125 
axpz20 knhc 100905
twdep 
Tropical weather discussion  
NWS TPC/National Hurricane Center Miami FL
1005 UTC Tue Nov 10 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 
0730 UTC.
...ITCZ...
The ITCZ axis extends from 09n79w to 07n95w to 12n115w to 
07n135w to 07n140w. Scattered moderate convection can be found 
on either end of the ITCZ over forecast waters...specifically 
within 120 nm either side of the ITCZ axis E of 86w and within 
45 nm either side of the ITCZ axis W of 135w. Isolated moderate 
convection can be found within 120 nm N of axis between 114w and 
124w and within 120 nm S of axis between 110w and 114w. This 
convection is in the vicinity of two surface troughs embedded in 
the ITCZ from 13n122w to 08n126w and from 14n112w to 
09n115w...respectively.
...Discussion...
A high pres ridge stemming from a 1022 mb high near 31n134w and 
extending se to near 17n105w dominates north waters at the 
surface. This high pres system is part of a larger North Pacific 
ridge that is currently being compromised by a stationary front 
just north of the forecast area. While this front is expected to 
dissipate N of forecast waters today...long period NW swell from 
the system has already pushed well into waters W of 105w and 
significant wave heights have subsided to the 10 to 13 ft range 
over much of this area. This swell will continue to slowly 
subside to the 8 to 10 ft range over the next two days with  
wind waves stemming from the easterly trade winds generally 
found...according to the 0130 and 0310 UTC Quikscat 
passes...from 10n to 20w W of 113w helping to keep wave heights 
above 8 ft over much of the region. A new cold front will 
approach NW waters overnight Wed night that will reinvigorate 
the NW swell. The surface high pres over N waters will 
reorganize to the NW in response to this cold front. The trade 
winds are expected to shrink W and diminish to 20 kt over the 
next few days as a result.
Broad upper level diffluence between a weak upper trough from 
20n120w to 10n125w and an anticyclone centered near 12n105w is 
enhancing convection along the ITCZ over waters between 110w and 
125w. See the ITCZ section above for details on this 
convection. The trough and anticyclone are both expected to 
migrate E over the next two days. 
Closer to shore...35 to 50 kt W-NW upper flow is inhibiting 
convection over Mexico and adjacent waters N of 19n. To the 
S...broad upper level diffluence between an anticyclone over the 
NW Caribbean and troughing from northern Peru to just W of the 
galapagos is enhancing convection over Panama and Costa Rica on 
the eastern side of the ITCZ.
Gap winds...
the 0402 UTC ascat pass showed 20 to 30 kt winds funneling 
through The Isthmus of Tehuantepec into the Pacific from the 
western Gulf of Mexico on the western side of Atlantic Tropical 
Storm Ida. N to NE winds in the Gulf of Tehuantepec will 
increase to gale force by sunrise and persist through the 
forecast period...with winds just below storm force expected Wed.
$$
Schauer