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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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