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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 170252

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Mon Jun 17 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 0000 UTC surface analysis and satellite imagery through
0245 UTC.


A presently ill-defined tropical wave over the western Caribbean 
Sea may possibly enter the far eastern Pacific Mon night.

A tropical wave with axis along 110W from 05N to 15N is moving 
westward at 15-20 kt. Scattered showers and thunderstorms are 
seen within 90 nm either side of the wave from 12N to 15N.

A tropical wave with axis along 127W from 05N to 15N is moving 
westward at about 17 kt. Scattered moderate convection is within
120 nm east of the wave from 10N to 13N.


The monsoon trough axis extends from a 1008 mb low over NW 
Colombia to 08N79W to 10N87W to 09N100W to 10N110W and to 
11N122W, where latest scatterometer data indicated that it 
transitioned to the ITCZ along 10N and continues to 128W and 
to 140W. Scattered moderate to isolated strong convection is 
within 120 nm north of the trough 111W and 115W, and also south
of the trough within 60 nm of 07N118W. Scattered moderate 
convection is within 30 nm of the trough between 96W and 98W.



The pressure gradient between a high pressure ridge west of Baja 
California and a low pressure trough along the Baja California 
peninsula is maintaining moderate northwest to north winds 
across most of the adjacent offshore waters where seas remain in 
the 4-5 ft range. Winds and seas off Baja California will change
little through early on Mon as the ridge remains over offshore 
waters. However, winds will increase to fresh speeds near the 
coast this evening, mainly over the region between Punta Eugenia
and Cabo San Lazaro. Low pressure is expected to cover a rather 
expansive area over the southwestern United States and along 
California by late Mon afternoon in response to a sharpening mid 
/upper-level trough that will pass over those regions. This will 
result in the weakening of the ridge allowing for winds to 
briefly diminish through middle part of the upcoming week.

Satellite imagery shows isolated showers and thunderstorms are 
within an area bounded from 12N to 18N between 100W and 107W.

Mainly gentle southwest to south winds prevail over the southern 
half of the Gulf of California. These winds will increase to 
gentle to moderate southeast to south winds over the entire Gulf 
tonight through Mon. These winds then become light and variable 
on Tue and through Wed evening. Winds will increase to fresh 
speeds over the far northern part of the Gulf Mon night before 
diminishing to moderate speeds early on Tue. 

Long-period southwest swell is along the Mexican offshore 
waters, however the seas will remain in the 5-6 ft range through 
the middle of the upcoming week.


Fresh to strong nocturnal offshore winds will continue pulsing 
across the Gulf of Papagayo region through the upcoming week, 
with seas peaking around 7-8 ft downstream of the Gulf. 
Otherwise, fairly tranquil conditions will persist off Central 
America under a weak pressure pattern. Gentle to moderate south 
to southwest flow along with scattered showers and isolated
thunderstorms will prevail south of the monsoon trough through 
much of the upcoming week. 

Long-period southwest swell propagating through the southern 
waters will build the waveheights to 9 ft between Ecuador and 
the Galapagos Islands through the remainder of this weekend. 
Wave model guidance suggests that another set of south to 
southwest swell will propagate through the southern waters west 
of 85W Tue night through Thu building waveheights there to a 
peak of 8 ft again before they begin to subside late on Thu. 


A high pressure ridge prevails across the northern waters. 
Moderate to fresh northeast winds are between the ridge and the 
ITCZ west of 116W. Latest altimeter data continue to show seas 
in the 5-7 ft range in this region. Moderate to fresh winds are 
expected to persist mainly south of 20N into early next week as 
a couple of tropical waves moves south of the ridge.

Long period southwest swell will continue to propagate through 
high seas areas east of 120W through tonight. Seas will remain 8 
to 9 ft south of the Equator through the middle of the upcoming 
week, as a reinforcing set of southwest swell is expected to 
reach the far southwestern waters by Mon night. Expect 8-9 ft 
seas south of the Equator and west of 100W by Tue. Elsewhere, 
northwest to north swell will propagate through the far northern 
waters west of about 125W beginning on Mon night and continuing 
through Wed night as strong high pressure builds southward to 
the north of the area and while low pressure lingers offshore 
California. Waveheights associated with the swell will likely 
build to 8-10 ft north of 28N.