000
AXPZ20 KNHC 122209
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON JUL 12 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...SPECIAL FEATURE...

.BROAD LOW PRESSURE IS ANALYZED AS A SURFACE LOW NEAR 12.5N 
96.5W AND ESTIMATED AT 1007 MB...AND IS MOVING W AT ABOUT 10 KT. 
CURRENTLY NORTHERLY WINDS ARE ENHANCED TO 15 TO 20 KT WITHIN 240 
NM OF CENTER OVER THE NW QUADRANT WITH MAX SEAS TO 8 FT. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 
300 NM OVER THE NW SEMICIRCLE. THIS LOW PRES MAY DEVELOP INTO A 
TROPICAL CYCLONE AS IT MOVES TO A POSITION NEAR 13.5N 100.5W AT 
1800 UTC TUE...AND NEAR 14.5N 104.5W AT 1800 UTC WED.

...TROPICAL LOW...
 
.A TROPICAL LOW PRESSURE IS CENTERED NEAR 11N130W 1012 MB THIS 
AFTERNOON AND IS PART OF A LARGE AREA OF LOW PRESSURE BOUNDED BY 
09N TO 15N BETWEEN 125W AND 135W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS OBSERVED WITHIN 30 NM OF 12.5N 128.5W. 
CURRENTLY WINDS ARE ENHANCED TO 15 TO 20 KT WITHIN ABOUT 240 NM 
OVER THE NE SEMICIRCLE WITH MAX SEAS OF 8 FT. THIS LOW PRESSURE 
IS EXPECTED TO FILL TONIGHT WITH A SURFACE TROUGH EXTENDING FROM 
10N131W TO 16N124W LATE TUE...AND FROM 10N131W TO 14N127W LATE 
WED...WITH A NE TO E WIND SHIFT AT 15 TO 20 KT ALONG THE TROUGH 
AXIS THROUGHOUT THE PERIOD.

...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 104W AS DESCRIBED IN MORE DETAIL ELSEWHERE IN THIS 
DISCUSSION. 

...ITCZ...

THE AXIS EXTENDS ALONG 11N85W TO 11N97W TO 08N104W TO 09N126W TO 
07N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED  
WITHIN 90 NM OF 07N86.5W...WITHIN 60 NM OF 08.5N93W...AND ALSO 
WITHIN 150 NM OF 06.5N101W. ISOLATED MODERATE TO STRONG 
CONVECTION IS FLARING WITHIN 150 NM OF 09.5N125W AND 08N130W AND 
WITHIN 15 NM OF LINE 07N135W TO 07N138W.

...DISCUSSION...

AN UPPER CYCLONE IS NEAR 32N126W WITH A SERIES OF UPPER TROUGHS 
EXTENDING S INTO THE AREA N OF 13N BETWEEN 125W AND 135W. AT THE 
LOW LEVELS A TROUGH EXTENDS FROM 30N127W TO 26N140W AND IS 
MOVING E FOLLOWED BY NE WINDS AND SEAS TO 9 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 31N98W WITH AN UPPER LEVEL 
RIDGE EXTENDING WSW TO A CREST AT 26N123W. A SECOND UPPER 
ANTICYCLONE IS CENTERED AT 17N91W WITH ITS ENVELOPE OF 
ANTICYCLONIC FLOW COVERING THE AREA S OF 22N E OF 112W. AN 
EMBEDDED UPPER TROUGH EXTENDS FROM 16N118W TO 27N117W AND 
PROGRESSING SLOWLY W WITH TIME. UPPER DEBRIS MOISTURE IS NOTED 
FROM 14N 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 108W.

S TO SW WINDS PERSIST IN THE 15 TO 20 KT RANGE OVER THE TROPICAL 
WATERS FROM 04N TO 10N BETWEEN 90W AND 108W WITH SEAS TO 8 FT IN 
S SWELL.

$$
NELSON