000
AXPZ20 KNHC 280918
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON JUL 28 2008

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.

...TROPICAL WAVES... 

TROPICAL WAVE LIES ALONG 84W N OF 05N...MOVING W 15 KT.  A BURST 
OF SCATTERED STRONG CONVECTION HAS ERUPTED WITHIN 90-120 NM OF 
THE COAST OF COSTA RICA AND THE WAVE AXIS FROM 08N TO 10N. 
ADDITIONAL CONVECTION ASSOCIATED WITH THE WAVE IS IN THE FORM OF 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION MAINLY WITHIN 
120 NM S OF THE INTERSECTION OF THE WAVE AXIS AND THE ITCZ. THIS 
CONVECTION IS SUPPORTED BY DIFFLUENCE ALOFT BETWEEN AN 
ANTICYCLONE OVER HONDURAS/NICARAGUA AND ANOTHER BROAD UPPER 
LEVEL ANTICYCLONIC CIRCULATION OVER NW SOUTH AMERICA. 

TROPICAL WAVE ORIENTED SSW-NNE FROM 07N112W TO 19N110W MOVING W 
AT 10 KT. THE WAVE IS CURRENTLY UNDER A REGION OF BROAD UPPER 
LEVEL DIFFLUENCE ON THE E SIDE OF AN UPPER LEVEL CYCLONE NEAR 
21N111W ROLLING WWD TO THE NORTH OF THE WAVE. IN ADDITION THE 
WAVE IS SITUATED WITHIN AN AREA POSSESSING DEEP SUBTROPICAL 
MOISTURE. THIS SHOULD HELP THE WAVE MAINTAIN SOME CONVECTION 
OVER THE NEXT DAY OR SO...BUT AS IT MOVES W...EXPECT THE UPPER 
LEVEL DIFFLUENCE TO DIMINISH AND THE SYSTEM TO MOVE OVER COLDER 
WATER IN THE WAKE OF GENEVIEVE.
  
...ITCZ...
ITCZ AXIS LIES ALONG 08N78W TO 06N88W TO 12N110W TO 07N140W. 
SCATTERED MODERATE TO STRONG WITHIN 90-120 NM OF THE AXIS 
BETWEEN 92W AND 99W...AND FROM 03N TO 07N E OF 81W TO THE COAST 
OF COLOMBIA. SCATTERED MODERATE ISOLATED STRONG WITHIN 120 NM S 
OF THE AXIS BETWEEN 81W AND 90W. SCATTERED MODERATE WITHIN 60-90 
NM OF THE AXIS BETWEEN 113W AND 117W...AND W OF 133W.

...DISCUSSION...
A FORMIDABLE UPPER TO MID LEVEL RIDGE CENTERED OVER NORTHERN 
MEXICO AND THE SW CONUS IS EXPECTED TO SHIFT WESTWARD ALONG 30N 
THE NEXT FEW DAYS AND BEGIN TO BREAK DOWN THE TROUGHING THAT HAS 
PERSISTED ALONG 135W THE LAST SEVERAL DAYS. AS A RESULT...MUCH 
OF THE SENSIBLE WEATHER AWAY FROM THE NORTH AMERICAN CONTINENT 
IS EXPECTED TO REMAIN S OF 20N AND SHOULD PRIMARILY FOCUS ON THE 
TROPICAL WAVES PASSING THROUGH THE REGION.  

A 1010 MB SURFACE LOW EMBEDDED IN THE ITCZ NEAR 06N94W IS 
FORECAST TO MOVE W AT 10 KT OVER THE NEXT DAY OR SO. GLOBAL 
MODELS DO NOT FAVOR SIGNIFICANT DEVELOPMENT. A SMALL AREA OF 20 
KT WINDS IS FORECAST TO ACCOMPANY THIS FEATURE AS IT TREKS WWD 
OVER THE E PACIFIC. SCATTERED MODERATE TO STRONG CONVECTION IS
ASSOCIATED WITH THE LOW AND THE ITCZ IN AN AREA BETWEEN 92W AND
99W. 

THE DEEP EASTERLY FLOW ACROSS THE CARIBBEAN THROUGH THE GULF OF 
PAPAGAYO HAS WEAKENED WITH A SUBSEQUENT 0246 UTC ASCAT PASS FROM 
SHOWING AN ISOLATED AREA OF 20 KT WINDS NEAR THE GULF OF 
PAPAGAYO. THESE WINDS SHOULD DIMINISH TO LESS THAN 20 KT WITHIN 
THE NEXT 12-18 HOURS.  
 
$$
COBB