000
AXPZ20 KNHC 190924
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU NOV 19 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG A LINE FROM 
08N82W TO 05N94W TO 08N107W TO 06N117W TO 08N140W. ISOLATED 
MODERATE CONVECTION CAN BE FOUND WITHIN 90 NM N OF THE AXIS 
BETWEEN 104W AND 106W AND BETWEEN 113W AND 117W. 

...DISCUSSION...

AN UPPER LEVEL TROUGH STRETCHES FROM NEAR 24N112W TO 23N128W TO 
28N140W WITH DRY AIR AND SUBSIDENCE IN PLACE N OF IT. SURFACE 
HIGH PRES IS CENTERED JUST N OF THE AREA NEAR 33N135W WITH A 
RIDGE AXIS EXTENDING TO 20N112W. A COLD FRONT WILL APPROACH THE 
NW CORNER OF THE DISCUSSION AREA LATER TODAY REACHING 30N136W TO 
28N138W BY THIS EVENING...THEN NEAR 30N128W TO 26N133W BY FRI 
EVENING WHERE IT WILL WEAKEN. THE STRONGEST WINDS AND CONVECTION 
ASSOCIATED WITH THIS FEATURE WILL REMAIN N OF 32N WITH THE FRONT 
EVENTUALLY DISSIPATING AS IT ENCOUNTERS THE RIDGE. BUILDING NW 
SWELL OF UP TO 15 FT WILL ARRIVE BEHIND THE FRONT AND WILL 
PROPAGATE THROUGH THE N PORTION OF THE WATERS THROUGH THIS 
WEEKEND. 

TO THE S...THE SUBTROPICAL JET AXIS EXTENDS FROM NEAR 24N107W TO 
21N129W TO 15N140W WITH STRONG SW FLOW TRANSPORTING MOISTURE 
MAINLY IN THE MID TO UPPER LEVELS. AN UPPER LEVEL ANTICYCLONE IS 
CENTERED S OF THE JET NEAR 12N119W. MODERATE TO STRONG 
SUBSIDENCE S OF THE JET HAS SUPPRESSED CONVECTION ALONG THE ITCZ 
ACROSS THE DISCUSSION AREA THROUGHOUT THE PAST 24 HOURS. 

MODERATE NE TO E TRADES IN THE 20 TO 25 KT RANGE PERSIST MAINLY 
FROM 09N AND 25N W OF 117W AS INDICATED BY EARLY MORNING 
SCATTEROMETER PASSES DUE TO A TIGHT PRES GRADIENT BETWEEN THE 
HIGH TO THE N AND LOWER PRES ASSOCIATED WITH THE ITCZ. WIND 
WAVES COMMINGLING WITH NORTHERLY SWELL CONTINUES TO RESULT IN 
COMBINED SEAS OF 8 TO 12 FT OVER THIS SAME AREA AS CAPTURED BY 
AN EARLIER JASON ALTIMETER PASS.

GAP WINDS...
N TO NE WINDS OF 20 TO 30 KT CONTINUE IN THE GULF OF 
TEHUANTEPEC. THESE WINDS WILL DIMINISH TO LESS THAN 20 KT BY FRI 
AFTERNOON AS THE PRES GRADIENT WEAKENS OVER THE AREA. TO THE 
SE...THE COMBINATION OF TIGHT GRADIENT FLOW AND DRAINAGE EFFECTS 
WILL CONTINUE TO ALL FOR 20 TO 25 KT NE TO E WINDS THROUGH THE 
GULF OF PAPAGAYO AND ADJACENT WATERS THROUGH FRI.

$$
LEWITSKY