Eastern North Pacific Tropical Weather Discussion (Text)

AXPZ20 KNHC 220925

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Thu Oct 22 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
0815 UTC. 


A tropical wave is analyzed along 108W from 05N to 14N, moving 
west at 10-15 kt. Associated convection is described below.

A tropical wave is analyzed along 125W/126W from 07N to 17N, 
moving W at 10 to 15 kt. An associated 1009 mb low pressure 
center is located near 15N121W and moving in tandem with the 
wave. Associated convection is described below with the low and
also near the monsoon trough.


The monsoon trough axis extends from 10N74W to 12N93W to low 
pres 1009 mb near 08.5N103W to low pres 1009 mb near 15N121W to 
11N132W. The ITCZ continues from 11N132W to beyond 10N140W. 
Scattered strong convection is inland over Colombia and extends 
over coastal waters out to 60 nm between 03N and 08N. Scattered 
moderate to strong convection is noted from 07N to 11N between 
99W and 113W. Scattered moderate isolated strong convection is 
noted from 08N to 14N between 130W and 140W.


The strong high pressure ridge across the NE Pacific has shifted
westward of 120W. The resultant pressure gradient between the 
ridge to the west and a trough along the Baja California
Peninsula has relaxed, and is supporting gentle N to NW winds 
across the offshore waters of Baja California, except for
moderate winds surrounding Punta Eugenia. Light southerly winds
have developed across the Gulf of California. Farther south, 
except for the Gulf of Tehuantepec, gentle NW winds persist. 
Seas offshore of Baja are generally in the 5 to 6 ft range in 
mixed N and SW swell, 4 to 6 ft south of Cabo San Lucas, and 3 
ft or less across all but the mouth of the Gulf of California.

Winds will diminish slightly offshore of Baja California on Thu as
the ridge shifts further westward. Mostly gentle to moderate 
winds and seas 5 ft or less will persist elsewhere. Winds will 
remain light to gentle through the end of the week across the 
offshore Baja California waters with seas remaining 5-6 ft Thu 
and Fri. However, gale force northerly winds offshore of 
northern California will push new N swell across the outer 
waters tonight through the Fri and raise seas across the offshore
waters of Baja California Norte to 6-9 ft by Fri.

Gulf of Tehuantepec: Fresh N winds are expected to remain near 
20 to 25 kt across the Gulf north of 15N through Thu, and extend
only 90-120 nm downwind in a relatively narrow plume. Nocturnal 
pulses of 25-30 kt will return into the weekend. 

Looking ahead, the first strong cold front of the season will
move across northern Mexico and much of the Gulf of California
Sun night through Mon. This will bring strong westerly gap winds
across north and central portions of the Gulf Sun afternoon 
through Mon, before strong northerly winds begin to spread 
southward across the basin Mon night and Tue. 


Gentle to moderate SW winds prevail south of the monsoon trough 
to near the equator, east of the Galapagos Islands. Seas south of
Costa Rica and Panama are 6 to 8 feet in mixed SW swell. These 
conditions will continue with little change overnight before 
long period SW swell fades across the region through Thu, and
seas fall below 8 ft. The SW winds are expected to freshen again
Fri into the weekend.

Broad low pressure across the southwest Caribbean has begun to
shift NW across the Yucatan Peninsula and Channel. Associated
weather across the waters of Panama and Costa Rica, has also 
shifted northward and is expected to affect Nicaragua and Central
America Thu. 


A 1032 mb high pressure near 45N136W extends a broad ridge S 
into the discussion area and then SE to near 21N117W, and is 
supporting moderate to fresh NE to E winds from roughly 12N to 
27N mainly east of 125W. Seas are generally 6-8 ft across this 
zone. Expect little change in this pattern through the end of the

Low pressure of 1009 mb along the monsoon trough near 15N121W 
follows a tropical wave along 125W/126W. This low will shift WNW
over the next several days and move south of the ridge. As this 
occurs, the pressure gradient across the NW semicircle of the 
low will produce a zone of winds around 20 kt, and occasionally 
to 25 kt, with seas building to 8-9 ft Sat through Sun.


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Page last modified: Thursday, 22-Oct-2020 09:25:46 UTC