Eastern North Pacific Tropical Weather Discussion (Text)

AXPZ20 KNHC 230332

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Thu Jan 23 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 0000 UTC surface analysis and satellite imagery through 
0315 UTC.


A trough extends from low pressure of 1010 mb over northwestern 
Colombia near 10N75W southwestward to the coast at 07N77W and 
continues to 06N80W to 07N87W to low pressure of 1009 mb near 
06N91W to 04N91W and to 05N99W, where latest scatterometer data 
indicates the ITCZ begins and continues to 04N99W to 05N110W and 
to 06N120W to 10N135W, where it is bisected by a trough that 
extends from 15N135W to 05N136W. It resumes at 08N137W and to 
beyond 08N140W. Scattered moderate to isolated strong convection 
is within 120 nm south of the ITCZ axis between 130W and 135W.
Scattered moderate convection is seen within 60 nm south of the 
ITCZ axis between 82W and 88W.


High pressure west of Baja California is supporting moderate to 
locally fresh northwest to north winds along the Pacific Coast of
Baja. This wind pattern should continue for the remainder of 
this week as the high remains in place. Winds are light to 
moderate over the northern Gulf of California and moderate over 
the southern Gulf of California. Moderate to fresh northwest 
winds are expected over the central and southern Gulf of 
California tonight through Thu night as high pressure builds over
the U.S. Great Basin.

The earlier gale force north to northeast winds that were present
over the Gulf of Tehuantepec have diminished to strong speeds. As
the pressure gradient over southeastern Mexico continues to
slacken these winds will continue to further diminish to light to
gentle speeds by early Thu, with waveheights lowering to 3-4 ft.

Long-period northwest swell propagating across the region will 
reach the Revillagigedo Islands early on Thu. Waveheights will 
slowly subside through Fri as the swell decays. Another round of 
long-period northwest swell associated with an approaching cold 
front will reach the Baja California waters beginning late Fri 
night and build waveheights to 8 ft or greater there during the 
upcoming weekend.


A high pressure ridge over the western Caribbean will continue 
to support strong northeast to east winds over and downstream of 
the Papagayo region through Thu morning, strongest at night. 
Seas will build to 8 ft each morning following the peak winds. 
Winds will taper over the Gulf of Papagayo during the remainder 
of the week as the ridge weakens.

Swell generated by the current Tehuantepec gale force wind event
will impact the Guatemala and El Salvador offshore waters 
through tonight, then waveheights will subside Thu as the swell 

Moderate to fresh N winds over the Gulf of Panama region will 
become fresh to locally strong Fri night, then gradually decrease
to moderate by Mon night.


A rather vigorous upper-level trough approaching the area from
the west. It has helped to develop a surface trough along a 
position from 15N135W to 05N136W. Latest satellite imagery shows 
areas of rain with scattered showers from 10N to 15N between 
130W and 136W. The pressure difference between high pressure 
ridging associated with a 1026 mb high center analyzed near 
31N127W and the surface trough is sustaining a broad area of 
fresh to strong northeast winds roughly from 08N to 22N and west 
of about 126W. With trough expected to remain nearly stationary 
over the next couple of days, and while the high pressure is 
only expected to weaken slightly, expect for this area of fresh 
to strong winds to change little, with these winds at times 
possibly reaching to near gale force. There is some chance that 
the upper-level trough may form an upper-low along providing 
impetus for the surface trough to develop into a low. 
Waveheights with these winds are forecast to be in the range of 
10-12 ft.

Otherwise, combined seas greater than 8 ft in prevalent long- 
period northwest to north swell will dominate the discussion 
area west of about 114W, along with waveheights in the range of 
8-11 ft through Thu night. The swell will diminish in coverage 
on Fri along with it decaying as well, by which time it is 
forecast to be confined to south of 15N between 105W and 131W, 
with waveheights to 9 ft. 

Another set of long-period northwest swell will reach the 
northwest part of the area Thu, then propagate southeastward
and decay during the upcoming weekend. The cold front ushering 
the swell into the region is expected to weaken as it crosses the
far northern waters Sat and Sun.


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Page last modified: Thursday, 23-Jan-2020 03:32:30 UTC