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Eastern Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 020232
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC THU APR 02 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 0230 UTC. 

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

THE ITCZ WAS ANALYZED FROM 04N95W TO 03N114W WITH ONLY ISOLATED 
MODERATE CONVECTION FLARING INTERMITTENTLY ALONG ITS AXIS. 

A SURFACE TROUGH EXTENDS SW OFF THE COAST OF COLOMBIA FROM 
05N77W TO 01N83W. SCATTERED MODERATE CONVECTION IS OBSERVED 
WITHIN 30 NM OF THE TROUGH. 

A SECOND TROUGH EXTENDS SW FROM THE COAST OF COSTA RICA AT 
10N85W TO 04N95W WHERE SCATTEROMETER WINDS INDICATE THAT THE 
ITCZ FORMS. ISOLATED MODERATE TO STRONG CONVECTION IS OBSERVED 
WITHIN 240 NM EITHER SIDE OF THE TROUGH AXIS. 

A THIRD TROUGH IS NOTED IN THE DEEP TROPICS FROM 07N125W TO 
13N126W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
E OF THE TROUGH WITHIN 120 NM EITHER SIDE OF A LINE FROM 
08N122W TO 14N122W.    

SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 30 NM EITHER 
SIDE OF A LINE FROM 03N120W TO 07N121W. ISOLATED MODERATE TO 
STRONG CONVECTION IS NOTED WITHIN 75 NM OF LINE FROM 06N128W 
TO 08N136W.   

...DISCUSSION... 

ALOFT...A PAIR OF WEAK UPPER LEVEL SHORT WAVE TROUGHS ARE  
OBSERVED OVER THE SUBTROPICAL PORTION OF THE DISCUSSION AREA. 
THE EASTERNMOST TROUGH IS PASSING E ACROSS WESTERN TEXAS AND  
NORTHERN MEXICO...AND THE WESTERNMOST TROUGH IS JUST W OF THE  
DISCUSSION AREA ALONG 143W. A WEAK UPPER RIDGE IS NOTED BETWEEN 
THESE TROUGHS WITH NEARLY ZONAL UPPER FLOW...WHICH IS ADVECTING 
A LARGE PLUME OF UPPER MOISTURE EASTWARD. THIS MOISTURE SHOULD 
PASS ACROSS THE NORTHERN BAJA CALIFORNIA PENINSULA AND GULF OF 
CALIFORNIA TONIGHT.  

AN UPPER TROUGH IS OBSERVED OVER THE TROPICS FROM 20N123W TO  
08N125W. AN ASSOCIATED LOW LEVEL TROUGH EXTENDS FROM 07N125W TO 
13N126W...AND WAS PREVIOUSLY DESCRIBED. UPPER LEVEL DIVERGENCE  
E OF THE UPPER TROUGH IS ENHANCING THE CONVECTION PREVIOUSLY 
MENTIONED...WITH THE DEBRIS MOISTURE ADVECTED N BETWEEN 113-121W 
TO ALONG 22N...THEN TURNS NE AND LATER E IN THE UPPER ZONAL 
FLOW...WITH THE MOISTURE CONTINUING E ACROSS CENTRAL MEXICO.  
THE SURFACE LOW AND UPPER TROUGH ARE DECOUPLING...AND A  
DECREASE IN CONVECTION IS ANTICIPATED.  

AN UPPER ANTICYCLONE IS OVER NW COLOMBIA WITH AN UPPER RIDGE 
EXTENDING NW TO A CREST AT 22N120W. DEBRIS MOISTURE FROM THE 
CONVECTION ASSOCIATED WITH THE SURFACE TROUGHS...PREVIOUSLY 
DESCRIBED...IS ADVECTED N AND NE ACROSS THE RIDGE AND OVER 
CENTRAL AMERICA.

AT THE LOW LEVELS A SURFACE RIDGE EXTENDS FROM 32N133W TO 
13N92W. THE PRESSURE GRADIENT E OF THE RIDGE IS SUPPORTING 
NORTHERLY 20-25 KT WINDS ACROSS THE DISCUSSION AREA FROM 29-32N  
BETWEEN 120-126W...WITH COMBINED SEAS OF 10-13 FT. LITTLE CHANGE 
EXPECTED TONIGHT AND EARLY THU...THEN THE GRADIENT WILL RELAX 
WITH WINDS DIMINISHING TO 20 KT OR LESS BY EARLY FRI. LONG 
PERIOD NW SWELL IS PROPAGATING SE ACROSS THE WATERS W OF 105W 
AND MIXING WITH LONG PERIOD CROSS-EQUATORIAL SWELL...AND 
ADDITIONALLY MIXING WITH LONG PERIOD NE TRADE SWELL ACROSS THE 
WATERS S OF THE RIDGE AND W OF 130W. THESE SWELLS WILL GRADUALLY 
SUBSIDE OVER THE UPCOMING WEEKEND...HOWEVER SEAS TO 8 FT WILL 
ARRIVE ALONG THE NW COAST OF THE BAJA CALIFORNIA PENINSULA ON 
SUN. 

GULF OF PAPAGAYO...EXPECT BRIEF NOCTURNAL DRAINAGE OF ENE 20-25 
KT WINDS TONIGHT...AND ON THU AND FRI NIGHTS. GUIDANCE SUGGESTS 
A SIGNIFICANT EVENT WILL OCCUR ON SAT AND SUN NIGHTS WITH 
THE WESTERN EXTENT REACHING NEAR 11N91W...WITH SEAS BUILDING TO
9 FT. 

GULF OF TEHUANTEPEC...EXPECT NORTHERLY 20-25 KT WINDS TO SURGE  
THROUGH THE ISTHMUS OF TEHUANTEPEC LATE FRI NIGHT...GRADUALLY 
INCREASE THROUGHOUT THE DAY ON SAT REACHING MINIMAL GALE FORCE 
ON SAT NIGHT THROUGH SUNRISE ON SUN.  

$$ 
NELSON

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Page last modified: Thursday, 02-Apr-2015 02:32:18 UTC