000
AXPZ20 KNHC 160341
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON MAY 16 2011

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM 
05N113W TO 05N125W TO 00N136W. SCATTERED MODERATE TO STRONG 
CONVECTION WAS WITHIN 180 NM S OF THE AXIS E OF 119W. SCATTERED 
MODERATE AND ISOLATED STRONG CONVECTION WAS WITHIN 90 NM EITHER 
SIDE OF THE AXIS BETWEEN 122W AND 130W.

...DISCUSSION...

AN UPPER LEVEL TROUGH DOMINATES THE NORTHERN WATERS EXTENDING 
FROM A DEEP LAYERED CYCLONE NEAR 42N125W JUST W OF EUREKA 
CALIFORNIA S INTO THE DISCUSSION WATERS NEAR 32N126W TO A BASE 
OVER THE TROPICS NEAR 15N140W. A WEAK ATTENDANT SURFACE COLD 
FRONT HAS OUTRUN THE UPPER TROUGH EXTENDING FROM THE NORTHERN 
BAJA CALIFORNIA PENINSULA TO NEAR 28N124W. NORTHERLY WINDS 
BEHIND THE FRONT HAVE RECENTLY DIMINISHED TO LESS THAN 20 KT 
ALTHOUGH LINGERING NORTHERLY SWELL TO 10 FT ALONG 30N PERSISTS 
BEHIND THE FRONT. THIS SWELL WILL GRADUALLY DECAY TO LESS THAN 8 
FT BY TUE MORNING.

UPPER RIDGING DOMINATES THE MAJORITY OF THE REMAINDER OF THE 
DISCUSSION WATERS. ONE RIDGE AXIS EXTENDS FROM THE U.S. ROCKY 
MOUNTAIN REGION DUE S ACROSS CENTRAL MEXICO CURVING MORE SE TO A 
PARENT UPPER ANTICYCLONE CENTERED OVER THE DEEP TROPICS NEAR 
05N96W. ADDITIONAL UPPER RIDGING EXTENDS ALONG THE SPINE OF 
CENTRAL AMERICA. CONVECTION IS VERY ACTIVE ALONG THE ITCZ AND S 
OF A CONNECTING TROUGH AXIS S OF THE AFOREMENTIONED DOMINANT 
RIDGE AXIS...WITH MODERATE SOUTHERLY FLOW CONVERGING WITH 
LIGHTER NORTHERLY FLOW OFF CENTRAL AMERICA. OTHER THAN THE ITCZ 
CONVECTION DESCRIBED ABOVE...THE CONNECTING TROUGH EXTENDED FROM 
08N100W TO 05N111W WITH SCATTERED MODERATE TO STRONG CONVECTION 
WITHIN 180 NM S OF THE TROUGH E OF 105W...AND SCATTERED MODERATE 
AND ISOLATED STRONG CONVECTION WITHIN 120 NM N OF THE TROUGH E OF
108W. ADDITIONAL CONVECTION...SCATTERED MODERATE AND ISOLATED 
STRONG...WAS NOTED WITHIN 120 NM EITHER SIDE OF A LINE FROM 
07N84W TO 04N93W.

AN AREA OF S TO SW 20 KT WINDS EXISTS S OF THE TROUGH AXIS S OF 
05N BETWEEN 87W AND 100W...ALTHOUGH WINDS SHOULD DIMINISH TO 
LESS THAN 20 KT EARLY MON AS THE TROUGHING WEAKENS.

ELSEWHERE AT THE SURFACE...1029 MB HIGH PRES IS CENTERED JUST NW 
OF THE WATERS WITH RIDGING EXTENDING FROM THE HIGH SE THROUGH 
30N140W TO NEAR 10N112W. A TIGHT PRES GRADIENT IS IN PLACE W OF 
THE BAJA CALIFORNIA PENINSULA BETWEEN THIS RIDGING AND THE ABOVE 
MENTIONED WEAKENING COLD FRONT. THIS PATTERN IS SUPPORTING 20 KT 
NORTHERLY WINDS WITHIN 120 TO 150 NM W OF THE PENINSULA. THESE 
WINDS WILL EXPAND IN COVERAGE AND INCREASE TO 20 TO 25 KT BY 48 
HOURS AS THE RIDGING TIGHTENS ONCE THE FRONT DISSIPATES AND AS A 
NEW COLD FRONT APPROACHES THE SOUTHERN CALIFORNIA COAST.

HIGH ENERGY CROSS EQUATORIAL SOUTHERLY SWELL WITH PEAK WAVE 
PERIODS OF 20 TO 22 SECONDS WILL CROSS THE EQUATOR INTO THE SW 
PORTION OF THE AREA LATER TONIGHT. THIS SWELL WILL ENCOMPASS 
APPROXIMATELY THE SW THIRD OF THE WATERS IN 24 HOURS THEN WILL 
CONTINUE PROPAGATING NE OVERTAKING THE SW TWO THIRDS OF THE AREA 
BY 48 HOURS AS SEAS BUILD TO BETWEEN 8 AND 11 FT. BEYOND 48 
HOURS...THE SWELL WILL ARRIVE AT THE COASTLINES OF MEXICO AND 
CENTRAL AMERICA EARLY TUE...THEN REACHING THE W COAST OF THE 
BAJA CALIFORNIA PENINSULA TUE EVENING. VERY LARGE AND DANGEROUS 
SURF WILL BE SEEN ALONG THE COASTS AND SHOALS OF THE REGION AS 
THE SWELL ARRIVES WITH OFFSHORE WAVE HEIGHTS FORECAST TO BUILD 
TO 8 TO 9 FT BY WED AFTERNOON BY BOTH THE WAVEWATCH AND EUROPEAN 
WAVE MODELS.

$$
LEWITSKY