000
AXPZ20 KNHC 141512
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC SAT MAR 14 2015

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1230 UTC. 
 
...SPECIAL FEATURES...

GULF OF TEHUANTEPEC GALE WARNING...1019 MB HIGH PRESSURE 
CENTERED OVER THE NORTHWESTERN GULF OF MEXICO NEAR 26N94W IS 
SUPPORTING A SMALL AREA OF STRONG TO NEAR GALE FORCE WINDS 
FUNNELING THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC 
ACCORDING TO THE 0910 UTC RAPIDSCAT PASS. DRAINAGE FLOW OFF THE 
LAND EARLY THIS MORNING SHOULD HAVE ENHANCED THE WIND ENOUGH TO 
REMAIN AS HIGH AS 30 KT THROUGH 1200 UTC THIS MORNING. THE HIGH 
PRESSURE OVER THE GULF WILL WEAKEN THROUGH TONIGHT...WITH WINDS 
EXPECTED TO DROP BELOW THE ADVISORY CRITERIA OF 20-25 KT BY THIS 
EVENING. WINDS AGAIN REACH ADVISORY CRITERIA OVERNIGHT TONIGHT. 
MEANWHILE...HIGH PRESSURE OVER THE U.S. HIGH PLAINS WILL MOVE 
INTO THE MID MISSISSIPPI VALLEY AND EXTENDS A RIDGE AXIS SW INTO 
NORTHEASTERN MEXICO BY SUN NIGHT JUST AS A N TO S TROUGH BUILDS 
OVER THE WESTERN GULF. THIS SET UP WILL ALLOW N WINDS TO FUNNEL 
THROUGH CHIVELA PASS. WINDS WILL INCREASE TO GALE FORCE IN THE 
GULF OF TEHUANTEPEC BY SUN EVENING AND REMAIN AT MINIMAL GALE 
STRENGTH THROUGH THE END OF THE FORECAST PERIOD MON MORNING. 
SEAS WILL HOVER IN THE 7-9 FT RANGE TODAY THROUGH SUN AND BUILD 
AS HIGH AS 12 FT UNDER THE GALE CONDITIONS BY MON MORNING.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
            
THE MONSOON TROUGH WAS ANALYZED FROM 10N85W TO 05N90W TO 04N103W 
TO 05N109W. THE ITCZ AXIS WAS ANALYZED FROM 05N109W TO 08N115W 
TO 04N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 240 NM N 
AND 60 NM S OF THE AXIS BETWEEN 96W AND 104W. A TROUGH WAS 
ANALYZED FROM 13N111W TO 08N115W. SCATTERED MODERATE CONVECTION 
WAS WITHIN 240 NM E OF TROUGH.

...DISCUSSION... 

AN ACCELERATING DEEP LAYER TROUGH IS MOVING INTO NW WATERS. A SW 
JET ON THE LEADING EDGE OF THE WESTERN TROUGH IS PROPELLING 
MOISTURE ALOFT INTO THE FORECAST AREA. SATELLITE IMAGERY SHOWS A 
VAST AREA OF MULTI-LAYERED CLOUDS WITH SOME EMBEDDED SHOWERS W 
OF A LINE FROM 32N129W TO 10N140W. A COLD FRONT AT THE SURFACE 
STRETCHES FROM 32N139W TO 23N140W. THE DEEP LAYERED TROUGH 
SHOULD WEAKEN THROUGH THE END OF THE FORECAST PERIOD MON 
MORNING...ALLOWING THE COLD FRONT TO DISSIPATE. THE 1220 UTC 
RAPIDSCAT PASS SHOWED SOUTHERLY WINDS OVER ADVISORY CRITERIA 
AHEAD OF THE FRONT IN NW WATERS. WINDS TO ADVISORY CONDITIONS 
SHOULD LINGER NEAR THE FRONT UNTIL SUN MORNING OVER FAR N 
WATERS. NW SWELL IN THE 8 TO 10 FT RANGE WILL IMPACT MUCH OF THE 
AREA W OF 132W THROUGH MON MORNING. 

THE 1020 MB HIGH PRESSURE CENTER NEAR 33N127W EXTENDS A RIDGE 
AXIS AHEAD OF THE AFOREMENTIONED COLD FRONT TO 20N140W. THIS 
WEAK RIDGE IS ONLY SUPPORTING GENTLE TRADE WINDS BETWEEN IT AND 
THE ITCZ TO ITS S. THE RIDGE WILL DISSIPATE THROUGH SUN AS THE 
COLD FRONT ADVANCES EASTWARD...WITH THE HIGH PRESSURE BEHIND THE 
COLD FRONT BECOMING DOMINANT BY SUN NIGHT. THIS NEW RIDGE WILL 
ALSO BE WEAK...SUPPORTING ONLY MODERATE TRADES. 

A PERSISTENT UPPER TROUGH LIES OVER MEXICO ALONG 105W. THIS 
TROUGH IS EXPECTED TO CUT OFF FROM THE NORTHERN STREAM 
SUN...LEAVING AN UPPER LOW OVER THE SOUTHERN GULF OF CALIFORNIA. 
PACIFIC MOISTURE IS FEEDING INTO THE LEADING EDGE OF THIS TROUGH 
WHERE POSITIVE VERTICAL MOTION IS ENHANCING CONVECTION OVER 
CENTRAL MEXICO AS WELL AS NEAR THE PRIMARILY SHORTWAVE SYSTEM 
NEAR MAZATLAN. THIS UPPER TROUGH AND LOW WILL REFLECT TO THE 
SURFACE BY SUN. AN AREA OF FRESH TO STRONG E-NE WINDS WITH SEAS 
TO 9 FT IS EXPECTED TO PERSIST ALONG THE CENTRAL MEXICAN COAST 
IN THE VICINITY OF MANZANILLO SUN AFTERNOON THROUGH AT LEAST 
MON MORNING. 

GAP WINDS...                                                     
GULF OF PAPAGAYO...HIGH PRES EXTENDING FROM THE WESTERN ATLC 
THROUGH THE NW CARIBBEAN INTO CENTRAL AMERICA WILL WEAKEN TODAY 
ONLY TO BE REPLACED BY A BUILDING HIGH PRESSURE CENTERED OVER 
THE LOWER MISSISSIPPI VALLEY SUN. A MODERATE PRESSURE GRADIENT 
BETWEEN THIS RIDGING TO THE N AND THE MONSOON TROUGH TO THE S 
SHOULD ALLOW FRESH TO STRONG E-NE WINDS IN THE LATE NIGHT AND 
EARLY MORNING HOURS FROM THE GULF OF PAPAGAYO AREA DOWNWIND TO 
AROUND 90W TO CONTINUE THROUGH AT LEAST MON MORNING. 

$$
SCHAUER