000
AXPZ20 KNHC 031504
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN JUN 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1300 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 11N109W TO LOW PRES NEAR 08N118W 
TO 06N125W. THE ITCZ EXTENDS FROM 06N125W TO BEYOND 06N140W. NO 
SIGNIFICANT CONVECTION IS NOTED.

...DISCUSSION...

THE AMPLIFIED UPPER PATTERN IN THE PACIFIC WILL BEGIN TO DAMPEN 
OVER THE NEXT FEW DAYS. THIS PATTERN IS CURRENTLY MARKED BY AN 
ANTICYCLONE CENTERED OVER EASTERN HONDURAS/NICARAGUA...AN UPPER 
TROUGH FROM THE TEXAS BIG BEND TO 10N107W...A RIDGE ALONG 120W N 
OF 10N...AND A CUT OFF LOW JUST E OF THE HAWAIIAN ISLANDS 
CENTERED NEAR 21N149W. UPPER DIFFLUENCE ON THE SOUTH SIDE OF THE 
ANTICYCLONE OVER CENTRAL AMERICA IS ENHANCING THE SCATTERED 
MODERATE WITH ISOLATED STRONG FROM 02N TO 10N E OF 87W INCLUDING 
THE GULF OF PANAMA. THE UPPER PATTERN WILL DAMPEN AS THE RIDGING 
OVER CENTRAL WATERS IS WEAKENED BY A PROGRESSIVE NORTHERN STREAM 
TROUGH ENCROACHING ON ITS NORTHERN SIDE ON ITS WAY INTO THE U.S. 
WEST COAST BY TUE MORNING. 

AT THE SURFACE...A WEAK RIDGE LIES ALONG 30N W OF 128W AND 
EXTENDS SOUTHEASTWARD TO 20N116W. FRESH NW TO N WINDS LIE E OF 
THE RIDGE AXIS OVER NE WATERS WHERE THE PRES GRADIENT IS 
TIGHTEST BETWEEN THE RIDGE AND TROUGHING OVER THE SOUTHWESTERN 
U.S. AND NORTHERN MEXICO. THESE WINDS WERE SAMPLED BY THE 0442 
UTC ASCAT PASS N OF 27N BETWEEN 120W AND 125W AND ARE EXPECTED 
TO DIMINISH TO A MODERATE TO GENTLE BREEZE TONIGHT AS A COLD 
FRONT PUSHES INTO NW WATERS...WEAKENING THE RIDGE. THIS COLD 
FRONT IS ASSOCIATED WITH THE AFOREMENTIONED TROUGH ALOFT THAT 
WILL TEMPER THE AMPLIFICATION OF THE UPPER PATTERN OVER THE 
NORTHERN PORTION OF THE FORECAST AREA. THE COLD FRONT WILL USHER 
FRESH N TO NE WINDS INTO NW WATERS BEGINNING EARLY MON MORNING. 
THE SUBTROPICAL HIGH CURRENTLY RESIDES WELL NW OF THIS FRONT 
NEAR 39N157W. THE HIGH WILL SHIFT SOUTHEASTWARD BEHIND THE COLD 
FRONT. THE BUILDING SUBTROPICAL RIDGE WILL INCREASE THE PRES 
GRADIENT N OF THE ITCZ OVER W WATERS AND ALLOW FRESH NE TRADE 
WINDS TO RETURN STARTING MON. 

CROSS-EQUATORIAL SW SWELL WITH PERIODS AROUND 15-17 SECONDS HAS 
MADE ITS WAY TO THE COAST OF CENTRAL AMERICA AND MEXICO SOUTH OF 
BAJA CALIFORNIA NORTE THIS MORNING. THIS SWELL IS MEETING UP 
WITH THE NORTHERLY SWELL FOUND OFF BAJA CALIFORNIA...ENLARGING 
THE AREA OF 8 FT SEAS. SEAS ASSOCIATED WITH THIS SWELL TRAIN ARE 
UNDER 8 FT IN THE REMAINDER OF THE REGION EXCEPT NEAR THE 1009 
MB LOW PRES SYSTEM EMBEDDED IN THE ITCZ. SEAS TO 8 FT STILL 
LINGER NEAR THIS LOW DESPITE THE WINDS AROUND THE LOW 
DIMINISHING BELOW 20 KT. THIS LOW IS FORECAST TO CONTINUE 
WESTWARD AROUND 10 KT OVER THE NEXT FEW DAYS. AS THE SUBTROPICAL 
RIDGE BUILDS TO ITS N...WINDS ARE EXPECTED TO PICK UP TO 20 KT 
IN ITS NW QUADRANT. 

$$
SCHAUER