000
AXPZ20 KNHC 310905
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED MAR 30 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 0745 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM 08N81W 
TO 03N95W TO 05N117W TO 01N140W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION WAS WITHIN 75 NM EITHER SIDE OF THE 
ITCZ AXIS E OF 84W TO WESTERN PANAMA. ISOLATED MODERATE 
CONVECTION WAS WITHIN 210 NM S OF THE ITCZ AXIS BETWEEN 114W AND 
120W.

...DISCUSSION...

A 1034 MB SUBTROPICAL HIGH PRES SYSTEM NEAR 36N135W EXTENDS A 
RIDGE INTO THE FORECAST AREA NEAR 32N133W THROUGH 19N122W TO 
14N100W. FRESH NE TRADE WINDS LIE S OF THE RIDGE AXIS FROM 06N 
TO 28N W OF 130W ACCORDING TO THE 0614 UTC ASCAT PASS. THESE 
TRADES ARE FORECAST TO DISSIPATE OVER THE NEXT 24 HOUR AS THE 
HIGH PRES SYSTEM WEAKENS AND MIGRATES TO THE W.

THE PRES GRADIENT BETWEEN THE SUBTROPICAL RIDGE AND LOWER PRES 
OVER NE WATERS CONTINUES TO BE STRONG ENOUGH TO SUPPORT FRESH N 
TO NE WINDS N OF 26N BETWEEN 122W AND 130W. THIS AREA OF WIND IS 
EXPECTED TO SHIFT W TODAY AS THE SUBTROPICAL HIGH SHIFTS W AND 
PUSHES THE TIGHTEST PRES GRADIENT W WITH IT. THE SUBTROPICAL 
HIGH WILL WEAKEN ENOUGH OVERNIGHT TONIGHT FOR THESE WINDS TO 
DIMINISH BELOW ADVISORY CRITERIA.

AN UPPER TROUGH LIES FROM THE SOUTHERN TIP OF BAJA CALIFORNIA 
NORTHWESTWARD THROUGH THE AREA TO 33N138W THEN SOUTHWESTWARD TO 
AN UPPER LOW NEAR 27N141W. AN UPPER RIDGE AXIS TO ITS S LIES 
FROM 27N129W TO 16N125W AND WILL AMPLIFY TODAY...BREAKING THE 
TROUGHING OVER NORTH AMERICA AWAY FROM THE UPPER LOW JUST W OF 
THE FORECAST AREA. A 40-60 KT SOUTHWESTERLY UPPER JET LIES ON 
THE SE SIDE OF THE UPPER LOW W OF THE RIDGE AXIS. THIS JET IS 
TRANSPORTING SUBTROPICAL MOISTURE NORTHEASTWARD INTO THE REGION 
W OF THE RIDGE AND N OF 15N. THIS AREA IS MARKED BY MULTI-LEVEL 
CLOUDINESS...WITH A BLANKET OF STRATOCUMULUS STRETCHING OUTSIDE 
THIS REGION TO ENCOMPASS MUCH OF THE AREA N OF 15N W OF 115W.

A DISSIPATING ANTICYCLONE ALOFT LIES OVER WESTERN NICARAGUA 
EXTENDS A RIDGE AXIS SOUTHWESTWARD TO 00N98W AND EXTENDS ANOTHER 
RIDGE AXIS THROUGH PANAMA INTO COLOMBIA. THE STRONGEST 
CONVECTION ALONG THE ITCZ LIES E OF 85W NEAR THE COAST OF PANAMA 
AND COINCIDES WITH DIFFLUENCE ASSOCIATED WITH THE RIDGE AXIS 
ALOFT. THIS CONVECTION IS DESCRIBED IN THE ITCZ SECTION ABOVE.

FARTHER W...CONVECTION ALONG THE ITCZ IS FOCUSED JUST TO THE SW 
OF A SURFACE TROUGH ANALYZED ALONG 121W FROM 04N TO 10N. THIS 
TROUGH IS A REFLECTION OF AN UPPER TROUGH THAT STRETCHES FROM 
CABO CORRIENTES MEXICO TO THE EQUATOR NEAR 116W. THE CONVECTION 
HERE IS BEING ENHANCED BY UPPER DIFFLUENCE BETWEEN THIS TROUGH 
AND A RIDGE AXIS FROM 07N127W TO 00N136W. INCREASING 
NORTHWESTERLY WINDS ALOFT ARE CARRYING THE CONVECTIVE BLOW OFF S 
OF THE ITCZ. 

$$
SCHAUER