000
AXPZ20 KNHC 100956
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI APR 10 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 
0915 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 08N84W 
TO 04N97W TO 01N107W TO 01N123W TO 04N140W. NO SIGNIFICANT 
CONVECTION IS NOTED.

...DISCUSSION...

A BROAD AREA OF TRADE WINDS IS BEING ENHANCED ON THE SOUTHERN 
PERIPHERY OF A BROAD SURFACE RIDGE OVER THE NW QUARTER OF THE 
DISCUSSION AREA. NE WINDS TO 20 KT ARE PRESENT FROM 08N TO 21N W 
OF 120W BASED ON THE QUIKSCAT PASS AROUND 10/0600 UTC. COMPUTER 
MODEL GUIDANCE INDICATES THESE WINDS SLOWLY SINKING 
SOUTHEASTWARD DURING THE NEXT FEW DAYS AS A SURFACE RIDGE N OF 
THE DISCUSSION AREA SLOWLY TRANSLATES EAST-SOUTHEASTWARD. 
SATELLITE IMAGERY AND SCATTEROMETER DATA INDICATE THREE INVERTED 
TROUGHS LOCALLY ENHANCING THESE WINDS...THE WESTERN TROUGH 
EXTENDING FROM 11N135W TO 07N136W...THE CENTRAL TROUGH EXTENDING 
FROM 09N124W TO A 1012 MB SURFACE LOW NEAR 05N126W TO 
01N126W...AND THE EASTERN TROUGH EXTENDING FROM 15N115W TO 
09N118W. THE CENTRAL TROUGHS AND SURFACE LOW ARE BEST 
DEFINED...AND ENHANCED BOUNDARY LAYER MOISTURE CONVERGENCE NEAR 
THESE FEATURES...COMBINED WITH ATMOSPHERIC INSTABILITY BENEATH A 
MID/UPPER-LEVEL TROUGH...IS SUPPORTING SCATTERED SHOWERS AND 
THUNDERSTORMS FROM 02N TO 05N BETWEEN 123W AND 127W. ALSO... 
SURFACE PRESSURE FALLS OVER MEXICO DURING THE NEXT FEW 
DAYS...COMBINED WITH LOCAL TOPOGRAPHICAL EFFECTS...WILL LOCALLY 
ENHANCE NORTHWESTERLY WINDS NEAR THE COAST OF BAJA CALIFORNIA S 
OF 27N AND NEAR THE COAST OF MEXICO FROM 17N TO 21N. WINDS WILL 
LOCALLY REACH 20 KT IN THESE AREAS...AS RECENT ASCAT AND 
QUIKSCAT PASSES INDICATE. AS FOR WAVE HEIGHTS...A LARGE AREA OF 
SEAS OF 8 TO 10 FT IN GENERALLY NW SWELL WILL IMPACT MUCH OF THE 
DISCUSSION AREA DURING THE NEXT FEW DAYS...RESULTING FROM 
PREVIOUS STORM COMPLEXES OUTSIDE OF THE DISCUSSION AREA.

A SHORTWAVE TROUGH CURRENTLY OVER THE E PACIFIC CONTINUES TO 
DIVE SOUTHWARD WHILE DEEPENING...AS A VIGOROUS MID/UPPER-LEVEL 
JET FORCES IT TO DIG SOUTHWARD. COMPUTER MODEL GUIDANCE 
INDICATES THAT A SURFACE TROUGH...CURRENTLY EXTENDING FROM 
30N125W TO 28N130W TO 28N136W...WILL MOVE ACROSS THE 
NORTHEASTERN WATERS DURING THE NEXT COUPLE DAYS...WITH STRONG 
WINDS ON EITHER SIDE OF THE TROUGH. THIS TROUGH IS THE REMNANT 
OF A COLD FRONT PREVIOUSLY N OF THE DISCUSSION AREA. GUIDANCE 
ALSO INDICATES THAT A SURFACE LOW OVER THE SW CONUS WILL 
STRENGTHEN THE SURFACE PRESSURE GRADIENT NEAR THE REMNANT 
TROUGH. THIS WILL BRING THE THREAT FOR W TO NW WINDS UP TO 30 KT 
NEAR THE REMNANT TROUGH. THE TROUGH WILL IMPACT THE N GULF OF 
CALIFORNIA ON SATURDAY. WAVEWATCH GUIDANCE INDICATES SEAS 
BUILDING TO 13 FT W OF THE TROUGH OVER THE NE PACIFIC REGION.

GAP WINDS...
INCREASED TRADE WINDS OVER THE CARIBBEAN REGION ARE FORECAST TO 
EXTEND INTO THE GULF OF PAPAGAYO DURING THE NEXT FEW DAYS...WHEN 
SURFACE WINDS ARE EXPECTED TO OCCASIONALLY REACH 20 KT. 

$$
COHEN