000
AXPZ20 KNHC 310321
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT MAR 31 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

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

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N95W TO 
03N118W TO 04N140W. SCATTERED MODERATE CONVECTION IS FROM 04N TO 
06N BETWEEN 92W AND 96W.

...DISCUSSION...

WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL SHORTWAVE TROUGH AND 
MID-LEVEL LOW CENTERED NORTH OF THE DISCUSSION AREA NEAR 39N139W 
THAT SUPPORTS A 988 MB STORM-FORCE SURFACE LOW NEARLY COLLOCATED 
WITH THE MIDDLE TO UPPER LEVEL LOW. A COLD FRONT EXTENDS EAST OF 
THE LOW FROM 40N133W TO 32N136W TO BEYOND 29N140W. AN EARLIER 
ASCAT PASS FROM 30/1932 UTC DEPICTED 20 KT SW WINDS PRECEDING 
THE FRONT AND THESE WINDS ARE CURRENTLY CLIPPING THE FAR NW 
PORTION OF THE DISCUSSION AREA. THE 20 KT SW WINDS WILL SLIDE 
NORTH OF 30N OVERNIGHT WITH MOST OF THE INFLUENCE WITHIN THE 
HIGH SEAS FORECAST AREA SHIFTING TO 20 TO 25 KT NW TO N WINDS 
WEST OF THE FRONT. BY LATE SUNDAY AS THE FRONT IS DISSIPATING N 
OF 21N E OF 124W...AN AREA OF 25 TO 30 KT NW WINDS ARE FORECAST 
NORTH OF THE FRONT IN CLOSE PROXIMITY TO THE W COAST OF BAJA 
CALIFORNIA. FARTHER SOUTHEAST OF THE FRONT AND W OF 124W...A 
RATHER LARGE AREA OF NE TRADES WILL SETUP AS A STRONG SURFACE 
HIGH MOVES EASTWARD BEHIND THE FRONT FROM THE CENTRAL PACIFIC.

MORE IMPORTANTLY WITH THIS FRONT ARE THE SIGNIFICANT WAVE 
HEIGHTS AND NW SWELL THAT ARE FORECAST OVERTAKE THE MUCH OF THE 
AREA BY SUNDAY. WAVE HEIGHTS ARE EXPECTED TO PEAK AROUND 20 FT 
BY EARLY SUNDAY REMAINING N OF 27N. BY THE END OF THE 48 HOUR 
FORECAST PERIOD...WAVE HEIGHTS 12 FT OR ABOVE ARE EXPECTED TO BE 
NW OF A LINE FROM 30N1115W TO 21N124W TO 16N140W.

ELSEWHERE...A POSITIVELY TILTED UPPER LEVEL TROUGH LIES OVER THE 
FORECAST AREA FROM WEST TEXAS THROUGH SOUTHERN BAJA CALIFORNIA 
TO 22N130W THEN SOUTHWESTWARD TO A STRONG UPPER LEVEL LOW 
CENTERED W OF THE DISCUSSION AREA NEAR 13N144W. THIS DEEP 
LAYERED LOW WILL BEGIN TO WEAKEN...GRADUALLY BECOME ELONGATED BY 
SUNDAY...AND SHIFT SLOWLY EAST-NORTHEAST OVER THE UPCOMING 
WEEKEND. THE NORTHERN STREAM PATTERN WILL BECOME MORE AMPLIFIED 
OVER THE WEEKEND AS RIDGING BUILDS OVER THE SOUTHWESTERN U.S. 
BEHIND THE TROUGH...SLOWING DOWN AND INTENSIFYING THE PREVIOUSLY 
MENTIONED TROUGH ENTERING THE FORECAST AREA THIS EVENING FROM 
THE NW. 

AT THE LOWER LEVELS...A 1021 MB SUBTROPICAL HIGH CONTINUES TO 
INFLUENCE THE NORTHERN PORTION OF THE DISCUSSION AREA CENTERED 
NEAR 27N130W THAT EXTENDS A RIDGE AXIS TO 15N110W. N OF THE 
RIDGE AXIS...NORTHWESTERLY WINDS REMAIN IN THE 10 TO 15 KT RANGE 
HOWEVER ARE FORECAST TO GRADUALLY INCREASE OVERNIGHT INTO 
SATURDAY OVER THE AREA N OF 25N E OF 117W. SOUTH OF THE RIDGE 
AXIS...FRESH TO STRONG NE TRADEWINDS PREVAIL FROM 05N TO 18N W 
OF 128W WITH CONFUSED SEAS OF 10 TO 11 FT IN A BROAD MIX OF 
NE... SW...AND NW SWELL. THIS AREA OF FRESH TRADEWINDS IS 
FORECAST TO EXPAND NORTHWARD THROUGH SATURDAY AND EVENTUALLY 
MERGE INTO A LARGER SWATH OF NE WINDS IN ASSOCIATION WITH THE 
DISSIPATING COLD FRONT AND NE TRADES SOUTH OF HIGH PRESSURE 
BUILDING WESTWARD FROM THE CENTRAL PACIFIC.

LIGHT TO MODERATE WINDS OTHERWISE PREVAIL E OF 110W...WITH GAP 
WIND FLOW EXPECTED TO PULSE TO NEAR 20 KT DURING THE OVERNIGHT 
HOURS IN THE GULF OF PAPAGAYO TONIGHT BEFORE DIMINISHING.

$$
HUFFMAN