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Eastern Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 012145
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC WED APR 01 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 
2145 UTC. 

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

THE ITCZ WAS ANALYZED FROM 02N102W TO 00N117W WITH ONLY ISOLATED 
MODERATE CONVECTION FLARING INTERMITTENTLY ALONG ITS AXIS. 

A SURFACE TROUGH EXTENDS SW OFF THE COAST OF COLOMBIA FROM 
05N77W TO 01N82W. 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 02N99W. ISOLATED MODERATE TO STRONG CONVECTION
IS OBSERVED WITHIN 120 NM EITHER SIDE OF A LINE FROM
08.5N83.5W TO 01N97.5W. 

A THIRD TROUGH IS NOTED IN THE DEEP TROPICS FROM 14N124W TO
03N123W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
E OF THE TROUGH WITHIN 120 NM EITWRKHER SIDE OF A LINE FROM 
08N123W TO 13.5N121W.    

SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 30 NM EITHER 
SIDE OF A LINE FROM 01N120W TO 08N122W. ISOLATED MODERATE TO 
STRONG CONVECTION IS NOTED WITHIN 60 NM OF LINE FROM 09N126W 
TO 07N135W.   

...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 NORTHERN MEXICO... 
AND THE WESTERNMOST TROUGH IS JUST W OF THE DISCUSSION AREA 
ALONG 144W. A WEAK UPPER RIDGE IS NOTED BETWEEN THESE TROUGHS 
WITH NEARLY ZONAL 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 22N122W TO 
08N126W. AN ASSOCIATED LOW LEVEL TROUGH EXTENDS FROM 14N124W TO 
03N123W...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 112-124W 
TO ALONG 21N...THEN TURNS NE AND LATER E IN THE UPPER ZONAL 
FLOW...WITH THE MOISTURE CONTINUING E ACROSS CENTRAL MEXICO. IT 
APPEARS THAT THE LOW AND UPPER FEATURES ARE DECOUPLING....AND 
SHOULD EXPECT A DECREASE IN CONVECTION.  

AN UPPER ANTICYCLONE IS OVER NW COLOMBIA WITH AN UPPER RIDGE 
EXTENDING NW TO A CREST AT 20N119W. 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 32N130W TO 
14N97W. 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 THU...THEN THE GRADIENT WILL RELAX WITH 
WINDS DIMINISHING TO 20 KT OR LESS BY FRI NIGHT. 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 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: Wednesday, 01-Apr-2015 21:45:43 UTC