000
AXPZ20 KNHC 270320
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON APR 27 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0330 UTC.

...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 03N78W TO 06N100W TO 04N120W TO 
05N135W TO 03N140W. SCATTERED MODERATE/ISOLATED STRONG WITHIN 
ABOUT 180 NM N OF AXIS BETWEEN 117W AND 126W. SCATTERED MODERATE 
WITHIN 45 NM EITHER SIDE OF AXIS BETWEEN 128W AND 136W. SIMILAR 
CONVECTION IS NOTED FROM 06N TO 09N WEST OF 134W.


...DISCUSSION...
A TROUGH/RIDGE/TROUGH PATTERN COVERS MOST OF THE REGION WITH THE 
RIDGE AXIS ALONG 125W. A TROUGH EXTENDS ALONG THE SW U.S. AND NW 
MEXICO. A JET-STREAM BRANCH WITH CORE WINDS OF 70-100 KT ROUNDS 
THE BASE OF THIS TROUGH AFFECTING N BAJA PENINSULA AND THE FAR 
NE PORTION OF THE AREA. A STRONG SHORT-WAVE TROUGH REMAINS JUST 
W OF THE REGION. A BROAD PLUME OF DEEP LAYERED MOISTURE AND 
OVERCAST MULTI-LEVEL CLOUDS ASSOCIATED WITH THIS FEATURE COVERS 
MUCH OF THE AREA N OF 15N AND WEST OF 125W. SWLY FLOW AHEAD OF A 
SHORT-WAVE TROUGH OVER THE EASTERN BAY OF CAMPECHE AND THE 
ISTHMUS OF TEHUANTEPEC IS ADVECTING HIGH DEBRIS CLOUDINESS FROM 
THE ITCZ CONVECTION TOWARDS CENTRAL AMERICA INTO THE CARIBBEAN 
SEA. AN UPPER-LEVEL HIGH CENTERED NEAR 07N124W IS HELPING TO 
INDUCE MODERATE TO ISOLATED STRONG CONVECTION ALONG THE ITCZ 
AXIS WEST OF 115W. A SFC TROUGH IS ANALYZED ALONG 136W S OF 11N. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN ABOUT 
180 NM E OF THE TROUGH AXIS FROM THE ITCZ AXIS TO 08N.  

SURFACE LOW PRES ASSOCIATED WITH THE TROUGH W OF THE AREA IS 
FORECAST TO TRACK N OVER THE NEXT 24-36 HRS AS THE SHORTWAVE 
TROUGH LIFTS NE. SE WINDS OF 20-25 KT ON THE EAST SIDE OF THIS 
SFC LOW WILL CONTINUE TO IMPACT THE FAR NW CORNER OF THE REGION 
TONIGHT AND MON. 

HIGH PRES RIDGING EXTENDS SE INTO THE AREA FROM 31N132W TO 
17N110W. PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES OVER THE 
SW CONUS IS PRODUCING NW 20 KT OVER THE NE WATERS N OF 25N E OF 
120W TO THE COAST OF BAJA CALIFORNIA. AN ASCAT PASS FROM AROUND 
1800 UTC CONFIRMED THESE WIND SPEEDS. ACCORDING TO THE COMPUTER 
MODEL...THESE WINDS ARE FORECAST TO DIMINISH IN 24 HOURS...BUT 
WILL INCREASE AGAIN IN 48 HOURS AS A NEW HIGH PRES CENTER FORMS 
NEAR 35N130W...AND A 1002 SFC LOW DEVELOPS OVER THE SW U.S. 

TRADE WINDS IN THE 20 TO 25 KT RANGE COVER A LARGE PORTION OF 
THE AREA N OF THE ITCZ W OF ABOUT 115W. THESE WINDS ARE FORECAST 
TO DIMINISH IN AREAL COVERAGE AS THE RIDGE SLIGHTLY WEAKENS.

MOSTLY FAIR WEATHER PREVAILS ALONG THE MEXICAN COAST AND THE 
BAJA CALIFORNIA PENINSULA WITH ONLY A FEW SHOWERS OVER SE 
MEXICO. 

GAP WINDS...
NE-E WINDS OF 20 KT IN THE GULF OF PAPAGAYO ARE FORECAST TO 
PERSIST OVER THE NEXT 48 HRS WITH SEAS UP TO 8 FT.

$$
GR