000
AXPZ20 KNHC 160300
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE AUG 16 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.

...SPECIAL FEATURES...
TROPICAL DEPRESSION SIX E NEAR 12.2N133W 1007 MB AT 0300 UTC AUG 
16 MOVING W OR 270 DEG AT 8 KT. MAXIMUM SUSTAINED WINDS 30 KT 
WITH GUSTS TO 40 KT WITH HIGHEST SEAS OF 12 FT. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 240 NM OVER 
SW SEMICIRCLE OF CENTER. SIX E IS EXPECTED TO MOVE WEST AND 
INTENSIFY INTO A TROPICAL STORM DURING THE NEXT 24 HOURS AS IT 
MOVES INTO A MORE FAVORABLE ENVIRONMENT. REFER TO 
FORECAST ADVISORIES ISSUED UNDER WMO HEADER WTPZ21 KNHC AND 
AWIPS HEADER MIATCMEP1 FOR FURTHER DETAILS.

A LOW PRES IS EMBEDDED IN THE MONSOON TROUGH GYRE NEAR 13N96W 
AND IS ESTIMATED AT 1007 MB. CYCLONIC WINDS OF 20 TO 25 KT ARE 
WITHIN 270 NM NE AND WITHIN 360 NM SW SEMICIRCLES WITH SEAS 8 TO 
11 FT IN MIXED SWELL. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS OBSERVED WITHIN 330 NM NW AND WITHIN 180 NM SE 
SEMICIRCLES OF CENTER. THE LOW IS FORECAST TO MOVE NW OVER THE 
NEXT TWO DAYS...AND MAY DEVELOP INTO A TROPICAL CYCLONE.

...TROPICAL LOW...
A LOW PRES IS EMBEDDED IN THE MONSOON TROUGH GYRE NEAR 12N110W 
AND IS ESTIMATED AT 1009 MB. CYCLONIC WINDS OF 15 TO 20 KT ARE 
WITHIN 180 NM N AND WITHIN 420 NM S SEMICIRCLES WITH SEAS 8 TO 
10 FT IN MIXED SWELL. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS OBSERVED WITHIN 330 NM OVER THE SEMICIRCLE OF 
CENTER. THE LOW IS FORECAST TO MOVE W OVER THE NEXT TWO DAYS.  

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM COSTA RICA AT 09N85W TO THE LOW 
PRES AT 13N96W...THEN CONTINUES W THROUGH THE LOW PRES AT 
12N110W TO TROPICAL DEPRESSION SIX E AT 12N132W. EXCEPT AS 
ASSOCIATED WITH THE LOW PRESSURE AREAS PREVIOUSLY MENTIONED... 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED NE OF 
LINE FROM 02N78W TO 07N90W...AND WITHIN 60 NM EITHER SIDE OF A 
LINE FROM 10N97W TO 10N103W AND ALSO FROM 06N TO 12N BETWEEN 
112W AND 118W.

...DISCUSSION...

AN UPPER TROUGH IS SWINGING SE OVER THE NW PORTION FROM 32N125W 
TO 22N137W THEN S INTO AN UPPER CYCLONE AT 17N140W. DRY UPPER 
AIR IS NOTED TO THE N OF 22N W OF 127W. A QUASI STATIONARY UPPER 
ANTICYCLONE IS OVER THE TEXAS PANHANDLE WITH A RIDGE SW TO 
28N122W. UPPER DIFFLUENCE HAS ENHANCED CONVECTION OVER NW OLD 
MEXICO AND OVER THE NORTHERN GULF OF CALIFORNIA WITH THE DEBRIS 
MOISTURE SPREADING W OVER THE PACIFIC E OF A LINE FROM 20N128W 
TO SW ARIZONA. DENSE UPPER MOISTURE ALSO ROTATES AROUND THE 
ANTICYCLONE OVER SE ARIZONA AND SOUTHERN NEW MEXICO EVENTUALLY 
SPILLING SE OVER W TEXAS. THE ANTICYCLONE IS EXPECTED TO MEANDER 
NEAR THE TEXAS PANHANDLE THROUGH MID WEEK BLOCKING THE EASTWARD 
PROGRESS OF A SERIES OF UPPER TROUGHS THAT WILL STALL OVER THE 
NW PORTION. 

A SERIES OF INVERTED UPPER TROUGHS ARE SHIFTING W ACROSS THE 
AREA ALONG THE SOUTHERN PERIPHERY OF THE RIDGE. ONE EXTENDS FROM 
22N117W TO 12N124W AND THE SECOND FROM 20N95W TO 05N102W. A 
THIRD TROUGH IS ALONG 80W. UPPER DIFFLUENCE TO THE W OF THESE 
UPPER TROUGHS IS SUPPORTING THE AREAS OF ENHANCED CONVECTION 
PREVIOUSLY MENTIONED...WITH THE RESULTANT DEBRIS MOISTURE 
COVERING THE DISCUSSION AREA FROM 03N TO 20N E OF 124W.
 
AT THE SURFACE...A WEAK COLD FRONT EXTENDS FROM 32N133W TO 
30N140W. A BROAD RIDGE DOMINATES THE LOW LEVELS N OF 15N W OF 
105W. SOUTHERLY CROSS EQUATORIAL SWELL...RESULTING IN COMBINED 
SEAS OF 8 FT...IS LOCATED S OF 15N BETWEEN 90W AND 110W.

$$
NELSON