000
AXPZ20 KNHC 040928
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAY 04 2007

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...ITCZ...
AXIS ALONG 9N77W 8N94W 7N99W 11N113W 6N133W 5N140W. SCATTERED 
MODERATE CONVECTION WITHIN 30 NM EITHER SIDE OF A LINE FROM 
4N78W TO 8N90W TO 7N99W AND FROM 8N107W TO 5N114W. SCATTERED 
STRONG CONVECTION WITHIN 50 NM OF 11N109W AND 10N119W. SCATTERED 
MODERATE WITHIN 20 NM OF A LINE FROM 9N121W TO 7N132W.

...DISCUSSION...

BROAD MID LEVEL TROUGHING CONTINUES BETWEEN 100W AND 125W DUE TO 
A LARGE NEG TILTED TROUGH IN THE NRN BRANCH OVER THE WRN CONUS. 
A FLAT MID LEVEL RIDGE COVERS THE AREA BETWEEN 10N AND 22N FROM 
95W TO 130W. WEAK IMPULSES AT MID LEVELS ARE WORKING THEIR WAY 
INTO THE REGION FROM THE S CENTRAL PACIFIC. ONE OF WHICH IS NEAR 
23N132W MOVING NE 15 KT AND ANOTHER SW OF THE REGION NEAR 
14N152W MOVING ENE 15 KT. ON THE SURFACE TONIGHT A MODERATELY 
STRONG PACIFIC RIDGE IS CENTERED NEAR 32N143W AT 1030 MB. THE 
RIDGE IS PRODUCING NW WINDS OF 25 KT ALONG THE UPPER BAJA COAST 
AND THIS IS CONFIRMED BY QUIKSCAT AND SSMI DATA. SHIP DATA SHOWS 
20 KT FURTHER S ALONG THE BAJA COAST WITH NW SWELL TO 13 FT. THE 
RIDGE IS ALSO PRODUCING A LARGE AREA OF NE TRADES TO 25 KT 
BETWEEN 6N AND 25N W OF 125W. 

LATER DAY 1 THE MID LEVEL TROUGHING WILL PERSIST WITH LITTLE 
CHANGE TO THE FLAT RIDGE OVER THE AREA. MID LEVEL RIDGING 
STRENGTHENS ALONG 140W NEAR 32N. WEAK IMPULSES CONTINUE TO WORK 
THEIR WAY INTO THE REGION FROM 20N140W TO 22N120W AND EWD TO 
CENTRAL MEXICO. ON THE SURFACE LATER DAY 1 LITTLE CHANGE OVER 
THE REGION ALTHOUGH THE GFS MODEL SHOWS WINDS ALONG THE BAJA 
COAST DECREASING SLIGHTLY. WAVE GUIDANCE SHOWS SEAS TO 12 FT 
PERSISTING ALONG THE BAJA COAST. ELSEWHERE GAP WINDS REMAIN 
LIGHT.

FOR DAY 2 SOME SHARPENING OF THE MID LEVEL TROUGH BETWEEN 100W 
AND 125W AS A NEW SURGE OF COLD AIR ENTERS THE CIRCULATION OVER 
THE WRN CONUS. THIS WILL SERVE TO INTERCEPT THE WEAK IMPULSES 
MOVING IN FROM THE S PACIFIC. MID LEVEL RIDGING REMAINS 
STATIONARY NEAR 33N137W AND BETWEEN 10N AND 18N..SOMEWHAT 
DEPRESSED SWD BY THE STRENGTHENED TROUGH. ON THE SURFACE DAY 2 
THE CENTER OF THE PACIFIC RIDGE REMAINS FAIRLY STRONG AT 1030 MB 
CENTERED NEAR 34N139W AND RIDGING SE OVER THE REGION TO 15N105W. 
NW WINDS ALONG THE BAJA COAST WILL REMAIN GUSTY AT 20 KT WITH NW 
SWELL OF 9 TO 12 FT. LITTLE CHANGE TO NE TRADES WITH WINDS NE 20 
TO 25 KT AND SEAS 9 TO 11 FT. GAP WINDS REMAIN LIGHT WITH LITTLE 
PRES GRADIENT ALONG THE CENTRAL AMERICAN COAST.

$$
RRG