000
AXPZ20 KNHC 090337
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JAN 09 2013

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 
0330 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 05N77W TO 10N85W TO 06N90W THEN ITCZ 
CONTINUES THROUGH 06N110W TO 09N140W. NO SIGNIFICANT CONVECTION. 

...DISCUSSION...
HIGHLY AMPLIFIED PATTERN IN PLACE OVER THE DISCUSSION AREA WHICH 
FEATURES A CUT-OFF LOW SPINNING OVER N-CENTRAL MEXICO NEAR 
28N106W. THE UPPER LOW IS CURRENTLY STATIONARY AND WAS EMBEDDED 
WITHIN A LARGER LONGWAVE DEEP TROUGH WHICH COVERS THE EAST 
PACIFIC BETWEEN 100W AND 120W. AXIS OF SUBTROPICAL JET-STREAM 
WITH MAXIMUM WINDS OF 110-130 KT ROUNDS THE BASE OF THE LOW AND 
TROUGH SOUTH OF BAJA CALIFORNIA AND TURNS NNE ACROSS EASTERN 
MAINLAND MEXICO INTO CENTRAL TEXAS. NEGATIVELY TILTED RIDGE 
EXTENDS FROM 07N123W TO BEYOND 30N132W WITH A COUPLED NEGATIVELY 
TILTED TROUGH EXTENDING FROM JUST E OF THE HAWAIIAN ISLANDS TO 
08N135W. STRONGLY DIFFLUENT UPPER FLOW WAS ENHANCING 
THUNDERSTORMS ALONG AND WELL N OF THE ITCZ W OF 120W AND FANNING 
THE MID TO UPPER LEVEL MOISTURE NORTHEAST ACROSS THE AREA N OF 
10N W OF 120W...EXCEPT ACROSS THE FAR NE CORNER WHERE STRONG 
SUBSIDENCE WAS OCCURRING ON THE BACKSIDE OF THE TROUGH OVER THE 
EAST PACIFIC. AN UPPER-LEVEL TROUGH OVER THE WESTERN CARIBBEAN 
AND NORTHERN CENTRAL AMERICA EXTENDS INTO THE EPAC WATERS TO 
NEAR 5N90W. 

FRESH TO STRONG N-NE TRADES WINDS ASSOCIATED WITH A 1026 MB 
SUBTROPICAL HIGH CENTERED NEAR 34N135W PREVAIL ACROSS MOST OF 
THE AREA N OF THE ITCZ W OF 117W. AN 1818 UTC ASCAT AND A LATER 
2036 UTC OSCAT PASS CONFIRMED THE PRESENCE OF THESE WINDS WITH 
AN AREA OF STEADY 25...AND LOCALLY 30 KT WINDS FROM 10N TO 14N W 
OF 135W. AN ADDITIONAL PATCH OF FRESH NW TO N WINDS ARE ALSO 
NOTED JUST OFF THE BAJA CALIFORNIA PENINSULA ROUGHLY FROM 23N TO 
27N AND E OF 118W. THE HIGH PRES HAS WEAKENED FROM EARLIER TODAY 
AND WILL CONTINUE TO WEAKEN ON WED AS A COLD FRONT APPROACHES 
THE WEST COAST OF THE CONUS. EVEN STRONGER HIGH PRES WILL 
DEVELOP BEHIND THE COLD FRONT NEAR 40N142W BY THU MORNING. THIS 
WILL CREATE A VERY TIGHT PRES GRADIENT BETWEEN THE HIGH AND 
LOWER PRESSURE ALONG THE ITCZ...RESULTING IN A BROAD AREA OF 20 
TO 30 KT NE-E WINDS AND BUILDING SEAS 8 TO 14 FT W OF 120W THU 
THROUGH SAT. THIS VERY STRONG HIGH PRES...1040-1042 MB...WILL 
ALSO INDUCE GALE FORCE NW WINDS ALONG THE CALIFORNIA COAST THU 
AFTERNOON THROUGH EARLY SAT...GENERATING LARGE N-NW SWELL THAT 
WILL SPREAD SOUTHWARD W OF THE BAJA CALIFORNIA PENINSULA...WITH 
SEAS BUILDING TO 13-15 FT N OF 27N BY FRI.

GAP WINDS...
THE GAP WIND EVENT IN THE GULF OF TEHUANTEPEC HAS ENDED. AN 
1854 UTC OSCAT PASS RECEIVED SINCE THE PREVIOUS ISSUANCE OF THIS 
PRODUCT INDICATED THAT WINDS HAVE DROPPED BELOW 20 KT.   

FRESH WINDS EXPECTED TO PULSE DOWNSTREAM FROM THE GULF OF 
PAPAGAYO THROUGH THU AS WESTERN CARIBBEAN TRADES REMAIN NEAR 
GALE FORCE. STRONGEST WINDS WILL OCCUR LATE AT NIGHT AND EARLY 
MORNING HOURS WITH THE ASSISTANCE OF THE NOCTURNAL DRAINAGE 
FLOW. 

$$
COBB