000
AXPZ20 KNHC 252152
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED NOV 25 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...ITCZ...

AXIS ANALYZED FROM 08N78W TO 05N95W TO 07N111W TO 07N115W TO 
08N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION NOTED 
FROM 05N TO 11N E OF 91W AND ALSO WITHIN 120 NM EITHER SIDE OF 
THE ITCZ AXIS W OF 110W.

...DISCUSSION...

AN UPPER ANTICYCLONE NEAR 12N142W HAS A SHORTWAVE RIDGE 
EXTENDING N TO A CREST NEAR 36N130W. THE MID AND UPPER LEVELS 
ARE DRY N OF 12N W OF 121W. A TROPICAL ANTICYCLONE IS ESTIMATED 
NEAR 12N103W WITH VERY DRY AIR AND SUBSIDENCE ALOFT S OF 15N TO 
THE EQUATOR BETWEEN 90W AND 105W HELPING TO SUPPRESS ANY 
CONVECTION ACROSS THIS AREA AND ALONG THE ITCZ AXIS. AN UPPER 
TROUGH EXTENDS FROM NEAR 28N111W TO 17N130W. MOISTURE IS BEING 
ADVECTED ALONG AND AHEAD OF THE TROUGH AXIS FROM THE SW UP 
ACROSS THE BAJA PENINSULA INTO N CENTRAL MEXICO. CONVERGENT FLOW 
ALONG THE ITCZ AXIS S OF THIS TROUGH IS ENHANCING CONVECTION W 
OF 110W. A SECOND UPPER LEVEL TROUGH IS SWINGING E ACROSS THE 
CENTRAL GULF OF MEXICO. CONVERGENT FLOW BETWEEN THE BASE OF THIS 
TROUGH IN THE NW CARIBBEAN AND STRONG ANTICYCLONIC FLOW ACROSS 
THE REMAINDER OF THE CARIBBEAN IS ENHANCING CONVECTION OVER 
CENTRAL AMERICA AND TO THE W ALONG THE ITCZ IN THE E PACIFIC E 
OF 91W.

AT THE SURFACE...HIGH PRESSURE CONTINUES TO DOMINATE THE AREA W 
OF 110W. NE TO E TRADES IN THE 20 TO 25 KT RANGE PERSIST ALONG 
AND W OF THE RIDGE TO 140W. STRONGER HIGH PRESSURE WILL PASS N 
OF THE AREA THU NIGHT THROUGH FRI EXPANDING THE AREA OF NE 
TRADES. SEAS OF 8 TO 12 FT ARE ALSO CURRENTLY NOTED SW OF THE 
RIDGE WITH NW SWELLS COVERING THE ENTIRE AREA W OF 114W. ANOTHER 
SET OF LONG PERIOD NW SWELLS IS EXPECTED TO MOVE INTO THE NW 
PORTION OF THE FORECAST AREA BEGINNING LATE TONIGHT WITH SEAS 
BUILDING TO 16 FT. 

...GAP WINDS...
A 1624 UTC ASCAT PASS CAPTURED NORTHERLY WINDS OF 20 TO 25 KT IN 
THE GULF OF TEHUANTEPEC AND WINDS WILL INCREASE TO GALE FORCE 
WITHIN THE NEXT 6 HOURS...THEN WILL INCREASE FURTHER TO MINIMAL 
STORM FORCE BY EARLY FRI.

STRONG HIGH PRESSURE OVER THE NW CONUS COMBINED WITH A LOW 
PRESSURE TROUGH ALONG THE BAJA CALIFORNIA PENINSULA IS 
MAINTAINING A TIGHT PRESSURE GRADIENT RESULTING IN STRONG 
NORTHERLY WINDS IN THE NORTHERN GULF OF CALIFORNIA. AN 1800 UTC 
ASCAT PASS CAPTURED 20 TO 25 KT WINDS IN THE GULF N OF 28N. THE 
GRADIENT WILL GRADUALLY DECREASE OVER THE NEXT 24 HOURS 
DIMINISHING THE WINDS TO BELOW 20 KT.

EASTERLY TRADES IN THE W CARIBBEAN WILL CONTINUE TO MAINTAIN 
SURGES OF 20 TO 25 KT IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO 
FOR THE NEXT FEW DAYS. 

$$

LEWITSKY