Tropical Weather Discussion
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000
AXPZ20 KNHC 281004
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT MAR 28 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0915 UTC.

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC GALE WARNING...A STRONG COLD FRONT HAS MOVED
ACROSS THE WESTERN HALF OF THE GULF OF MEXICO. IT BROUGHT GALE-
FORCE WINDS INTO THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO
YESTERDAY AROUND 27/1200 UTC. IT HAS BROUGHT GALE-FORCE WINDS
INTO THE GULF OF TEHUANTEPEC. THOSE GALE-FORCE WINDS WILL LAST
FOR THE NEXT 24 HOURS OR SO. THE SEA HEIGHTS ARE EXPECTED TO
RANGE FROM 12 FEET TO 16 FEET DURING THE NEXT 24 HOURS OR SO. AN
AREA OF MIXED SWELL WILL RESULT IN 24 HOURS DOWNSTREAM FROM THE
AREA OF THE GULF OF TEHUANTEPEC GALE EVENT.

...GALE WARNING...
.WITHIN 30 NM ON EITHER SIDE OF LINE FROM 15.5N95W TO
14N95.5W...INCLUDING THE GULF OF TEHUANTEPEC...N WINDS 30 TO 40
KT. SEAS 12 TO 16 FT. ELSEWHERE N OF 13.5N BETWEEN 93.5W AND 96W
N TO NE WINDS 20 TO 30 KT. SEAS 8 TO 12 FT. REMAINDER OF AREA S
OF 18N BETWEEN 90W AND 122W WINDS 20 KT OR LESS. SEAS 8 TO 11 FT
IN SW SWELL.
.24 HOUR FORECAST N OF 13N BETWEEN 94W AND 97W...INCLUDING THE
GULF OF TEHUANTEPEC...N WINDS 25 TO 35 KT. SEAS 9 TO 13 FT.
ELSEWHERE FROM 05N TO 20N BETWEEN 90W AND 105W WINDS 20 KT OR
LESS. SEAS 8 TO 10 FT IN MIXED NE...NW AND SW SWELL.
.48 HOUR FORECAST N OF 14N BETWEEN 94W AND 96W...INCLUDING THE
GULF OF TEHUANTEPEC...N WINDS 20 TO 30 KT. SEAS 8 TO 9 FT.

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

A SURFACE TROUGH IS ALONG 14N129W TO 10N131W TO 05N132W.
CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG
FROM 07N TO 12N BETWEEN 125W AND 129W...AND FROM 07N TO 12N
BETWEEN 131W AND 132W.

A FIRST SURFACE TROUGH IS ALONG 06N87W TO 05N99W. A SECOND
SURFACE TROUGH IS ALONG 02N102W TO 05N108W TO 04N118W TO
06N125W. ITCZ FROM 06N133W BEYOND 05N140W. CONVECTIVE
PRECIPITATION...NUMEROUS STRONG FROM 06N TO 07N BETWEEN 82W AND
83W...AND FROM 02N TO 06N BETWEEN 102W AND 109W. SCATTERED
STRONG FROM 10N TO 11N BETWEEN 109W AND 111W...AND FROM 08N TO
09N BETWEEN 112W AND 113W. SCATTERED MODERATE TO ISOLATED STRONG
WITHIN 60 NM EITHER SIDE OF THE FIRST TROUGH...06N87W 05N99W...
BETWEEN 86W AND 98W. SCATTERED MODERATE FROM THE ITCZ TO 10N
BETWEEN 134W AND 140W.

...DISCUSSION...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N132W TO A
CYCLONIC CIRCULATION CENTER THAT IS NEAR 28N132W...TO 23N135W...
CONTINUING AS A SHEAR AXIS BEYOND 18N140W. THE TROUGH SUPPORTS A
DISSIPATING COLD FRONT THAT PASSES THROUGH 30N130W TO 27N134W.
THE FRONT WILL BE DISSIPATED COMPLETELY BY THE NEXT 24 HOURS.
THE WIND SPEEDS WILL BE 20 KNOTS OR LESS. SEA HEIGHTS WILL REACH
9 FEET IN NW SWELL...EVENTUALLY COVERING AN AREA THAT INCLUDES
FROM 20N NORTHWARD FROM 120W WESTWARD.

A SURFACE RIDGE EXTENDS FROM A 1032W MB HIGH PRESSURE CENTER
THAT IS NEAR 35N136W...THROUGH 32N133W...TO 26N129W TO
22N122W...AND TO 18N110W. AN AREA OF TRADEWIND FLOW WILL INCLUDE
NE WINDS 20 TO 25 KNOTS AND 8 TO 9 FOOT SEA HEIGHTS FROM 10N TO
20N FROM 122W WESTWARD. ALTIMETER OBSERVATIONS IN THIS AREA
DURING THE LAST 24 TO 36 HOURS HAVE BEEN SHOWING THAT COMPUTER
MODEL WAVE FORECASTS HAVE BEEN A FEW FEET LOW...AND THAT SEAS OF
9-11 FT DOMINATE THE WATERS. THIS HAS BEEN RELATED TO A VERY
LONG PERIOD SOUTHERN HEMISPHERE SWELL. THE PEAK OF THIS SWELL
WILL REACH THE CENTRAL AMERICAN AND MEXICAN COASTLINES THROUGH
BAJA CALIFORNIA TODAY...AND GENERATE VERY LARGE AND POWERFUL
WAVES...AND DANGEROUS CONDITIONS WITHIN THE SURF ZONE.

GAP WINDS...

THE GULF OF PAPAGAYO...EXPECT INCREASING WIND SPEEDS OF 20 TO 25
KNOTS IN THIS AREA DURING THE MORNING-TO-MIDDAY HOURS FROM
SUNDAY UNTIL WEDNESDAY...AS HIGH PRES BUILDS ACROSS THE NW
CARIBBEAN SEA AND IN NORTHERN CENTRAL AMERICA.

$$
MT



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