000
AXPZ20 KNHC 130322
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE JUL 13 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...SPECIAL FEATURE...

.SURFACE LOW PRESSURE NEAR 12.5N 97.5W AND ESTIMATED AT 1007 
MB...AND IS MOVING JUST N OF DUE W AT ABOUT 10 KT. THE AREA 
SURROUNDING THE LOW HAS BEEN VOID OF SURFACE OBSERVATIONS FOR 
THE PAST 9 HOURS BUT EXPECT NORTHERLY WINDS AT 15 TO 20 KT 
WITHIN 180 NM OF CENTER OVER THE NW SEMICIRCLE WITH MAX SEAS TO 
7 FT. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 120 NM OVER THE NW SEMICIRCLE. THIS LOW PRES MAY DEVELOP 
INTO A TROPICAL CYCLONE AS IT MOVES TO A POSITION NEAR 13N 
101.5W AT 0000 UTC WED...AND NEAR 14.5N 105W AT 0000 UTC THU.

...TROPICAL LOW...
 
.A TROPICAL LOW PRESSURE WAS CENTERED NEAR 11N130W 1012 MB THIS 
AFTERNOON BUT SEEMS TO HAVE WEAKENED TO A TROUGH EXTENDING FROM 
10N132W TO 15N130W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS OBSERVED WITHIN 150 NM OF 13N 128W. CURRENTLY 
WINDS ARE ENHANCED TO 15 TO 20 KT WITHIN ABOUT 240 NM OVER THE 
NE SEMICIRCLE WITH MAX SEAS OF 8 FT. THE TROUGH IS EXPECTED TO 
MEANDER IN THIS SAME FOR A COUPLE OF DAYS.

...TROPICAL WAVES...

A PAIR OF TROPICAL WAVES ARE MOVING THROUGH THE AREA N OF 08N 
BETWEEN 85W AND 100W. UPPER DIFFLUENCE IS ENHANCING SCATTERED 
STRONG MODERATE ISOLATED STRONG OVER THE AREA N OF 06N BETWEEN 
80W AND 105W AS DESCRIBED IN MORE DETAIL ELSEWHERE IN THIS 
DISCUSSION. 

...ITCZ...

THE AXIS EXTENDS ALONG 10N85W TO 07N104W TO 10N125W TO 07N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 90 
NM OF 08N87W...WITHIN 60 NM OF 08N93W...AND ALSO WITHIN 180 NM 
OF 07N104W. ISOLATED MODERATE CONVECTION CONTINUE TO FLARE ALONG 
THE ITCZ WITHIN 15 NM EITHER SIDE OF A LINE FROM 10N125W TO 
06N140W.

...DISCUSSION...

AN UPPER CYCLONE IS NEAR 32N127W WITH A SERIES OF UPPER TROUGHS 
EXTENDING S INTO THE AREA N OF 13N BETWEEN 127W AND 135W. AT THE 
LOW LEVELS A TROUGH EXTENDS FROM 30N132W TO 15N130W AND IS 
MOVING E FOLLOWED BY NE WINDS AND SEAS TO 8 FT IN NE SWELL. 
UPPER LEVEL DIFFLUENCE IS NOTED FROM 05N TO 15N BETWEEN 122W AND 
140W AND ENHANCING CONVECTION AS PREVIOUSLY DESCRIBED. THE 
DEBRIS MOISTURE REMAINS IN ROUGHLY THE SAME AREA. OTHERWISE THE 
UPPER LEVELS ARE VERY DRY W OF 122W.
    
AN UPPER LEVEL ANTICYCLONE IS NEAR 31N99W WITH AN UPPER LEVEL 
RIDGE EXTENDING WSW TO A CREST AT 26N122W. A SECOND UPPER 
ANTICYCLONE IS CENTERED AT 22N103W WITH ITS ENVELOPE OF 
ANTICYCLONIC FLOW COVERING THE AREA S OF 22N E OF 114W. AN 
EMBEDDED UPPER TROUGH EXTENDS FROM 16N118W TO 26N118W AND 
PROGRESSING SLOWLY W WITH TIME. UPPER DEBRIS MOISTURE IS NOTED 
FROM 15N TO 27N BETWEEN 113W AND 122W. THE UPPER RIDGE IS 
ENHANCING CONVECTION OVER CENTRAL AMERICA AND OVER THE ITCZ E OF 
106W...WITH DENSE UPPER MOISTURE INDICATED S OF 20N E OF 111W.

S TO SW WINDS PERSIST IN THE 15 TO 20 KT RANGE OVER THE TROPICAL 
WATERS FROM 04N TO 10N BETWEEN 88W AND 107W WITH SEAS TO 8 FT IN 
S SWELL.

$$
NELSON