000
AXPZ20 KNHC 170315
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 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 WILL BE ENTERING THE NW CORNER OF THE 
FORECAST AREA OVERNIGHT TONIGHT. THIS FRONT WILL SWEEP 
SOUTHEASTWARD ACROSS BAJA CALIFORNIA OVER THE NEXT FEW 
DAYS...WITH PEAK NW WINDS REACHING JUST BELOW GALE FORCE. 
WESTERLY WINDS WILL FUNNEL THROUGH MOUNTAIN PASSES IN BAJA 
CALIFORNIA NORTE ALLOWING FOR LOCALLY STRONGER WINDS IN THE 
NORTHERN GULF OF CALIFORNIA FROM SAT EVENING THROUGH THE END OF 
THE FORECAST PERIOD SUN EVENING. 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.

A ZONALLY ORIENTED SUBTROPICAL RIDGE ALONG 26N IS SUPPORTING A 
WIDE SWATH OF FRESH TRADE WINDS FROM 06N TO 19N W OF 125W 
ACCORDING TO THE 1746 UTC AND 1926 UTC ASCAT PASSES. THIS AREA 
OF TRADE WINDS WILL SHIFT SLIGHTLY FARTHER TO THE W BY SAT 
EVENING. 

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 08N84W TO 04N90W TO 04N100W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION CAN BE FOUND 
WITHIN 90 NM EITHER SIDE OF THE TROUGH BETWEEN 85W 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 TO STRONG N TO NE WINDS IN THE GULF 
OF TEHUANTEPEC WERE OBSERVED BY THE 1858 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 BY SAT AFTERNOON.

GULF OF PAPAGAYO...FRESH TO STRONG TRADES ACROSS THE CARIBBEAN 
SEA CONTINUE TO FUNNEL NORTHEASTERLY GAP WINDS OF 20 TO 25 KT 
INTO THE GULF OF PAPAGAYO EXTENDING WESTWARD TO 96W ACCORDING TO 
THE 1604 UTC ASCAT AND 1858 UTC OSCAT PASSES. PEAK WINDS WILL 
DECREASE AND THE AREA OF FRESH WINDS IS EXPECTED TO SHRINK 
EASTWARD THROUGH SUN. 

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 SAT AFTERNOON.

$$
SCHAUER