000
AXPZ20 KNHC 091540
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU JUL 09 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS N OF 8N TO THE COAST OF MEXICO AT THE GULF OF 
TEHUANTEPEC ALONG 95W MOVING W 10-15 KT. THE WAVE AXIS EXTENDS 
NWD INTO THE BAY OF CAMPECHE. A WELL DEFINED INVERTED-V PATTERN 
IS NOTED ON VIS SATELLITE IMAGERY WITH SCATTERED SHOWERS AND 
ISOLATED TSTMS WITHIN ABOUT 200 NM EITHER SIDE OF AXIS. A 
CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION EMBEDDED IN 
THE ITCZ IS NEAR THE SOUTH END OF THE WAVE AXIS WHERE SOME 
CYCLONIC TURNING IS ALSO NOTED.

AN ACTIVE TROPICAL WAVE IS ALONG 108W/109W FROM 5N-13N WITH AN 
EMBEDDED 1009 MB LOW PRES NEAR 10N. A CLUSTER OF MODERATE TO 
STRONG CONVECTION IS WITHIN 90 NM OF LOW CENTER. DEVELOPMENT OF 
THIS SYSTEM IS EXPECTED TO BE SLOW TO OCCUR AS IT MOVES WESTWARD 
NEAR 10 KT OVER THE NEXT COUPLE OF DAYS. SOME BANDING-LIKE 
FEATURES ARE ALSO NOTED PARTICULARLY TO THE SE. 

THE THIRD TROPICAL WAVE IS ALONG 124W/125W FROM 5N-13N. ISOLATED 
MODERATE CONVECTION IS NEAR THE INTERSECTION OF THE WAVE WITH 
THE ITCZ AXIS.    

...ITCZ...
THE ITCZ AXIS IS ALONG 08N78W TO 10N100W TO 07N120W TO 10N140W. 
SCATTERED MODERATE WITHIN 300 NM S OF AXIS E OF 86W. SCATTERED 
MODERATE TO ISOLATED STRONG WITHIN 250 NM S OF AXIS BETWEEN 96W 
AND 101W. SIMILAR CONVECTION IS FOUND FROM 04N TO 11N BETWEEN 
104W AND 116W.   

...DISCUSSION...
AN UPPER-LEVEL ANTICYCLONIC CIRCULATION REMAINS CENTERED OVER 
NORTHERN MEXICO NEAR 30N105W WITH A RIDGE EXTENDING WWD OVER THE 
BAJA CALIFORNIA PENINSULA AND THE NE PORTION OF THE FORECAST 
AREA MAINLY N OF 22N E OF 120W. THE REMNANTS OF BLANCA CONTINUE 
TO MOVE AROUND THE PERIPHERY OF THIS RIDGE. AN UPPER-LEVEL 
TROUGH HAS ENTERED THE NW PORTION OF THE DISCUSSION AREA.
ACCORDING TO THE COMPUTER MODELS...THE UPPER-LEVEL RIDGE IS 
EXPECTED TO SHIFT NEWD TOWARDS THE SOUTHERN PLAINS OF U.S. 
DURING THE NEXT FEW DAYS AS THE UPPER-LEVEL TROUGH AMPLIFIES 
OVER THE W PORTION OF THE DISCUSSION AREA. AT THE SURFACE...THE 
RIDGE OVER NW WATERS WILL CONTINUE TO WEAKEN IN RESPONSE TO THE 
INCREASED TROUGHING ALOFT. AS A RESULT...THE TRADE WINDS HAS 
DIMINISHED BELOW 20 KT. 

THE REMNANT LOW OF BLANCA...1009 MB..IS NEAR 22N123W MOVING NW 
10 KT. A NEW BURST OF DEEP CONVECTION IS CURRENTLY OCCURRING ON 
THE NORTHERN SIDE OF THE LOW CENTER. WINDS IN THE 20-25 KT RANGE 
AND SEAS UP TO 9 FT REMAIN WITH THE LOW PARTICULARLY OVER THE NW 
SEMICIRCLE DUE TO THE PRES GRADIENT BETWEEN THE LOW ITSELF AND 
THE SURFACE RIDGE COVERING THE NW WATERS. THESE CONDITIONS ARE 
EXPECTED TO PERSIST DURING THE NEXT 48 HOURS.

NE WINDS OF 20 KT ARE EXPECTED ACROSS THE GULF OF PAPAGAYO W OF 
88W IN ABOUT 24 HOURS THANKS TO THE STRONG TRADE WINDS ACROSS 
THE CARIBBEAN SEA. 

LARGE SWELLS FROM THE SOUTHERN HEMISPHERE ARE SUBSIDING AND ARE 
EXPECTED TO BE BELOW 8 FT LATER TODAY.

$$
GR