000
AXPZ20 KNHC 220310
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON AUG 22 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 
0215 UTC.

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM 10N85W TO INLAND OVER S MEXICO NEAR 
17N97W TO 12N115W. IT THEN RESUMES FROM 14N123W TO BEYOND THE 
AREA AT 10N140W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 
14N-16N BETWEEN 110W-112W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION IS WITHIN 90 NM S OF MONSOON TROUGH BETWEEN 124W-128W 
AND N OF 14N BETWEEN 95W-101W.

...DISCUSSION...

W OF 120W...

AN UPPER LEVEL LOW IS CENTERED NEAR 32N129 WITH AN UPPER TROUGH 
EXTENDING S TO NEAR 25N132W. THIS UPPER LOW IS FORECAST TO DROP 
NEAR 29N128W BY MON EVENING WHILE BECOMING CUT-OFF FROM THE 
NORTHERN STREAM JET STREAM BRANCH. ELSEWHERE AN UPPER LEVEL 
ANTICYCLONE IS ANCHORED NEAR 19N141W WITH A RIDGE EXTENDING 
EASTWARD TO 125W. A WEAK NARROW UPPER TROUGH IS ALONG 123W WHICH 
WILL MERGE WITH THE LARGER UPPER TROUGH ABOVE. AT THE 
SURFACE...THE REMNANTS OF FORMER TROPICAL DEPRESSION GREG IS 
BENEATH THIS TROUGH CENTERED NEAR 20N124W 1008 MB LOW DRIFTING 
WESTWARD. IT IS MARKED BY A LARGE SWIRL OF LOW AND MID LEVEL 
CLOUDS WITH ISOLATED SHOWERS WITHIN 240 NM IN THE NW QUADRANT.  
THE LOW IS FORECAST TO WEAKEN FURTHER THROUGH THE NEXT 48 HOURS 
AS IT REACHES NEAR 19N129W.

SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE SUBSIDENCE COVERING 
MUCH OF THIS PORTION OF THE AREA INCLUDING THE UPPER ATMOSPHERE 
FROM 15 TO 28N BETWEEN 123W AND 140W. THIS IS ALLOWING FOR THE 
ATMOSPHERE TO REMAIN RATHER DRY AND STABLE INHIBITING DEEP 
CONVECTION ACROSS THE AREA. ELSEWHERE AT THE SURFACE...A WEAK 
1021 MB HIGH IS N OF THE AREA NEAR 34N137W WITH A RIDGE SE TO 
24N116W. THIS IS INCREASING THE WINDS TO THE NW OF THE REMNANTS 
OF GREG. 

E OF 120W...A LARGE AND NEARLY STATIONARY ANTICYCLONE ANCHORED 
OVER CENTRAL TEXAS EXTENDING A RIDGE SW TO OVER CENTRAL BAJA 
CALIFORNIA TO NEAR 26N112W. A SMALL UPPER LEVEL LOW IS OVER 
CENTRAL MEXICO AT 24N106W. THE FLOW PATTERN TO SW OF THE UPPER 
LEVEL LOW OVER MEXICO IS RATHER DIFFLUENT BETWEEN 104W-115W. SW 
20 KT WINDS WILL CONTINUE TO FEED INTO THE MONSOON TROUGH IN THE 
VICINITY OF 106W TO 108W OVER THE NEXT 48 HOURS WITH SEAS TO 9 
FT. 

ALSO WITH RESPECT TO MARINE ISSUES...LONG PERIOD CROSS-EQUATORIAL
SWELLS RESULTING IN SEAS TO 9 FT WILL BE CONFINED TO S OF 8N
BETWEEN 100W-120W. ACCORDING TO WAVEWATCH MODEL GUIDANCE THESE
SWELLS SHOULD LAST THROUGH THE NEXT 48 HOURS.

$$
PAW