000
AXPZ20 KNHC 161536
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1536 UTC Sun Jul 16 2017

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 FEATURES... 

Hurricane Fernanda is centered near 12.4N 127.4W at 16/1500 UTC 
or about 1182 nm WSW of the southern tip of Baja California, 
moving WNW at 11 kt. Estimated minimum central pressure is 953 
mb. Maximum sustained winds are 115 kt with gusts to 140 kt. 
Numerous strong convection is within 60 nm in the NE semicircle 
and 90 nm in the SW semicircle. Scattered moderate and isolated 
strong convection is elsewhere within 300 nm in the NE semicircle
and 120 nm in the SW semicircle. Some fluctuations in intensity
are possible today, with gradually weakening for the remainder 
of the forecast. Large swells will spread and expand out ahead of
Fernanda to the NW and W during the next few days, and are 
expected to reach the Hawaiian Islands early Tuesday. See latest 
NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 
for more details.

A broad area of 1011 mb low pressure about 270 nm SW of Acapulco
near 14N103W, Mexico is associated with a tropical wave N of 08N,
moving W at 10 kt across the area. Associated winds on the NE 
side are fresh with seas to 8 ft in mixed southerly swell. 
Scattered moderate to strong convection is within 210 nm in the 
NE quadrant, with scattered moderate convection from 10N to 12N 
between 104W and 109W. The low is forecast to move generally WNW 
during the next couple of days, and has a medium chance of 
tropical cyclone formation within the next 48 hours.

...TROPICAL WAVES... 

A tropical wave extends from 08N103W to the 1011 mb low pressure
area near 14N103W. Please refer to the Special Features section
above for more details on the tropical wave and the associated 
elongated low pressure developing along the wave.

A tropical wave is from 08N to 16N along 114W/115W moving W at 
10 kt. Very active convection persists with scattered moderate to
strong from 07N to 15N between 112W and 116W. Scattered moderate
and isolated strong convection is also from 08N to 12N between
116W and 121W. A weak area of low pressure may be developing
along the tropical wave near 12N. 

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

The monsoon trough axis extends from 09N75W to 09N93W to low
pressure near 14N103W to 11N121W, where it breaks to the E of 
Hurricane Fernanda, then resumes from 11N130W to 08N139W. The 
intertropical convergence zone axis extends from 08N139W to 
08N140W. Scattered moderate and isolated strong convection is
from 06N to 08N between 79W and 86W, from 09N to 13N between 85W
and 90W, and also from 04N to 08N between 90W and 97W. Scattered
moderate convection is from 05N to 08N between 130W and 140W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see the special features for information on a broad area
of low pressure SW of Acapulco, Mexico.

A surface trough will develop through Monday from the coast of 
southern California southward to off the coast of the Baja 
California peninsula. This will block the advance of the 
subtropical ridge into the region and maintain generally gentle 
to moderate winds off the Baja California peninsula through late 
week. Seas will still be 5 to 7 ft however, in a mix of 
northerly and longer period S to SW swell. 

Farther S, moderate to fresh easterly winds will sweep across 
the Revillagigedo Islands on the N side of low pressure passing 
to the WSW of the region early to mid week.

Gentle southerly flow will persist across the Gulf of California,
except for moderate southerly flow over the northern Gulf. 

Fresh gap winds will pulse across the Gulf of Tehuantepec
starting mid week related to high pressure north of the area and
lower pressure to the S related to passing tropical waves. These
winds will likely further increase to fresh to strong by the end
of the week into next weekend.
    
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...

In the Gulf of Papagayo, moderate to fresh offshore winds will 
pulse to fresh each night with nocturnal drainage through the
week, occasionally building seas close to 8 ft.

Gentle to moderate southerly winds are expected S of the monsoon
trough axis. Long period cross-equatorial southerly swell and 6 
to 7 ft seas will continue to propagate into the waters reaching
the coast of Central America through the day. Another pulse of 
large southerly swell will move into the waters by Tuesday.

REMAINDER OF THE AREA...

Please see the special features section for information on 
Hurricane Fernanda.

The post-tropical remnant low of Eugene has finally dissipated,
leaving a weak trough from 29N130W to 25N131W.

Swells generated by Fernanda will propagate away from the center
across tropical waters W of 120W the next several days.  
Northerly swell of 6 to 8 ft will propagate into the waters N of 
25N and W of 120W starting Monday, mixing with southerly swell 
generated from Fernanda by Tuesday, with 7 to 9 ft combined 
seas. Elsewhere outside of the region within 300 nm of the path 
of Fernanda, winds will remain generally light to moderate with 5
to 7 ft seas. 

$$
Lewitsky