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AXPZ20 KNHC 292218
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN MAR 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC.


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

A WEAK TROUGH EXTENDS FROM LOW PRES 1011 MB NEAR 06N77.5W TO 03N93W... THEN TRANSITIONS TO ITCZ...CONTINUING ON TO 06N112W TO 07N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 240 NM N OF TROUGH BETWEEN 80W AND 91W. SCATTERED MODERATE TO STRONG WITHIN 330 NM N OF ITCZ BETWEEN 101W AND 124W. SCATTERED MODERATE WITHIN 120 NM EITHER SIDE OF ITCZ W OF 135W. SCATTERED MODERATE TO STRONG CONVECTION NOTED FROM 10N TO 14N BETWEEN 132W AND 137W.

DURING LATE WINTER TO EARLY SPRING SEASONS...FROM LATE FEBRUARY TO EARLY APRIL OF EACH YEAR...A MONSOONAL CIRCULATION IS TYPICALLY NOT PRESENT ACROSS THE TROPICAL NE PACIFIC...AND CAN BE BRIEFLY REPLACED BY A DOUBLE ITCZ STRUCTURE...ONE ON EACH SIDE OF THE EQUATOR. TODAY...A TROUGH CONTINUES TO BE ANALYZED S OF THE EQUATOR...CURRENTLY FROM 04S81W TO 03.5S96W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 01S TO 07.5S BETWEEN 83W AND 90W. COMPUTER MODEL GUIDANCE SUGGESTS AN ACTIVE SOUTHERN ITCZ OVER THE NEXT 24-48 HOURS.


...DISCUSSION...

A 1030 MB HIGH PRES CENTER WAS LOCATED N OF AREA NEAR 34.5N133W AND EXTENDS A RIDGE SE ACROSS THE FORECAST WATERS TO NEAR 18N120W. SOUTH OF THE RIDGE...THE PRES GRADIENT BETWEEN THE HIGH AND LOWER PRES ALONG THE ITCZ IS RESULTING IN FRESH TO STRONG NE TRADEWINDS FROM 08N TO 24N W OF 120W...WHERE SEAS ARE 8-12 FT IN MIXED NE WIND WAVES AND LONG PERIOD CROSS EQUATORIAL SOUTHERLY SWELL. THE AERIAL EXTENT OF THE TRADES WILL DECREASE ON MON AS HIGH PRES MOVES SW AND WEAKENS AHEAD OF AN APPROACHING COLD FRONT. THE HIGH IS FORECAST TO SHIFT SW ACROSS THE FAR NW CORNER OF THE AREA BY MON MORNING.

LIGHT TO MODERATE NE TO E WINDS PREVAIL ACROSS MOST OF THE AREA E OF 120W...WHERE A WEAK TROUGH AND ASSOCIATED CONVECTION DESCRIBED ABOVE ARE PRESENT. THE EXCEPT TO THIS REMAINS ACROSS THE GULF OF TEHUANTEPEC. GALE FORCE WINDS HAVE ENDED ACROSS THIS GULF LATE THIS MORNING...AND HAVE DIMINISHED TO 20 TO 30 KT OCCURRING N OF 14N...WHERE MAX SEAS ARE 11 FT. WINDS HAVE ALREADY VEERED TO SE ACROSS THE WESTERN GULF OF MEXICO...AND ADDITIONAL GALES ARE NOT EXPECTED DURING THE NEXT FEW DAYS. FRESH TO STRONG NORTHERLY WINDS ARE EXPECTED TO PERSIST ACROSS THE GULF OF TEHUANTEPEC AND DOWNWIND FOR ABOUT 200 NM THROUGH TUESDAY...WITH NOCTURNAL DRAINAGE FLOW ENHANCING THE WINDS TO NEAR 30 KT EACH NIGHT.

LONG PERIOD SOUTHERLY SWELL CONTINUES ACROSS MUCH OF THE FORECAST AREA...AND HAVE BEEN REACHING THE CENTRAL AMERICAN AND MEXICAN COASTLINES THROUGH BAJA CALIFORNIA FOR THE PAST 2 DAYS. THESE SWELLS HAVE BEGUN TO FADE DURING THE PAST 24 HOUR AND WILL DIMINISH TO 4 FT OR LESS ON MONDAY. ADDITIONAL PULSES OF NW SWELL ARE REACHING THE FAR NW PART OF THE FORECAST REGION AND WILL MIX WITH THE SOUTHERLY SWELL ALREADY IN PLACE TO BUILD SEAS TO 9 FT ACROSS THE N WATERS DURING THE NEXT COUPLE OF DAYS. EXPECT SEAS OF 8-9 FT PRIMARILY IN NW SWELL NW OF LINE FROM 30N118W TO 23N130W TO 18N140W BY TUE MORNING.

GAP WINDS...

THE GULF OF PAPAGAYO...PULSING OF NOCTURNAL WINDS ARE EXPECTED ACROSS THE GULF OF PAPAGAYO THROUGH TUE MORNING...REACHING 20-25 KT FROM 0600 TO 1200 UTC...WITH SEAS OF 7-8 FT THROUGH AND DOWNWIND OF THE GULF.

$$ STRIPLING

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