000
AXPZ20 KNHC 230917
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU AUG 23 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0800 UTC.

...TROPICAL WAVE...

A TROPICAL WAVE LIES ALONG 96W N OF 10N AND IS MOVING W AT 10 TO 
15 KT. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS 
FOUND NEAR WHERE THE WAVE COMES CLOSEST TO THE MONSOON TROUGH 
FROM 06N TO 11N BETWEEN 90W AND 96W.

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

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 08N78W TO 13N103W TO 
12N110W TO 1010 MB LOW PRES NEAR 11N137W. ITCZ AXIS WAS ANALYZED 
FROM 11N138W TO 09N140W. ISOLATED MODERATE CONVECTION WAS WITHIN 
60 NM N AND 210 NM S OF THE AXIS BETWEEN 108W AND 134W.

...DISCUSSION...

A BROAD ANTICYCLONE ALOFT OVER THE NORTHERN GULF OF CALIFORNIA 
NEAR 29N113W EXTENDS RIDGE AXES SOUTHWESTWARD THROUGH 26N130W TO 
ANOTHER ANTICYCLONE NEAR 29N113W AS WELL AS SOUTHWARD TO 
17N114W. WATER VAPOR IMAGERY SHOWS DRY CONDITIONS ALOFT AND 
IMPLIED SUBSIDENCE N OF 29N W OF THE GULF OF CALIFORNIA AND N OF 
15N W OF 133W. BROADLY DIFFLUENT 25 TO 30 KT E-NE FLOW S OF THE 
ANTICYCLONE LIES OVER THE SURFACE LOW PRES SYSTEM NEAR 20N109W. 
THIS 1010 MB LOW PRES SYSTEM HAD SCATTERED MODERATE CONVECTION 
SKEWED BETWEEN 75 NM AND 210 NM OF ITS SW QUADRANT. THE 1504 UTC 
ASCAT PASS SHOWS A CLOSED CIRCULATION AROUND THE CENTER BUT 
WINDS REMAIN A MODERATE BREEZE OR LESS. THIS LOW IS FORECAST TO 
GRADUALLY OPEN UP INTO A TROUGH OVER THE NEXT 48 HOURS AS THE 
SHEAR ALOFT TAKES ITS TOLL ON THE SYSTEM. 

THE SUBTROPICAL RIDGE OVER THE FORECAST AREA IS WEAK...STEMMING 
FROM 1030 MB HIGH PRES WELL TO THE NW OF THE FORECAST AREA NEAR 
47N146W. THE COMPROMISED SUBTROPICAL RIDGE HAS YIELDED TRADE 
WINDS ONLY AS STRONG AS A MODERATE BREEZE OVER THE FORECAST 
AREA...WITH A FRESH BREEZE FOUND ON THE N SIDE OF 1010 MB LOW 
PRES NEAR 11N137W WHERE THE GRADIENT IS TIGHTEST. THIS 
PERSISTENT LOW PRES SYSTEM CONTINUES TO SUPPORT CONVECTION WITH 
SCATTERED MODERATE CONVECTION FOUND WITHIN 60 NM NE QUADRANT AND 
90 NM W SEMICIRCLE OF THE LOW. THIS LOW IS FORECAST TO OPEN UP 
OVER THE NEXT DAY OR SO AS IT MOVES W OF THE FORECAST AREA.

CROSS-EQUATORIAL SE TO S SWELL TO 8 FT WILL LIE OVER THE 
FORECAST AREA S OF 06N W OF 120W INTO FRI AND THEN SHIFT 
EASTWARD TO BETWEEN THE GALAPAGOS ISLANDS AND 120W INTO SAT.

$$
SCHAUER