000
AXPZ20 KNHC 212151
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE AUG 21 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2045 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM 09N84W TO 05N95W TO 1010 MB LOW PRES 
NEAR 13N109W TO 10N122W. ITCZ AXIS IS FROM 10N122W TO 1010 MB 
LOW PRES NEAR 12N130W TO 10N140W. SCATTERED MODERATE FROM 05N TO 
10N BETWEEN 83W AND 89W. SCATTERED MODERATE WITHIN 60 NM S OF 
TROUGH BETWEEN 110W AND 112W. ISOLATED MODERATE FROM 06N TO 10N 
BETWEEN 122W AND 130W.

...DISCUSSION...

THE ANTICYCLONE ALOFT OVER NW MEXICO NEAR 29N111W EXTENDS A 
RIDGE SOUTHEASTWARD ALONG THE COAST OF MAINLAND MEXICO TO THE 
GULF OF TEHUANTEPEC. DIFFLUENT CONDITIONS ASSOCIATED WITH THIS 
RIDGE ARE ENHANCING THE CONVECTION AROUND A 1011 LOW PRES 
LOCATED NEAR 20N108W. THIS LOW PRES IS FORECAST BY THE GFS 
COMPUTER MODEL TO REMAIN NEARLY STATIONARY OVER THE NEXT 24 
HOURS. THE 1634 UTC ASCAT PASS SHOWS THE CYCLONIC CIRCULATION 
ASSOCIATED WITH THIS LOW CENTER BUT WINDS REMAIN IN THE 10 TO 15 
KT RANGE. ANOTHER ANTICYCLONIC CIRCULATION CENTERED NEAR 22N127W 
HAS A RIDGE EXTENDING SOUTHWESTWARD TO BEYOND 15N14OW. IN 
BETWEEN...THERE IS AN INVERTED TROUGH ALONG 123W FROM 15N TO 
24N. STRONG SUBSIDENCE AND IMPLIED DRY AIR MASS COVERS ROUGHLY 
THE AREA N OF 10N W OF 125W. NE WIND FLOW ALOFT DOMINATES MOST 
OF THE AREA E OF 110W.

ELSEWHERE AT LOW LEVELS...A 1022 MB HIGH IS SITUATED NEAR 
29N144W. A RIDGE EXTENDS FROM THIS HIGH TO NEAR 20N122W. THIS 
SYSTEM WILL MOVE LITTLE DURING THE NEXT 24 HOURS...THEN WILL BE 
ABSORBED BY A STRONGER HIGH PRES LOCATED WELL NW OF THE FORECAST 
AREA. MODERATE TRADE WINDS ARE NOTED AROUND THE SOUTHERN 
PERIPHERY OF THE RIDGE PER THE 1816 UTC ASCAT PASS.
 
THE REMNANTS OF HECTOR ARE STILL SEEN ON VISIBLE SATELLITE 
PICTURE NEAR 22N115W. A WELL DEFINED SWIRL OF LOW CLOUDS IS 
OBSERVED NEAR 12N130.5W. ANOTHER WEAK LOW PRES IS ALONG THE 
MONSOON TROUGH NEAR 13N109W. ALL THESE WEAK LOWS ARE FORECAST TO 
DISSIPATE IN ABOUT 24 HOURS. 

CROSS-EQUATORIAL SE TO S SWELL TO 8 FT WILL LIE OVER THE SOUTH 
WATERS MAINLY S OF 05N BETWEEN 115W AND 130W OVER THE NEXT FEW 
DAYS. THE 1818 ASCAT PASS SHOWED AN AREA OF SE WINDS OF 20 TO 25 
KT S OF 06N BETWEEN 120W AND 128W.   

$$
GR