000
AXPZ20 KNHC 032109
TWDEP 

TROPICAL WEATHER DISCUSSION                                   
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC WED APR 03 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2000 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 08N78W TO 09N86W TO 
04N100W. THE ITCZ AXIS WAS ANALYZED FROM 04N100W TO 04N120W. 
SCATTERED MODERATE CONVECTION WAS WITHIN 60 NM N AND 270 NM S OF 
THE AXIS BETWEEN 82W AND 90W.

...DISCUSSION...                                               
THE UPPER PATTERN CURRENTLY FEATURES A LONG-WAVE TROUGH ALONG 
104W WITH WEAK RIDGING TO ITS E AND A MORE AMPLIFIED RIDGE TO 
ITS W. AN UPPER LOW LIES NW OF THE FORECAST AREA NEAR 40N142W. 
AN UPPER JET ON THE SE SIDE OF THE LOW MEETS UP WITH THE 
SOUTHERN STREAM UPPER JET OVER WATERS W OF 125W AND N OF 10N. 
THIS MERGED JET IS TRANSPORTING TROPICAL MOISTURE INTO THE 
FORECAST AREA. MULTI-LEVELED CLOUDS AND SCATTERED SHOWERS LIE 
WITHIN 270 NM EITHER SIDE OF A LINE FROM 32N129W TO 00N125W. THE 
PATTERN IS PROGRESSIVE. THE UPPER LOW IS DRAGGING A NEGATIVELY 
TILTED TROUGH THROUGH NORTHERN WATERS THAT WILL WEAKEN AND RACE 
EASTWARD INTO THE WESTERN U.S. ON FRI. MEANWHILE...THE LONG-WAVE 
TROUGH WILL MOVE EASTWARD ACROSS MEXICO AND STRETCH FROM THE 
GULF OF TEHUANTEPEC TO 02N104W BY FRI AFTERNOON.

THE WEAKENED 1022 MB SUBTROPICAL SURFACE HIGH LIES NEAR 29N125W. 
A COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED UPPER LOW WAS 
ANALYZED FROM 32N134W TO 30N134W TO 23N140W. THIS WEAK COLD 
FRONT WILL EDGE SLIGHTLY FARTHER EASTWARD AS IT DISSIPATES 
OVERNIGHT. THE SUBTROPICAL HIGH WILL MERGE WITH HIGH PRES BEHIND 
THE COLD FRONT...REORIENTING THE RIDGE AXIS SOUTHWARD ALONG 25N 
W OF 125W THU. THE CONSOLIDATED HIGH WILL STRENGTHENING OVER NW 
WATERS ON FRI. TRADE WINDS WILL REMAIN A MODERATE TO FRESH 
BREEZE AT MOST THROUGH LATE FRI AS A RESULT OF THE WEAK 
SUBTROPICAL HIGH.
 
A COLD FRONT PASSING THROUGH THE SW GULF OF MEXICO LATE THU WILL 
MOVE THROUGH CHIVELA PASS AND BRING STRONG N WINDS INTO THE GULF 
OF TEHUANTEPEC OVERNIGHT THU NIGHT. WINDS ARE EXPECTED TO REACH 
NEAR GALE FORCE ON FRI WITH SEAS BUILDING TO 12 FT. 

NW SWELL WITH PERIODS EXCEEDING 20 SECONDS WILL MOVE INTO NW 
WATERS ON FRI. SEAS THERE ARE EXPECTED TO BUILD TO 9 FT BY FRI 
AFTERNOON.

$$
SCHAUER