000
AXPZ20 KNHC 150947
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED APR 15 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0930 UTC.

...ITCZ...

ITCZ AXIS CAN BE FOUND ALONG A LINE FROM 06N77W TO 07N120W TO 
04N140W. NO SIGNIFICANT CONVECTION NOTED.

...DISCUSSION...

N OF 20N...
A DEEP LAYER TROUGH EXTENDS FROM THE GREAT BASING ALONG 115W 
THROUGH NORTHERN BAJA. THIS IS SUPPORTING A COLD FRONT MOVING 
ACROSS SOUTHERN CALIFORNIA AND NORTHERN BAJA...AND WILL SHIFT 
THROUGH THE NORTHERN PORTION OF THE GULF OF CALIFORNIA BY LATE 
TODAY. A QUIKSCAT PASS FROM 02Z INDICATED 20 TO 25 KT SW WINDS 
OVER THE NORTHERN GULF OF CALIFORNIA AHEAD OF THE FRONT. A 0430Z 
ASCAT PASS SHOWED 20 TO 25 KT NORTHERLY FLOW ALONG THE NORTHERN 
BAJA COAST BEHIND THE FRONT...AND AHEAD OF 1031 MB SURFACE HIGH 
PRES NEAR 37N134W MOVING EASTWARD. THE STRONG NORTHERLY WINDS 
WILL EXTEND THE LENGTH OF THE BAJA COAST BEHIND THE FRONT AND 
AHEAD OF THE SURFACE HIGH THROUGH TONIGHT...THEN DIMINISH THU 
INTO FRI AS THE HIGH PRES NEARS. THE 20 TO 25 KT WINDS OVER THE 
NORTHERN GULF OF BAJA WILL PERSIST THROUGH THE NIGHT BUT VEER 
MORE NW...THEN DIMINISH THURSDAY. LONG PERIOD NORTHERLY SWELL 
WITH HEIGHTS TO 17 FT WILL PUSH INTO THE WATERS MAINLY EAST OF 
130W...THEN DECAY TO 10 FT OR LESS BY LATE THU. MEANWHILE TRADE 
WINDS IN EXCESS OF 20 KT WILL PERSIST S OF 25N...S OF THE 
SURFACE HIGH PRES.

S OF 20N...
AN ASHFALL ADVISORY IS IN EFFECT FROM THE ONGOING ERUPTION OF 
THE FERNANDINA VOLCANO NEAR 0.4S91.5W. THE GOVERNMENT OF ECUADOR 
IS FLYING RECONNAISSANCE MISSIONS TO INVESTIGATE THE ERUPTION. 
ON THE RECOMMENDATION OF THE NESDIS SATELLITE ANALYSIS 
BRANCH...THE ASHFALL ADVISORY WAS EXTENDED THROUGH 48 HOURS DUE 
TO THE UNCERTAINTY IN THE TIMING OF THE END OF THE VOLCANIC 
ACTIVITY. WINDS ARE EXPECTED TO REMAIN EAST TO SE NEAR 10 KT IN 
THIS AREA DURING THAT TIME. MARINERS SHOULD EXERCISE CAUTION DUE 
TO THE POTENTIAL FOR REDUCED VISIBILITIES CAUSED BY VOLCANIC 
ASH  DOWNWIND OF THE VOLCANO S OF 02N BETWEEN 93W AND 95W FOR AT 
LEAST THE NEXT FEW DAYS. IN ADDITION...NASA OMI IMAGERY FROM 
2306 UTC SHOWS A LARGE PLUME OF ELEVATED LEVELS OF SULFUR 
DIOXIDE FROM 02S TO 05N BETWEEN 91W AND 103W. EXPOSURE TO SULFUR 
DIOXIDE GAS CAN BE DANGEROUS AND CAUSE SKIN AND EYE IRRITATION.

ELSEWHERE...SCATTEROMETER DATA INDICATED A BROAD SWATH OF 20 KT 
TRADE WINDS MAINLY W OF 125W. LITTLE CHANGE IS ANTICIPATED OVER 
THE NEXT COUPLE OF DAYS AS SURFACE HIGH PRES TO THE NORTH SHIFTS 
INTO THE AREA. SEAS ARE RUNNING 8 TO 10 FT WITH NE SWELL IN AN 
AREA FROM 13N TO 20N. THIS DECAYS THROUGH TODAY...JUST AS 
ANOTHER NORTHERLY SWELL GROUP PUSHES THROUGH THE AREA MAINLY E 
OF 130W OVER THE NEXT COUPLE OF DAYS. MEANWHILE WEAK DIVERGENCE 
ALOFT ON THE EAST SIDE OF AN UPPER ANTICYCLONE NEAR 07N115W IS 
SUPPORTING MODEST CONVECTION OVER THE ITCZ...BUT THIS IS RAPIDLY 
DIMINISHING.

$$
CHRISTENSEN