000
AXPZ20 KNHC 160935
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAR 16 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

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

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED SOUTH OF 
THE EQUATOR. SCATTERED MODERATE CONVECTION FROM 02N TO 04N 
BETWEEN 89W AND 92W. 

...DISCUSSION...

A SHEARED UPPER LEVEL TROUGH STRETCHED NE TO SW ACROSS THE 
FORECAST AREA GENERALLY FROM NORTHERN BAJA CALIFORNIA THROUGH 
23N130W TO 10N146W. THIS TROUGH WILL BEGIN TO PHASE WITH AN 
AMPLIFYING NORTHERN STREAM TROUGH BEGINNING LATER TONIGHT. 
CURRENTLY...A SURFACE TROUGH ASSOCIATED WITH THE WEAK TROUGH 
ALOFT LIES OVER NW WATERS FROM 30N127W TO 26N137W. THIS 
TROUGH SEPARATES THE 1024 MB HIGH NEAR 27N126W OFF THE COAST OF 
BAJA CALIFORNIA NORTE FROM A 1030 MB SUBTROPICAL HIGH N OF 
HAWAII NEAR 31N157W. THE ZONALLY ORIENTED SUBTROPICAL RIDGE OVER 
N WATERS IS SUPPORTING A WIDE SWATH OF FRESH TRADE WINDS FROM 
07N TO 17N W OF 125W ACCORDING TO ASCAT AND OSCAT PASSES BETWEEN 
0514 AND 0740 UTC. AS THE AMPLIFYING NORTHERN STREAM TROUGH 
APPROACHES...THE HIGH PRES SYSTEM OFF THE BAJA WILL SHIFT 
WESTWARD AND MERGE WITH THE LARGER SUBTROPICAL HIGH. THE TRADE 
WINDS WILL SHIFT W OF 130W BY THE END OF THE FORECAST PERIOD SAT 
EVENING AS A RESULT. 

THE PRES GRADIENT BETWEEN THE HIGH OFF BAJA CALIFORNIA AND 
TROUGHING OVER NW MEXICO HAS ALLOWED FRESH NW WINDS TO SET UP 
ALONG THE W COAST OF BAJA CALIFORNIA ACCORDING TO A 0516 UTC 
ASCAT PASS AND THE 0734 UTC OSCAT PASS. THESE WINDS WILL 
DIMINISH SAT MORNING AS THE AFOREMENTIONED DEEP LAYER TROUGH AND 
ITS ASSOCIATED COLD FRONT APPROACHES...SLACKENING THE PRES 
GRADIENT. 

THE COLD FRONT WILL MOVE INTO NORTHERN FORECAST WATERS BY SAT 
MORNING. FRESH TO STRONG NW TO N WINDS OF 20 TO 30 KT...POSSIBLY 
NEAR GALE FORCE ALONG 30N WILL BE USHERED IN BY THE FRONT. NW 
SWELL WILL PROPAGATE AHEAD OF THE SYSTEM AND INCREASE SEAS TO 
8 TO 12 FEET BY SAT MORNING...AND REACH AS HIGH AS 15 TO 20 FEET 
BY SAT NIGHT N OF 28N BETWEEN 120W AND 132W. 

THE SOUTHERN STREAM UPPER JET ALONG 12N W OF 130W SPLITS AS IT 
MOVES EASTWARD...WITH THE SOUTHERN BRANCH CONTINUING ALONG 10N 
AND THE NORTHERN BRANCH DIRECTED INTO NW MEXICO...TRACKING ONTO 
THE LEADING EDGE OF THE AFOREMENTIONED WEAK UPPER TROUGH TO THE 
N. THE NORTHERN BRANCH OF THE JET IS TRANSPORTING TROPICAL 
MOISTURE IN THE MID AND UPPER LEVELS THROUGH THE SOUTHERN GULF 
OF CALIFORNIA INTO THE RIO GRANDE VALLEY. THIS MOISTURE IS 
MANIFESTED AS A BAND OF MULTI-LAYERED CLOUDS ALONG THE JET AXIS. 
THESE CONDITIONS WILL CONTINUE OVER THE NEXT TWO DAYS AS THE 
ORIENTATION OF THE NORTHERN BRANCH OF THE JET IS NOT EXPECTED TO 
CHANGE SIGNIFICANTLY.

GAP WINDS... 
GULF OF TEHUANTEPEC...THE SURFACE RIDGING AND ASSOCIATED PRES 
GRADIENT OVER SOUTHERN MEXICO AND THE ISTHMUS OF TEHUANTEPEC 
WILL GRADUALLY WEAKEN BEGINNING LATER TODAY. FRESH TO STRONG N 
TO NE WINDS IN THE GULF OF TEHUANTEPEC REGION ARE EXPECTED TO 
DIMINISH TO LESS THAN 20 KT BY SAT AFTERNOON.

GULF OF PAPAGAYO...FRESH TO STRONG TRADES ACROSS THE CARIBBEAN 
SEA CONTINUE TO FUNNEL NORTHEASTERLY GAP WINDS INTO THE GULF OF 
PAPAGAYO EXTENDING WESTWARD TO 97W. THE EDGE OF A 0330 UTC ASCAT 
PASS AND A FULL 0550 UTC OSCAT PASS CAPTURED THESE WINDS. AREA 
OF WINDS IS EXPECTED TO GRADUALLY SHRINK EASTWARD THROUGH SAT. 

GULF OF PANAMA...TRADES IN THE SW CARIBBEAN SEA WILL CONTINUE TO 
SUPPORT PULSES OF FRESH NORTHERLY FLOW ACROSS THE ISTHMUS OF 
PANAMA INTO THE GULF OF PANAMA. SEAS ARE EXPECTED TO REMAIN LESS 
THAN 8 FT WITH LITTLE CHANGE EXPECTED OVER THE NEXT 48 HOURS.

$$
COBB