000
AXPZ20 KNHC 290237
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC WED APR 29 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC. 

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC GALE WARNING...MODEL GUIDANCE IS IN GOOD 
AGREEMENT SHOWING WEAK LOW PRES DEVELOPMENT SE OF TEHUANTEPEC 
AND HIGH PRES BUILDING OVER EASTERN MEXICO WED NIGHT. THIS WILL 
RESULT IN THE TIGHTENING OF THE PRES GRADIENT ACROSS THE ISTHMUS 
TO SUPPORT MINIMAL GALE CONDITIONS IN THE GULF OF TEHUANTEPEC 
THROUGH THU MORNING. SEAS DURING THIS PERIOD WILL BUILD UP TO 13 
FT. GFS MODEL GUIDANCE SHOWS POSSIBILITY OF ANOTHER BRIEF SHOT 
OF GALE FORCE WINDS N OF 15N THU NIGHT.

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

MONSOON TROUGH EXTENDS FROM 08N78W TO 05N84W TO 05N93W TO 1007 
MB LOW AT 11N104W. ITCZ EXTENDS FROM 07N120W TO 05N130W TO 
05N140W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 02N TO 
08N BETWEEN 78W AND 101W. SCATTERED MODERATE CONVECTION IS FROM 
02N TO 10N BETWEEN 111W AND 140W. 

...DISCUSSION...    

WATER VAPOR IMAGERY SHOWS A MID-UPPER LEVEL TROUGH EXTENDING W 
FROM TEXAS-OKLAHOMA BORDER ACROSS NW MEXICO AND THE CENTRAL BAJA 
PENINSULA TO 26N126W THEN S-SW TO 13N127W. DRY STABLE AIR ALOFT 
IS W OF THE TROUGH AND A SWATH OF TROPICAL MOISTURE IS BEING 
ADVECTED SE OF THE TROUGH FROM ACTIVE CONVECTION OCCURRING E OF 
A LOW PRESSURE CENTER BETWEEN 99W-112W. THE SUBTROPICAL HIGH 
CONTINUES TO WEAKEN AN ADVANCING COLD FRONT THAT EXTENDS FROM 
THE CALIFORNIA COAST AT 38N123W TO 30N133W TO 28N140W. NW SWELL 
BEHIND THE COLD FRONT HAS REACHED THE NW PORTION OF THE AREA. 
THE SWELL WILL SUBSIDE WED AS THE DISSIPATING COLD FRONT WEAKENS 
TONIGHT. ANOTHER SURGE OF N-NW SWELL ASSOCIATED WITH STRONG N 
WINDS ALONG THE CALIFORNIA COAST WILL SWEEP S OF 30N INTO NE 
PORTION OF THE AREA WED NIGHT THROUGH THU MORNING.

LOOKING AHEAD...VERY LARGE AREA OF CROSS-EQUATORIAL LONG PERIOD 
SW SWELL WILL BEGIN TO AFFECT S AND SE PORTIONS THU NIGHT AND 
FRI WITH SEAS 9-10 FT AND 19-20 SEC PERIOD. THIS SWELL WILL 
REACH THE WEST COAST OF CENTRAL AMERICA THIS WEEKEND...WITH 
LARGE SURF LIKELY FROM PANAMA TO CENTRAL MEXICO.

$$
FORMOSA