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AXPZ20 KNHC 291535
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC.


...SPECIAL FEATURES...

GULF OF TEHUANTEPEC GALE WARNING...GALE FORCE WINDS CONTINUE TO BLOW IN THE GULF OF TEHUANTEPEC EARLY THIS MORNING BASED ON THE MOST RECENT SCATTEROMETER PASS. IXTEPEC IN THE NORTHERN END OF THE GULF IS CURRENTLY REPORTING GUSTY WINDS TO 30 KT. WINDS HAVE ALREADY VEERED ACROSS THE WESTERN GULF OF MEXICO. THIS WILL DECREASE WINDS FUNNELING THROUGH THE CHIVELA PASS IN TO THE GULF OF TEHUANTEPEC. GLOBAL MODEL ALSO SUGGESTS DECREASING WINDS BELOW GALE FORCE BEGINNING THIS AFTERNOON. AS A RESULT...THE GALE WARNING WILL BE ALLOWED TO EXPIRE TODAY AT 1800 UTC. PERSISTENT NORTHERLY WINDS OF 20-30 KT WILL CONTINUE TO BE ENHANCED BY THE NOCTURNAL DRAINAGE FLOW DURING THE OVERNIGHT AND EARLY MORNING HOURS THROUGH TUE MORNING.


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

THE MONSOON TROUGH EXTENDS FROM 08N83W TO 04N95W. THE ITCZ CONTINUES FROM 04N95W TO 07N110W THEN RESUMES AT 08N113W TO 06N125W TO 09N134W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS FROM 04N TO 06N BETWEEN 88W AND 90W. SCATTERED MODERATE CONVECTION CAN BE FOUND FROM 05N TO 08N BETWEEN 110W AND 114W...FROM 08N TO 10N BETWEEN 127W AND 127W...AND FROM 02NTO 04N BETWEEN 124W AND 126W.

DURING LATE WINTER TO EARLY SPRING SEASONS...FROM LATE FEBRUARY TO EARLY APRIL OF EACH YEAR...A DOUBLE ITCZ CAN BE PRESENT ACROSS THE EASTERN PACIFIC...ONE ON EACH SIDE OF THE EQUATOR. TODAY...A TROUGH IS ANALYZED S OF THE EQUATOR FROM 03.4S84W TO 05S88W TO 04S93W. SCATTERED MODERATE CONVECTION IS SEEN ON SATELLITE IMAGERY FROM 02S TO 09S BETWEEN 83W AND 91W. COMPUTER MODEL SUGGESTS AN ACTIVE SOUTHERN ITCZ OVER THE NEXT 24-48 HOURS.


...DISCUSSION...

A 1029 MB HIGH PRES LOCATED N OF AREA NEAR 35N134W EXTENDS A RIDGE SE ACROSS THE FORECAST WATERS TO NEAR 20N114W. 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 13N TO 20N W OF 128W...WHERE SEAS ARE 8-12 FT IN MIXED NE WIND WAVES AND LONG PERIOD CROSS EQUATORIAL SOUTHERLY SWELLS. 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 REACH THE FAR NW CORNER OF THE AREA BY MON MORNING.

A SURFACE TROUGH IS ACROSS THE WEST CENTRAL WATERS AND EXTENDS FROM 14N136W TO A 1012 MB LOW PRES NEAR 11N136W TO NEAR 07N137W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS NOTED NEAR THE NORTHERN END OF THE TROUGH AXIS COVERING FROM 12N TO 14.5N BETWEEN 135W AND 138W. SIMILAR CONVECTION IS FROM 11N TO 12N BETWEEN 134W AND 135W. ANOTHER TROUGH...EMBEDDED WITHIN THE ITCZ LIES FROM 11N112W TO 04N111W. SCATTERED MODERATE CONVECTION IS FROM 09N TO 11N BETWEEN 112W AND 115W...AND NEAR 05N111W.

E OF 110W...WITH THE EXCEPTION OF THE GAP WIND REGIONS...WINDS ARE GENERALLY LIGHT TO GENTLE. UPPER LEVEL RIDGING ACROSS THE MAJORITY OF THE AREA IS HELPING TO INDUCE SOME CONVECTIVE ACTIVITY. A CLUSTER OF MODERATE TO STRONG CONVECTION IS NOTED FROM 04N TO 06N E OF 79W TO THE COAST OF COLOMBIA WITH A TROUGH JUST INLAND.

LONG PERIOD SOUTHERLY SWELL CONTINUES TO DOMINATE MUCH OF THE FORECAST WATERS...AND ARE REACHING THE CENTRAL AMERICAN AND MEXICAN COASTLINES THROUGH BAJA CALIFORNIA. THESE SWELLS ARE LIKELY GENERATING VERY LARGE AND POWERFUL WAVES...AND DANGEROUS CONDITIONS WITHIN THE SURF ZONE TODAY...BUT WILL GRADUALLY FADE DURING THE NEXT 24-36 HRS. PRESENTLY...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.

$$ GR

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