Tropical Weather Discussion
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000
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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