467 
axpz20 knhc 080328
twdep 
Tropical weather discussion  
NWS TPC/National Hurricane Center Miami FL
0405 UTC sun Nov 08 2009
Tropical weather discussion for the eastern Pacific Ocean from 
the Equator to 32n...east of 140w. 
Based on 0000 UTC surface analysis and satellite imagery through 
0315 UTC.
...Tropical lows...
.Low pres is centered near 12.5n90w estimated at 1007 mb and is 
nearly stationary. The circulation is mostly a swirl of low 
level clouds lacking convection.
.Low pres is centered near 12n118.5w estimated at 1008 mb and is 
nearly stationary. The surface low is under an upper ridge and 
the associated upper diffluence was enhancing intermittent 
convection but has since decreased considerably today.
...ITCZ...
The ITCZ axis extends along 09n83w to 07n99w to 12n118w to 
08n140w. Scattered moderate isolated strong convection is noted 
within 120 nm either side of line 07n106w to 11n112w and also 
within 150 nm of 09n126w and within 120 nm of 08n140w.
...Discussion...
A broad upper ridge dominates the discussion area S of a line 
from 00n132w to 28n122w to 00n109w. Debris moisture from 
convection W of the area is streaming E merging with the 
moisture from convection centered on 08n140w. The tropical plume 
continues NE along the NW periphery of the ridge eventually 
fanning out over the tropics from 14n to 23n between 123w and 
133w. ITCZ convection is also enhanced from 08n to 10n between 
123w and 130w...and also along the se periphery of the ridge as 
previously mentioned...with most of the debris moisture 
spreading E and se...but the upper levels are so dry immediately 
N and S of the ITCZ the moisture dries out fairly quickly. 
An upper trough is noted over the subtropics to the NW of the 
previously described ridge...from 24n130w to 15n140w with dry 
upper air W of the trough. An upper cyclone is over NW old 
Mexico near 29n110w. Dense upper moisture is observed over the 
NE semicircle of this cyclone and is spreading N across the SW 
conus where the moisture merges with another plume of moisture 
from the central Pacific that stream E over the area N of 30n. 
An upper trough extends se from this cyclone across Mexico to a 
base near 08n93w. Upper dry air is sweeping E across the 
discussion area from 24n to 27n between 145w and 120w then the 
dry air turns se through the upper trough and continues to push 
se right into the trough base in deep tropical Pacific.
An upper anticyclone is over the SW Caribbean near 13n77w with a 
ridge extending SW to near 09n87w. Convection was enhanced 
earlier under the ridge over NW Colombia and also over most of 
Panama and Costa Rica and Nicaragua...and the debris moisture is
now spreading SW over the discussion area NE of a line from 
02n79w to 09n87w.
At the low levels a ridge extends along 32n140w to 15n110w and 
is the predominate feature. N to NE to E winds are generally 15 
to 20 kt through the ridge. Large NW swells will spread into the 
area W of 105w well into next week.
Gap winds...
N winds at 20 to 25 kt expected to continue in and just 
downstream of the Gulf of Tehuantepec tonight into sun and 
finally diminishing below 20 kt by sunset sun. 
$$
Nelson