181 
axpz20 knhc 201006
twdep 
Tropical weather discussion
NWS TPC/National Hurricane Center Miami FL
0405 UTC Thu Nov 20 2008
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...
axis along...05n78w to 06n85w to 05n95w to 08n140w.  Scattered 
moderate convection within 90 nm of axis W of 130w and within 60 
nm of axis from 106w to 110w. Isolated moderate convection E of 
85w.
...Discussion...
upper levels
large amplitude upper level trough extends from 32n115w SW to 
22n120w then S 08n120w.  Trough remains blocked from moving 
further E by large mid-upper level anticyclone centered over 
Colombia.  Another ridge upstream from trough helping advect 
tropical moisture into E pac mostly W of 130w.  Ridge over 
Colombia feeding plenty of tropical moisture across Central 
America to ITCZ E of 115w with minor deep convection noted E of 
110w.  
Surface
cold front lies just NW of area expected to move into NW portion 
of basin as dissipating front over next 12 hours.  High pres  
center 1023 mb at 29n130w has weak ridge extending se to 18n110w.
Gap winds...
strong pres gradient remains across Isthmus of Tehuantepec with 
gale force N-NE winds continuing across area.  Winds expected 
to drop below gale force in 12 hours before picking up again in 
another surge of N-NE winds likely to reach storm force daytime 
and early evening Fri. 
Gulf of papagayo ship reports confirm strong NE winds with 8 ft 
seas.  Winds forecast to weaken in 24-48 hour timeframe.
$$
Wally Barnes