000
AXPZ20 KNHC 170911
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT MAR 17 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 
0915 UTC.

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

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED SOUTH OF 
THE EQUATOR. NO SIGNIFICANT DEEP CONVECTION.

...DISCUSSION...

A STRONG COLD FRONT HAS ENTERED THE FAR NW PORTION OF THE 
FORECAST AREA AND EXTENDS FROM 30N132W TO 29N138W. THE FRONT 
WILL SWEEP SOUTHEASTWARD ACROSS BAJA CALIFORNIA OVER THE NEXT 
FEW DAYS...WITH PEAK NW WINDS REACHING JUST BELOW GALE FORCE
ALONG 30N. WESTERLY WINDS WILL FUNNEL THROUGH MOUNTAIN PASSES IN 
BAJA CALIFORNIA NORTE ALLOWING FOR LOCALLY STRONGER WINDS IN THE 
NORTHERN GULF OF CALIFORNIA FROM THIS EVENING THROUGH THE END OF 
THE FORECAST PERIOD OVERNIGHT SUN. NORTHWEST SWELL ASSOCIATED 
WITH THIS FRONT HAS ALREADY INCREASED SEAS TO 11 FT OVER NW 
WATERS. SEAS BEHIND THE FRONT WILL REACH AS HIGH AS 20 FT OFF 
THE W COAST OF BAJA CALIFORNIA NORTE BY SUN AFTERNOON.

A ZONALLY ORIENTED SUBTROPICAL RIDGE ALONG 25N/26N IS SUPPORTING 
A WIDE SWATH OF FRESH TRADE WINDS FROM 06N TO 17N W OF 125W. 
THESE WINDS WERE CAPTURED BY A 0224 UTC WINDSAT AND A SUBSEQUENT 
0632 UTC ASCAT PASS. THIS AREA OF TRADE WINDS WILL SHIFT 
SLIGHTLY FARTHER TO THE W BY TONIGHT BUT THEN REBUILD EASTWARD
TO 120W AGAIN BY SUN NIGHT. 

A POSITIVELY TILTED UPPER LEVEL TROUGH IS STRETCHED NE TO SW 
ACROSS THE FORECAST AREA GENERALLY FROM NORTHERN BAJA CALIFORNIA 
TO 10N140W. THIS TROUGH IS BEGINNING TO PHASE WITH AN AMPLIFYING 
NORTHERN STREAM TROUGH IN ASSOCIATED WITH THE AFOREMENTIONED 
COLD FRONT. THE SOUTHERN STREAM UPPER JET IS FOUND ON THE 
LEADING EDGE OF THIS POSITIVELY TILTED TROUGH. 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. THIS BAND OF CLOUDS WILL GRADUALLY 
SHIFT SOUTHWARD THROUGH MEXICO AS THE POSITIVELY TILTED TROUGH 
IS PUSHED EASTWARD BY INTRUDING NORTHERN STREAM TROUGH.

A SURFACE TROUGH LIES FROM 08N83W TO 04N90W TO 04N100W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION CAN BE FOUND 
WITHIN 60-90 NM EITHER SIDE OF THE TROUGH BETWEEN 86W AND 94W. 
THIS CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE 
ASSOCIATED WITH THE REAR RIGHT QUADRANT OF THE SOUTHWESTERLY 
UPPER JET OVER THE CARIBBEAN SEA. 

GAP WINDS... 
GULF OF TEHUANTEPEC...FRESH 20 KT N TO NE WINDS IN THE GULF OF 
TEHUANTEPEC WERE CAPTURED BY A 0310 UTC ASCAT AND 0550 UTC OSCAT 
PASS. SURFACE RIDGING AND THE ASSOCIATED PRES GRADIENT OVER 
SOUTHERN MEXICO AND THE ISTHMUS OF TEHUANTEPEC WILL WEAKEN 
TONIGHT...AND THESE WINDS WILL DIMINISH TO LESS THAN 20 KT LATER 
THIS AFTERNOON.

GULF OF PAPAGAYO...FRESH TO STRONG TRADES ACROSS THE CARIBBEAN 
SEA CONTINUE TO FUNNEL NORTHEASTERLY GAP WINDS OF 20 KT INTO THE 
GULF OF PAPAGAYO EXTENDING WESTWARD TO 96W ACCORDING TO THE 0310 
UTC ASCAT AND 0546 UTC OSCAT PASSES. PEAK WINDS WILL DECREASE 
AND THE AREA OF FRESH WINDS IS EXPECTED TO SHRINK EASTWARD 
THROUGH SUN NIGHT. 

GULF OF PANAMA...TRADES IN THE SW CARIBBEAN SEA WILL CONTINUE TO 
SUPPORT FRESH NORTHERLY FLOW ACROSS THE ISTHMUS OF PANAMA INTO 
THE GULF OF PANAMA FOR NOW. WINDS IN THE GULF OF PANAMA ARE 
EXPECTED TO DROP CONSISTENTLY BELOW 20 KT BY THIS AFTERNOON.

$$
COBB