000
AXPZ20 KNHC 120250
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI AUG 12 2011

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
0245 UTC.

...ITCZ/MONSOON TROUGH...

A MONSOON TROUGH EXTENDS FROM THE BORDER OF PANAMA AND COLOMBIA 
AT 09N78W TO 10N90W TO 09N97W...THEN TURNS WNW THROUGH LOW PRES 
AT 14N118W TO 12N135W WHERE LOW LEVEL WINDS SUGGEST THE ITCZ 
AXIS BEGINS AND CONTINUES SW TO BEYOND 12N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM 
EITHER SIDE OF A LINE FROM 08N78W TO 06N89W...AND IN THE AREA 
BOUNDED BY 05N TO 12N BETWEEN 93W AND 98W...AND ALSO WITHIN 90 
NM OF 08N100W AND 09N113W...AND ALSO WITHIN 30 NM 15N120W.

...DISCUSSION...

A DEEP LAYERED CYCLONE IS W OF THE AREA AT 32N149W WITH A SERIES 
OF UPPER TROUGHS ROTATING CYCLONICALLY AROUND THE CENTER WITH 
THE EASTERNMOST TROUGH OVER THE AREA ALONG 32N137W TO 26N138W. 
DEBRIS MOISTURE IS SPREADING NE OVER THE DISCUSSION AREA N OF 
22N W OF 135W. THE UPPER TROUGH IS EXPECTED TO CONTINUE E TO 
ALONG 32N123W TO 23N130W LATE SAT.

A STATIONARY UPPER LEVEL ANTICYCLONE IS OVER THE BORDER OF NE 
OLD MEXICO AND THE TEXAS PANHANDLE AT 31N105W WITH AN UPPER 
RIDGE EXTENDING W TO NEAR 31N128W. THE ASSOCIATED UPPER 
DIFFLUENCE CONTINUES TO ENHANCE AFTERNOON CONVECTION OVER 
INTERIOR OLD MEXICO WITH THE DEBRIS MOISTURE SPREADING W OVER 
THE PACIFIC TO THE N OF 23N E OF 130W. DEBRIS MOISTURE IS ALSO 
ADVECTED N AROUND THE UPPER ANTICYCLONE OVER SOUTHERN CALIFORNIA 
AND SOUTHERN ARIZONA...THEN TURNING E ACROSS SOUTHERN NEW MEXICO 
AND NW TEXAS. THE ANTICYCLONE WILL MEANDER NEAR THE TEXAS 
PANHANDLE THROUGH SAT...WITH ITS ENVELOPE OF ANTICYCLONIC FLOW 
SPREADING S OVER THE DISCUSSION AREA S OF 20N E OF 120W.

AN E TO W UPPER TROUGH EXTENDS FROM NEAR THE SOUTHERN TIP OF THE 
BAJA CALIFORNIA PENINSULA WESTWARD TO AN UPPER CYCLONE AT 
22N125W...WITH THE TROUGH CONTINUING SW TO 09N140W. DRY UPPER 
AIR IS INDICATED WITHIN 120 NM EITHER SIDE OF A LINE FROM 
26N110W TO 22N119W TO 22N126W TO 12N140W...AND ALSO WITHIN 60 NM 
OF A LINE FROM 20N132W TO BEYOND 32N130W.    

AN UPPER ANTICYCLONE IS AT 17N119W WITH A RIDGE EXTENDING SW 
OVER THE MONSOON TROUGH AND ITCZ AXIS TO NEAR 13N127W. AN 
INVERTED UPPER TROUGH EXTENDS FROM 21N100W THROUGH AN UPPER 
CYCLONE AT 13N107W TO A BASE AT 08N109W AND IS PROGRESSING W 
WITH TIME. UPPER DIFFLUENCE BETWEEN THESE TWO UPPER FEATURES IS 
ENHANCING CONVECTION PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS 
MOISTURE IS OBSERVED FROM 04N TO 16N BETWEEN 110W AND 128W AND 
CONTINUES SW IN UPPER NE FLOW TO 05N137W. THE INVERTED TROUGH 
SHOULD ALONG 125W BY SAT. 

AN UPPER LEVEL ANTICYCLONE IS OVER THE GULF OF HONDURAS AT 
16N84W WITH ITS ENVELOPE OF ANTICYCLONIC FLOW COVERING THE 
TROPICS E OF 100W AND ENHANCING CONVECTION OVER THE PACIFIC S OF 
CENTRAL AMERICA. THE DEBRIS MOISTURE IS OBSERVED THE N OF 04N E 
OF 97W...AND ALONG 106N BETWEEN 97W AND 105W.

AT THE SURFACE...A RIDGE EXTENDS INTO THE DISCUSSION REGION FROM 
32N140W SE TO NEAR 20N110W. MIXED CROSS EQUATORIAL SE AND SW 
SWELL...RESULTING IN COMBINED SEAS OF 8 FT...IS LOCATED S OF 5N 
AND W OF 130W WHERE SE WINDS ARE AT 15 TO 20 KT...BUT EXPECTED 
TO DIMINISH FRI. THESE SOUTHERLY SWELLS HAVE REACHED ALONG 10N 
TO THE E OF 115W WITH COMBINED SEAS TO 11 FT IN MONSOONAL 15 KT 
SW FLOW. THESE SWELL SHOULD REACH ALONG 15N E OF 105W FRI AND E 
OF 100W ON SAT. 

$$
NELSON