Tropical Weather Discussion
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000
AXPZ20 KNHC 280320
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT FEB 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0315 UTC.

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC...NORTHERLY 25-35 KT MINIMAL GALE FORCE
WINDS ARE EXPECTED TO PERSIST TILL LATE TONIGHT WITH SEAS
BUILDING TO A MAX OF 13 FT NEAR 14.5N95W. THE NORTHERLY WINDS
WILL DIMINISH BELOW GALE FORCE EARLY SAT. LATEST GUIDANCE HAS
BACKED ON THE STRENGTH OF THE SECONDARY SURGE...AND NOW EXPECT
THE NORTHERLY SURGE TO MAX AT 30 KT ON SAT NIGHT WITH SEAS
BUILDING TO ABOUT 11 FT. NORTHERLY WINDS ARE THEN EXPECTED TO
CONTINUE AT 20-25 KT THROUGH SUNRISE ON TUE.

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

A LOW LEVEL TROUGH EXTENDS W FROM THE PACIFIC COAST OF COLOMBIA
AT 04N77W TO 05N99W WHERE SCATTEROMETER WINDS INDICATE THAT THE
ITCZ FORMS AND THEN CONTINUES NW TO AN EMBEDDED TROUGH AT
07N118W...THEN CONTINUES W TO BEYOND 07N140W. SCATTERED MODERATE
CONVECTION IS OBSERVED ALONG THE LOW LEVEL TROUGH WITHIN 75 NM
EITHER SIDE OF A LINE FROM 05N84W TO 03N90W. SIMILAR CONVECTION
IS NOTED N OF THE ITCZ WITHIN 240 NM EITHER SIDE OF A LINE FROM
11N121W TO 08N140W.

A TROUGH IS EMBEDDED WITHIN THE ITCZ FROM 07N118W TO 12N117W.
SCATTERED MODERATE CONVECTION IS NOTED N OF 11N WITHIN 90 NM
E AND WITHIN 240 NM W OF THE TROUGH AXIS.

...DISCUSSION...

A POSITIVE TILT UPPER TROUGH HAS ITS MEAN AXIS EXTENDING SW
FROM OVER ARIZONA THROUGH 21N120W TO A BASE OVER THE DEEP
TROPICS AT 10N135W. AN UPPER RIDGE EXTENDS WSW FROM THE SW
CARIBBEAN TO AN ILL-DEFINED CREST NEAR 07N107W. UPPER DIFFLUENCE
BETWEEN THE TROUGH AND THE RIDGE IS ENHANCING THE ITCZ RELATED
CONVECTION PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS MOISTURE
IS ADVECTED NE CONCENTRATING INTO INTO A 480 NM WIDE PLUME THAT
CONTINUES ENE ACROSS CENTRAL MEXICO...THE GULF OF MEXICO AND
ACROSS MOST OF FLORIDA. DEBRIS MOISTURE FROM THE SMALL CLUSTERS
OF CONVECTION DESCRIBED ALONG THE EASTERN PORTION OF THE ITCZ
QUICKLY EVAPORATES IN THE DRY UPPER AIR DOMINATING THE TROPICS
TO THE E OF 106W.

A SURFACE RIDGE EXTENDS FROM 32N137W TO 13N98W. A BROAD MIX OF
SWELLS HAS RESULTED COMBINED SEAS OF 7-9 FT ACROSS THE PACIFIC
WATERS W OF 133W. THE SWELLS WILL GRADUALLY SUBSIDE BELOW 8 FT
LATER TONIGHT. NORTHERLY WINDS TO THE NE OF THE RIDGE ARE HAVE
SUBSIDED TO 10-15 KT...BUT THE ASSOCIATED NW SWELLS ARE REACHING
THE PACIFIC COAST OF THE NORTHERN BAJA PENINSULA IN THE FORM OF
5-8 FT SEAS. THESE SEAS ARE EXPECTED TO SUBSIDE TO 4-6 FT ON
SAT. GUIDANCE INDICATES THAT A BATCH 20-25 KT NORTHERLY
WINDS...WITH 8-11 FT SEAS...WILL MOVE INTO THE NORTHERN WATERS
BETWEEN 125-135W ON SAT NIGHT...AND SHIFT SW TO ALONG 22N ON SUN
NIGHT.

GULF OF CALIFORNIA...S-SW 10-15 KT WINDS CURRENTLY OBSERVED
OVER THE NORTHERN GULF OF CALIFORNIA WILL INCREASE TO 20-25 KT
LATER TONIGHT...AND CONTINUE THROUGH SAT NIGHT...THEN RELAX TO
10-15 KT AHEAD OF A WEAK TROUGH ARRIVING IN THE NORTHERN GULF
ON MON NIGHT. THE TROUGH WILL PASS THROUGH THE CENTRAL GULF OF
CALIFORNIA ON TUE WITH ONLY A 5-10 KT SW-W-NW WIND SHIFT.

GULF OF PAPAGAYO...NOCTURNAL 20-25 KT NE SURGES ARE EXPECTED TO
RESUME TONIGHT...WITH A SIGNIFICANT EVENT OCCURRING ON SUN AND
MON NIGHTS.

.GULF PANAMA...NORTHERLY 10-15 KT WINDS EXPECTED EACH NIGHT TILL
MON NIGHT WHEN GUIDANCE IS SUGGESTING AN INCREASE TO 20-25 KT.

$$
NELSON



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