000
AXPZ20 KNHC 072138
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC TUE APR 07 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY  
THROUGH 2000 UTC. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
          
THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED FROM 04N90W TO 
04N117W TO 03N125W TO 04N140W. ISOLATED MODERATE CONVECTION WAS 
S OF THE AXIS TO 00N BETWEEN 90W-100W. SCATTERED MODERATE 
CONVECTION WAS S OF THE AXIS BETWEEN 103W-110W AS WELL AS S OF 
AXIS BETWEEN 116W-126W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION WAS FROM 05N-10N W OF 130W. 

...DISCUSSION... 

THE SUBTROPICAL HIGH IS BEING COMPROMISED BY A COLD FRONT 
STRETCHING FROM NEAR PISMO BEACH CALIFORNIA THROUGH 32N124W TO 
30N130W. THE MAIN HIGH PRESSURE CENTER WAS ANALYZED NEAR 35N140W 
AT 1023 MB WITH A SECOND...PINCHED OFF...1021 MB HIGH S OF THE 
FRONT NEAR 27N129W. A WEAK RIDGE STRETCHES OVER THE FORECAST 
AREA FROM THE SECOND HIGH TO NEAR 13N98W. ASCAT DATA SHOWS TRADE 
WINDS OVER W WATERS ON THE SW SIDE OF THE RIDGE ARE A MODERATE 
TO FRESH BREEZE. ALTIMETER DATA SHOWS SEAS TO 8 FT LIE WITHIN 
THE AREA OF FRESH TRADES OVER WATERS W OF 133W. THIS AREA OF 
SEAS TO 8 FT WILL SHIFT W OF THE AREA THROUGH WED NIGHT. 

THE SECOND HIGH CENTER IS EXPECTED TO DISSIPATE OVER THE NEXT 24 
HOURS WHILE THE MAIN SUBTROPICAL HIGH IS FORCED EASTWARD JUST N 
OF THE AREA BY AN APPROACHING COLD FRONT WED AND THEN DIP INTO 
THE FORECAST AREA...LYING NEAR 28N123W BY THE END OF THE 
FORECAST PERIOD THU AFTERNOON. THE HIGH WILL REMAIN WEAK ENOUGH 
TO PREVENT TRADE WINDS FROM INCREASING TO THE ADVISORY CRITERIA 
OF A FRESH TO STRONG BREEZE...BUT MERGING NE...SW AND NW SWELL 
IN THE TRADE WIND ZONE WILL CONTINUE TO SUPPORT AN AREA OF SEAS 
TO 8 FT CENTERED WITHIN ABOUT 150 NM OF 10N120W THAT IS FORECAST 
TO MIGRATE NW TO NEAR 13N129W THROUGH THU MORNING. 

THE COLD FRONT ENCROACHING ON THE SUBTROPICAL HIGH IS FORECAST 
TO REACH THE NW FORECAST WATERS THU. WINDS ARE EXPECTED TO BE 
BELOW ADVISORY CRITERIA...AND NW SWELL WILL BE SLOW TO BUILD 
SEAS OVER 8 FT.

GAP WINDS...                                                     
GULF OF TEHUANTEPEC...A QUICK BURST OF N WINDS IS FORECAST IN 
THE GULF OF TEHUANTEPEC IN THE MORNING HOURS ON WED. THE 
PRESSURE GRADIENT BETWEEN A MERIDIONAL TROUGH OVER THE BAY OF 
CAMPECHE AND RIDGING TO ITS NW WILL FORCE N WINDS THROUGH 
CHIVELA PASS. THESE WINDS WILL BE ENHANCED BY NOCTURNAL DRAINAGE 
FLOW. WINDS ARE FORECAST TO REACH AS STRONG AS 30 KT WED MORNING 
BEFORE DIMINISHING MIDDAY. 

GULF OF PAPAGAYO...THE PRESSURE GRADIENT BETWEEN RIDGING OVER 
THE NW CARIBBEAN AND THE ITCZ TO THE SW IS SUPPORTING A FRESH TO 
STRONG NE BREEZE OBSERVED BY THE 1554 UTC ASCAT-A PASS. NOCTURNAL 
DRAINAGE FLOW WILL ENHANCE THESE WINDS TO NEAR GALE FORCE EARLY 
WED. THE PRESSURE GRADIENT WILL WEAKEN THROUGH THE REMAINDER OF 
THE FORECAST PERIOD...WITH WINDS EXPECTED TO DIP BELOW THE 
ADVISORY CRITERIA BY THE END OF THE PERIOD THU AFTERNOON. 

.GULF OF PANAMA...NEAR GALE FORCE TRADE WINDS IN THE CARIBBEAN 
ALONG THE COAST OF COLOMBIA ARE SIPHONING INTO THE GULF OF 
PANAMA AND ARE EXPECTED TO REACH A FRESH TO STRONG N BREEZE THIS 
EVENING. THESE WINDS WILL SHIFT S-SW AWAY FROM THE GULF OF 
PANAMA TONIGHT AS THE LOW OVER N COLOMBIA SHIFTS W. THE WINDS 
WILL DIMINISH BELOW ADVISORY CRITERIA BY SUNRISE WED. 

$$
SCHAUER