000
AXPZ20 KNHC 020910
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON APR 02 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0645 UTC.

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

THE ITCZ AXIS EXTENDS FROM 09N121W TO 04N140W. SCATTERED 
MODERATE CONVECTION LIES WITHIN 75 NM EITHER SIDE OF THE AXIS 
BETWEEN 129W AND 133W.

...DISCUSSION...

THE AMPLIFIED NORTHERN STREAM PATTERN ALOFT CURRENTLY IN PLACE 
WILL GRADUALLY BREAK DOWN OVER THE NEXT TWO DAYS. THE UPPER 
TROUGH OVER THE INTERMOUNTAIN WESTERN U.S. AND NW MEXICO WILL 
PINCH A LOW OFF OVER THE FOUR CORNERS STATES TODAY. THIS LOW 
WILL SLOWLY MOVE EASTWARD TUE...ALLOWING THE RIDGING TO ITS W TO 
ERODE AS THE NEXT TROUGH APPROACHES. THIS SECOND TROUGH IS 
CONSIDERABLY LESS AMPLIFIED THAN THE TROUGH TO ITS E. THESE 
CHANGES TO THE PATTERN WILL ALLOW FOR THE FLOW TO BECOME 
RELATIVELY ZONAL ALOFT N OF 29N BY TUE. 

A 1032 MB SUBTROPICAL HIGH LIES NEAR 33N130W...AND THE COLD 
FRONT ASSOCIATED WITH THE EASTERN DEEP LAYER TROUGH IS BEGINNING 
TO DISSIPATE ACROSS THE CENTRAL GULF OF CALIFORNIA AND IN THE 
WATERS OFF BAJA CALIFORNIA SUR. THE 0424 UTC ASCAT PASS STILL 
SHOWS A LARGE AREA OF STRONG NW TO N WINDS JUST W OF BAJA 
CALIFORNIA...WITH A FEW BARBS TO 30 KT OFFSHORE OF BAHIA 
TORTUGAS MEXICO. THESE WINDS WILL DIMINISH TODAY AS THE 
SUBTROPICAL HIGH IS WEAKENED BY THE NEXT DEEP LAYER TROUGH 
APPROACHING FROM THE NW. THE COLD FRONT ASSOCIATED WITH THIS 
WESTERN TROUGH ALOFT WILL SLOWLY TO MOVE THROUGH NW WATERS 
BEGINNING TUE AFTERNOON. THIS FRONT WILL ENTER THE FORECAST AREA 
WITH CONSIDERABLY LESS FANFARE THAN ITS PREDECESSOR...WITH FRESH 
NE WINDS BEHIND IT AND SEAS TO 9 FT. MEANWHILE...NW SWELL BEHIND 
THE EASTERN COLD FRONT CONTINUES TO MOVE SOUTHWARD THROUGH THE 
FORECAST AREA. A JASON2 PASS MEASURED SEAS TO 18 FT OVER N 
CENTRAL WATERS AT 0350 UTC. 

FARTHER S...A NEARLY ZONAL SOUTHERN STREAM UPPER JET LIES OVER 
MUCH OF THE AREA S OF 20N W OF 110W. AN UPPER LOW NEAR 18N134W 
BREAKS UP THE JET...WITH W-SW FLOW ON ITS SE SIDE DIRECTING A 
STREAM OF TROPICAL MOISTURE ALOFT NORTHEASTWARD INTO THE 
FORECAST AREA W OF 120W. A BAND OF MULTI-LAYERED CLOUDINESS CAN 
BE FOUND WITHIN ABOUT 240 NM EITHER SIDE OF A LINE FROM 13N120W 
TO 06N140W AS A RESULT. DEEP CONVECTION IN THIS AREA IS 
PRIMARILY FOUND NEAR THE ITCZ. THIS CONVECTION IS DESCRIBED IN 
THE PREVIOUS SECTION. THE UPPER LOW WILL WEAKEN AS IT MOVES 
EASTWARD TO 120W THROUGH EARLY WED.

A SURFACE TROUGH LIES FROM 10N85W TO 05N90W TO 03N103W. 
SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 330 NM SE OF 
THE TROUGH BETWEEN 87W AND 91W. PRECIPITABLE WATER IMAGERY SHOWS 
THE POOL OF HIGHEST LOW TO MID LEVEL MOISTURE IN THE FORECAST 
AREA COINCIDES WITH THIS TROUGH. THIS AREA ALSO LIES UNDER A 
SPLIT IN THE ZONAL UPPER JET AROUND 120W...WITH THE SOUTHERN 
PORTION OF THE JET DIRECTING NW WINDS OVER THE WESTERN PORTION 
OF THE TROUGH WHILE SW WINDS LIE OVER THE EASTERN PORTION OF THE 
FRONT. THE CONVECTION LIES UNDER THE AREA OF GREATEST UPPER 
LEVEL DIFFLUENCE NEAR THE MIDDLE OF THE TROUGH. CONDITIONS 
SHOULD CONTINUE TO SUPPORT CONVECTION IN THIS REGION THROUGH 
EARLY WED.

GULF OF CALIFORNIA...A DISSIPATING COLD FRONT WILL SWEEP THROUGH 
THE CENTRAL GULF OF CALIFORNIA EARLY THIS MORNING BEFORE 
DISSIPATING OVER THE SOUTHERN GULF BY SUNSET. NW WINDS BEHIND 
THE FRONT APPEAR TO HAVE INCREASED TO 20 TO 25 KT IN RESPONSE TO 
THE SUBTROPICAL RIDGE BUILDING IN THE WAKE OF THE FRONT. WINDS 
WILL DIMINISH BY LATE MON INTO TUE MORNING AS THE FRONT 
DISSIPATES AND THE HIGH PRES N OF THE AREA WEAKENS.

$$
SCHAUER