000
AXPZ20 KNHC 170319
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE APR 17 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N77W 9N93W 5N110W 6N120W 4N140W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120NM N 
OF THE AXIS BETWEEN 94W-100W. SCATTERED MODERATE IS S OF THE 
AXIS FROM 4N-6N BETWEEN 94W-99W...AND WITHIN 300NM N OF AXIS 
BETWEEN 102W-111W AND BETWEEN 117W-127W. 

...DISCUSSION...
AT THE SURFACE...A 1041 MB HIGH IS CENTERED NW OF THE REGION 
NEAR 39N153W. THE HIGH IS RIDGING SE...BREAKING THROUGH A FRONT 
ALSO NW OF THE AREA. THIS IS PRODUCING MODERATE TO FRESH 
TRADEWINDS OVER MUCH OF THE AREA ESPECIALLY W OF 115W. ONLY 
SUBTLE CHANGES ANTICIPATED IN THIS PATTERN THROUGH MIDWEEK. 
HOWEVER...A BIT STRONGER SURGE OF NLY WINDS EXPECTED N OF 25N E 
OF 125W...OFF OF CALIFORNIA AND NRN BAJA...BY WED INTO THU. THE 
LATE SEASON GULF OF TEHUANTEPEC EVENT CONTINUES TO SUBSIDE 
STEADILY AND IS EXPECTED TO DIMINISH BELOW 20 KT BY TOMORROW 
AFTERNOON. SIMILAR WINDS IN THE GULF OF PAPAGAYO ALSO EXPECTED 
TO RELAX BY TOMORROW EVENING. 

ALOFT...SIGNS OF A REX BLOCK NOTED IN THE WRN PORTION OF THE 
DISCUSSION AREA WITH AN UPPER HIGH NEAR 28N134W N OF AN UPPER 
LOW NEAR 17N135W. NW FLOW AROUND A PRONOUNCED UPPER LOW OVER NRN 
ARIZONA IS ADVECTING VERY DRY/STABLE AIR INTO THE PAC WATERS OFF 
OF CENTRAL BAJA/E OF 130W. SWLY JET IS ADVECTING TROPICAL 
MOISTURE OVER THE ITCZ CONVECTION THROUGH THE NE PAC AND CENTRAL 
MEXICO. PRONOUNCED UPPER RIDGE AXIS FROM THE CARIBBEAN LIES OVER 
THE FAR NE PAC...WITH AXIS GENERALLY EXTENDING W ALONG 14N. 
UPPER DIFFLUENCE AROUND THIS RIDGE IS HELPING SUPPORT CONVECTION 
OVER THE ITCZ.

$$
WILLIS