEWINDS 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 NELY WINDS 
PULSING TO 20-25 KT DURING THE OVERNIGHT HOURS ARE EXPECTED TO 
RETURN TO THE GULF OF PAPAGAYO TONIGHT THROUGH FRI. 

$$
STRIPLING