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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 301015

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Fri Oct 30 2020

Tropical Weather Discussion for the eastern Pacific Ocean from
the Equator to 32N, east of 140W. The following information is
based on satellite imagery, weather observations, radar, and
meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1000 UTC. 

Gulf of Tehuantepec Gale Warning...High pressure and cooler,
denser air follow a cold front that has moved across the western
Gulf of Mexico and now extends along the far southwest Gulf of
Mexico. Recent scatterometer data and regional observations 
suggest this cooler air has punched through the Tehuantepec 
isthmus and gale are likely ongoing into the Gulf of Tehuantepec.
These winds are expected to reach 40 kt through late today then 
temporarily diminish to just below gale into Sat. A reinforcing 
front is expected to move into the southwest Gulf by late Sat, 
allowing a new round of gale force winds by Sun which should 
persist through early next week. Short period northerly swell 
will mix with longer period southerly swell to support seas in 
excess of 8 ft well downstream of the Gulf of Tehuantepec. Peak 
seas during this gale wind event are expected to build to around 
16 ft Fri afternoon and then to near 18 ft Mon evening.


A tropical wave axis is along 86W, along the east coast of 
Nicaragua, extending southward across Costa Rica to 05N, moving 
westward at 15-20 kt. Associated convection is described


The monsoon trough axis extends from 11N85W to 14N110W to beyond
10N140W. Scattered moderate to strong convection is noted from 
06N to 10N between 87W and 92W, from 10N to 13N between 95W and 
100W, and from 10N to 14N between 112W and 118W.


High pressure west of Baja California is supporting gentle to
moderate northerly breezes across the Mexican offshore waters 
off Baja California and the Gulf of California. Seas are mostly 
2 to 4 ft in both the open waters and in the Gulf of California.
Divergence aloft on the southeast side of an upper trough west 
of the area is supporting a few showers near the Revillagigedo 
Islands. Seas will build to 4 to 6 ft in the waters of Baja
California by early next week. Elsewhere, little change is 
expected through the next several days.

Farther south, moderate northerly winds are funneling off Cabo
Corrientes, and seas are likely 4 to 6 ft off the Jalisco and
Colima coasts in mostly southerly swell. Gentle winds and 3 to 5
ft elsewhere off southern Mexico outside of the Gulf of
Tehuantepec. Seas will start building tonight as increased
southerly swell moves into the area, reaching up to 9 ft off
Michoacan and Guerrero by late Sat, then subsiding into early
next week.  


Moderate south to southwest winds will prevail south of the 
monsoon trough through Sun, with isolated areas of fresh winds
this afternoon overnight ahead of an approaching tropical wave. 
Seas are expected to increase offshore of Guatemala and El 
Salvador through Sat night due to gale force winds in the Gulf 
of Tehuantepec pushing northerly waves into the area. Moderate 
offshore gap winds are expected across the Papagayo region through
Sun before turning onshore Mon.

Active weather is expected across the waters north of 05N, from 
the Papagayo region southeast into Central America and the Gulf
of Panama this afternoon and tonight. 


A broad ridge persists across the northern forecast waters west 
of 120W. The gradient between the ridge and lower pressures 
associated with the monsoon trough will support moderate to fresh
NE trade winds over an area roughly from 10N to 22N, west of 
115W, for the next several days. Seas are 6 to 8 ft across this 
region, in a mix of swell and easterly wind waves. Little change
is expected through today.

South of the monsoon trough, moderate to fresh S to SW winds 
prevail between 100W and 130W, where seas are 7-9 ft. Minor
fluctuations in winds and seas are expected across this area
through the weekend. 

Looking ahead, computer models suggest that a tropical wave
moving offshore of SW Mexico Sun and Mon could spawn a low 
pressure center forming west of the offshore waters in the 
vicinity of 10N110W by Mon morning, and move WNW through mid