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Eastern North Pacific Tropical Weather Discussion



300 
AXPZ20 KNHC 161501
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1405 UTC Mon Jul 16 2018

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 1200 UTC surface analysis and satellite imagery through
1500 UTC. 

...SPECIAL FEATURE...

A broad area of low pressure is analyzed as a 1007 mb surface 
low near 13.5N139.5W. Strong to near gale force winds are 
observed within about 480 nm over the N semicircle of the low 
center. Scattered moderate and isolated strong convection is 
currently observed over forecast waters from 08N to 15N west of
136W. Associated conditions should be W of 140W early Tue. This 
system has a high potential to become a tropical cyclone during 
the next 5 days with gale conditions forecast within 24 hours. 
Refer to the EPAC Tropical Weather Outlook under AWIPS/WMO 
headers MIATWOEP/ABPZ20 KNHC, and Central Pacific High Seas 
Forecast under AWIPS/WMO headers HFOHSFNP/FZPN40 PHFO for 
additional information. 

...TROPICAL WAVES...

The axis of a tropical wave is near 82W N of 03N, and is 
estimated to be progressing W at 12 kt. Scattered moderate and 
isolated strong convection is noted within 180 nm of the wave
axis.

The axis of a tropical wave is near 91W N of 05N, and is 
estimated to be progressing W at 15 kt. Isolated moderate and 
strong convection is noted within 210 nm west of the wave axis.

The axis of a tropical wave is near 102W from 05N to 16N, and is
estimated to be progressing W at 15 kt. Scattered moderate and 
isolated strong convection is observed within 180 nm either side 
of the wave axis from 08N to 11N.

The axis of a tropical wave is near 113W from 05N to 15N with low
pres along the wave axis near 12N113W. This system is moving W 
at 18 kt. Scattered moderate and isolated strong convection is 
observed within 270 nm either side of the wave axis. The surface
low is forecast to lose identity by early Tue. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough extends from 08N78W to 07.5N102W. The ITCZ
extends from 07.5N102W to 18.5N109.5W. It resumes from 11N114W to
08N125W to 13N138W. Aside from convection associated to the
tropical waves and lows, scattered moderate isolated strong 
convection was noted within 120 nm S of the monsoon trough 
between 78W and 94W. Scattered moderate isolated strong 
convection was noted within 60 nm of the ITCZ. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: Nocturnal pulses of strong northerly 
drainage flow, accompanied by 6 to 9 ft seas, can be expected 
through Wed night.

A surface ridge will meander across the area from near 23N116W 
to near 14N97W this week. A moderate NW breeze will develop 
within 90 nm of the Baja Peninsula during the evenings, 
otherwise gentle anticyclonic northerly winds are expected 
around the ridge axis accompanied by 3 to 5 ft seas. 

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, 
COLOMBIA, AND WITHIN 750 NM OF ECUADOR... 

Gulf of Papagayo: Strong nocturnal gap wind pulses are expected 
across and downstream of the Gulf of Papagayo through the 
upcoming weekend.

Gentle to occasionally moderate E winds are forecast elsewhere N 
of the monsoon trough which is meandering between 07N and 10N. 
Moderate southerly winds are forecast S of the monsoon trough 
for the next several days accompanied by 4 to 6 ft seas.

Long period southerly swell, in the form of 7 to 8 ft seas, will
arrive along 03.4S to the E of 93W late Wed night, and propagate
N reaching the far offshore waters between 10N and 13N W of 93W 
during next weekend.


REMAINDER OF THE AREA...

Refer to Special Features section above for information on a 
surface low near 13.5N139.5W that has high potential to become a
tropical cyclone. 

A surface ridge will meander across the discussion area from 
32N140W to 23N116W this week, with moderate to locally fresh 
anticylonic flow forecast elsewhere around the ridge accompanied 
by 4 to 7 ft seas. 

Long period cross-equatorial swell, in the form of 7-9 ft seas, 
will move across the equator between 90W and 125W late Wed, and 
continue to propagate N across the discussion area S of 10N 
between 92W and 135W during the upcoming weekend. 

Long period northerly swell, in the form of 7-9 ft seas, will 
arrive along 32N between 125W and 132W on Thu night, and cover 
the waters from 30N to 32N between 130W and 140W during the 
upcoming weekend.  

$$
AL