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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 212158

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Thu Nov 21 2019

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 1800 UTC surface analysis and satellite imagery through 
2100 UTC.


A tropical wave is along 97W from 03N to 13N, moving west at 
around 10 kt. Scattered moderate isolated strong convection is 
noted from 07.5N to 10N between 96W and 99W.


The monsoon trough extends from 11.5N72.5W TO 05N79W TO low pres 
1010 MB near 08.5N88.5W TO 11.5N110W TO low pres 1011 MB near 
10N115W TO 09N120W. The ITCZ continues from 09N120W to beyond 
12N140W. Widely scattered moderate isolated strong convection is 
noted from 07.5N TO 10N between 96W AND 108W. Scattered moderate 
to strong convection is noted from 11.5N TO 16N between 102W AND 
110W and from 10N TO 18N between 110W AND 118W.


A cold front continues to move southeastward across Baja 
California Sur and the central Gulf of California this 
afternoon. Strong SW winds across the northern Gulf of 
California this morning have diminished to 15-20 kt in recent 
hours. The front will move across much of the Baja California 
peninsula before stalling and weakening over the southern Gulf 
of California and Baja California Sur near Cabo San Lazaro on 
Fri. Winds will continue to diminish over the northern Gulf of 
California through this evening. Off the Pacific coast of Baja 
California, mostly moderate to fresh W to NW winds behind the 
front will diminish to around 10 kt this evening as high 
pressure builds into the region in the wake of the front. Longer 
period NW swell is following the front as well. The swell will 
propagate SE and encompass the entire offshore waters of Baja 
California, with heights of 8 to 10 ft reaching as far south as 
20N through late tonight, before gradually subsiding below 8 ft 
into Sat. 

Seas are 4 to 6 ft in a mix of NW and SW swell over the offshore 
Mexican waters south of Cabo Corrientes. Winds may briefly 
increase fresh to strong off Cabo Corrientes late Fri as high 
pressure builds in the wake of the cold front. Looking ahead, 
another round of strong gap winds can be expected across the 
Gulf of Tehuantepec by late Sat into early Mon.


Fresh to locally strong NE-E winds are expected to pulse across 
the Gulf of Papagayo tonight with seas building to around 7 ft 
night. Gentle to moderate NE winds will prevail N of the monsoon
trough afterwards. Gentle to moderate southwest monsoonal flow 
will continue across the offshore waters of Costa Rica, Panama, 
Colombia, and Ecuador for the next several days, along with light
to moderate long period SW swell.


A broad area of low pressure is centered near 10N115W, drifting 
westward, and is interacting with a mid/upper trough. This 
interaction is supporting a large area of showers and 
thunderstorms from near the low pressure northward to just south 
of the Revillagigedo Islands. This low is forecast to gradually 
shift west across the tropics for the next few days. Easterly 
winds to around 20 kt could persist across the N semicircle of 
this low during this time. 

A cold front reaches from Baja California Sur near 26N112W to 
21N123W to 24N140W. The front will move as far south as 18N to 
20N through Fri before stalling and dissipating. The front has 
temporarily disrupted the subtropical ridge, producing only 
moderate to locally fresh NE to E tradewinds farther south into 
the deep tropics north of the ITCZ. Fresh NE winds are possible 
west of 130W by late week as high pressure builds behind the 
front farther east. This will coincide with a push of long 
period NW swell forecast to reach the forecast waters north of 
20N west of 130W by tonight, with seas peaking near 12 or 13 ft 
by Fri.

Looking ahead, global models are indicating another vigorous deep
layer trough digging into the waters north of 20N Sat into Sun. 
A broad surface trough is forecast to form between 120W and 125W 
north of 18N related to the upper feature. A broad area of fresh 
to strong winds and building seas are to be expected between the 
trough and high pressure north of the area due to this 
developing pattern.