000
AXPZ20 KNHC 272147
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU OCT 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS E TO W FROM 10N80W TO 08N97W TO  
12N116W WHERE LOW LEVEL WINDS INDICATE THE ITCZ AXIS BEGINS AND 
CONTINUES W TO NEAR 12N133W. A FEW SMALL CLUSTERS OF TSTMS ARE 
FLARING OVER THE PACIFIC ALONG THE COASTS OF PANAMA AND COSTA 
RICA. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 60 NM EITHER SIDE OF A LINE FROM 09N113W TO 10N124W TO 
14N128W TO 10N133W.

...DISCUSSION...

A LONG WAVE UPPER LEVEL TROUGH DISSECTS NORTH AMERICA FROM NE TO 
SW AND CONTINUES SW INTO THE DISCUSSION AREA FROM 32N105W TO 
31N126W THEN TURNS SW INTO AN UPPER CYCLONE CUTTING OFF NEAR 
26N136W AND ANOTHER CYCLONE AT 19N135W...WITH THE UPPER TROUGH 
CONTINUING S TO BASE OVER THE DEEP TROPICAL PACIFIC AT 06N131W. 
AN UPPER ANTICYCLONE IS OVER THE E PACIFIC NEAR 17N106W WITH AN 
UPPER RIDGE EXTENDING SW TO A CREST AT 10N122W. UPPER DIFFLUENCE 
E OF THE UPPER TROUGH AXIS IS ENHANCING CONVECTION ALONG THE 
ITCZ AND W EXTENSION OF THE MONSOON TROUGH AS PREVIOUSLY DESCRIBED. 
THE DEBRIS MOISTURE IS ADVECTED NE ALONG THE NW PERIPHERY OF THE 
RIDGE...ROUGHLY WITHIN 480 NM EITHER SIDE OF A LINE FROM 09N128W 
TO 27N122W.

VERY DRY UPPER AIR IS SPREADING SE THROUGH THE UPPER TROUGH 
ACROSS SOUTHERN CALIFORNIA AND THE N PORTIONS OF THE BAJA 
CALIFORNIA PENINSULA. DRY UPPER AIR IS ALSO NOTED S OF 23N E OF 
114W.

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS FROM 33N140W TO 
19N112W. 
 
GAP WINDS...A STRONG COLD FRONT WILL MOVE THROUGH THE SW GULF OF 
MEXICO ON FRI RESULTING IN A STRONG SURGE OF NORTHERLY WINDS TO 
FUNNEL THROUGH THE CHIVELA PASS AT 20 TO 25 KT LATE FRI 
AFTERNOON. THESE WINDS WILL INCREASE TO GALE FORCE LATE FRI 
NIGHT AND CONTINUE THROUGH MID DAY SAT BEFORE DIMINISHING BELOW 
GALE FORCE.

$$
NELSON