Tropical Weather Discussion
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000
AXPZ20 KNHC 300249
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON MAR 30 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
0200 UTC.

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

A WEAK TROUGH EXTENDS FROM 04.5N845W TO 04N95W...THEN
TRANSITIONS TO ITCZ...CONTINUING ON TO 06N116W TO 07N140W.
SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 240 NM N OF
TROUGH BETWEEN 84W AND 89W. SCATTERED MODERATE ISOLATED STRONG
CONVECTION NOTED WITHIN 180 NM OF ITCZ BETWEEN 111W AND 127W.
SCATTERED MODERATE CONVECTION NOTED WITHIN 180 NM N OF ITCZ W OF
135W. SCATTERED MODERATE TO STRONG CONVECTION NOTED FROM 10N TO
14N BETWEEN 131W AND 139W.

DURING LATE WINTER TO EARLY SPRING SEASONS...FROM LATE FEBRUARY
TO EARLY APRIL...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. THIS EVENING...A TROUGH CONTINUES TO BE ANALYZED S OF
THE EQUATOR...CURRENTLY FROM 04S83W TO 03.5S98W. SCATTERED
MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 01S TO 07S
BETWEEN 83W AND 95W. COMPUTER MODEL GUIDANCE SUGGESTS AN ACTIVE
SOUTHERN ITCZ OVER THE NEXT 24-48 HOURS.

...DISCUSSION...

A 1028 MB HIGH PRES CENTER WAS LOCATED N OF AREA NEAR 34.5N134W
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 8-11 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...WHILE TO FRONT WILL SHIFT E AND
REMAIN N OF THE AREA.

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 25 KT
OCCURRING N OF 15N...WHERE MAX SEAS ARE 10 FT. WINDS HAVE
ALREADY VEERED TO SE ACROSS THE WESTERN GULF OF MEXICO...AND
ADDITIONAL GALES ARE NOT EXPECTED DURING THE NEXT SEVERAL 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 TO FADE ACROSS MUCH OF THE
FORECAST AREA...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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