000
AXPZ20 KNHC 181511
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE JAN 18 2011

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS CENTERED ALONG 05N77W 
TO 04N88W TO 05N94W TO 04N99W TO 09N112W TO 08N125W TO 06N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM N AND 
30 NM S OF AXIS E OF 79W. SCATTERED MODERATE CONVECTION WITHIN 
150 NM N AND 120 NM S OF AXIS BETWEEN 110W AND 123W. 

...DISCUSSION...

HIGH PRESSURE 1029 MB IS CENTERED NEAR 38N132W WITH RIDGE 
EXTENDING SE TO NEAR 23N119W. THE PRESSURE GRADIENT BETWEEN THE 
HIGH PRESSURE AND LOWER PRESSURE ASSOCIATED WITH THE ITCZ IS 
MAINTAINING 20 KT TRADE WINDS FROM 10N TO 15N W OF 134W. ACTIVE 
CONVECTION IN THE ITCZ DUE TO ENHANCED LATENT ENERGY FLUX 
AND CONVERGENCE FROM THE FRESH TRADES THE PAST FEW DAYS HAS 
INDUCED A FEW SURFACE TROUGHS IN THE ITCZ. EVEN THOUGH THE 
COVERAGE OF THE TRADEWINDS HAS DECREASED THE PAST COUPLE OF 
DAYS...LOCALLY HIGHER PRESSURE GRADIENT BETWEEN THE TROUGHS AND 
THE SURFACE HIGH PRESSURE MENTIONED ABOVE IS MAINTAINING TRADES 
TO 20 KT LOCALLY N OF THE TROUGHS. THIS CONTINUES TO MAINTAIN 
ENOUGH CONVERGENCE TO MAINTAIN THE CONVECTION AS MENTIONED IN 
THE ITCZ SECTION ABOVE. LONG PERIOD NW SWELLS GENERATED FROM A 
LARGE AND INTENSE STORM CENTER WELL NW OF THE REGION PREVAIL 
OVER THE NW PART OF THE AREA WITH COMBINED SEAS TO 13 FT. THESE 
SWELLS WILL SPREAD SE THROUGH THE NEXT 48 HOURS WHILE SLIGHTLY 
SUBSIDING. 

$$
AL