000
AXPZ20 KNHC 202125
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU MAY 20 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 84W N OF 02N IS MOVING W AT 10 KT. CLUSTERS 
OF MODERATE TO STRONG CONVECTION WERE NOTED N OF 05N BETWEEN 83W 
AND 90W. DUE TO THE TROUGHING DOWNSTREAM OF THIS WAVE...VERY 
SLOW W TO NW MOTION IS EXPECTED DURING THE NEXT 24 HOURS. 

TROPICAL WAVE ANALYZED FROM 05N108W TO 10N103.5W WITH A WEAK LOW 
TO MID LEVEL CYCLONIC CIRCULATION INDICATED IN SATELLITE IMAGERY 
NEAR 08N106W. CONVECTION NEAR THE WAVE REMAINS MODEST. 

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED ALONG 
08.5N83W TO 09.5N92W TO 08N100W TO 06N118W TO 08N129W TO 
06N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WITHIN 
90 NM N OF AXIS W OF 134W.

...DISCUSSION...
AT THE SURFACE...HIGH PRES 1032 MB CENTERED NEAR 35N145W...AND 
RESULTING PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE AND LOWER 
PRESSURE OF THE ITCZ ARE RESULTING IN FRESH TO STRONG TRADES 
FROM 07N TO 20N W OF 126W. THERE IS ALSO A TIGHT PRESSURE 
GRADIENT IN PLACE BETWEEN THE HIGH PRESSURE TROUGHING FROM THE 
SOUTHERN PLAINS THROUGH CENTRAL MEXICO RESULTING IN NW TO N 
WINDS ALONG THE W COAST OF BAJA CALIFORNIA IN THE 20-25 KT 
RANGE. THE STRONG PRES GRADIENT OVER NE WATERS WILL BE 
MAINTAINED THROUGH THE FORECAST PERIOD. LOOK FOR NE TRADE WINDS 
TO EXPAND N BEYOND 25N OVER THE NEXT FEW DAYS AS A RESULT OF THE 
TIGHTENED PRES GRADIENT BETWEEN THE BUILDING SUBTROPICAL HIGH 
AND THE ITCZ TO THE S.

AN UPPER LEVEL ANTICYCLONE WAS CENTERED NEAR 14N93W AND 
GRADUALLY SHIFTING W...WITH A RIDGE AXIS EXTENDING W TO 120W. 
MEANWHILE...A 50-70 KT W-SW UPPER JET PARALLELS THE RIDGE AXIS 
WITH ITS JET CORE APPROXIMATELY 510 NM N OF THIS RIDGE. THE JET 
IS TRANSPORTING CONVECTIVE DEBRIS FROM THE ITCZ NORTHEASTWARD 
INTO SOUTHERN MEXICO.

CROSS-EQUATORIAL LONG PERIOD SW SWELL HAS REACHED MUCH OF THE 
PACIFIC COASTLINE WITHIN THE FORECAST AREA WITH WAVE HEIGHTS IN 
THE 4-7 FT RANGE...WITH THE EXCEPTION OF THE W COAST OF BAJA 
CALIFORNIA WHERE NW WIND WAVES HAVE DRIVEN SEAS UP TO 6-9 FT. 
THIS WAVE TRAIN IS EXCEPTED TO REACH THE MEXICAN AND CENTRAL 
AMERICAN COAST BY FRI MORNING AND WILL INCREASE WAVES TO 10 FT 
IN 20 SECOND SWELL IN THE COASTAL WATERS FRI INTO THE 
WEEKEND...MAKING FOR DANGEROUS SURF CONDITIONS ESPECIALLY ON 
SOUTH FACING BEACHES. SEAS ARE EXPECTED TO RISE ABOVE 8 FEET 
OVER THE ENTIRE FORECAST AREA BY SAT MORNING AS THE SW SWELL 
SPREADS NORTH THROUGH THE REGION.

$$
AL/STRIPLING