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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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