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Eastern North Pacific Tropical Weather Discussion



774 
AXPZ20 KNHC 160405
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
0405 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 0000 UTC surface analysis and satellite imagery through 
0300 UTC.  

...SPECIAL FEATURE...

A broad area of low pressure is analyzed as two weak 1008 mb 
surface lows at 13N136W and 11N139W. Strong easterly trades are 
observed from 11N to 21N between 132W and 140W with seas to 11 
ft. Scattered moderate and isolated strong convection is 
currently observed within 150 nm either side of a line from 
14N135W to 10N140W, but lacks persistent banding. Associated 
conditions should be W of 140W early Tue. However, this system 
has high potential to become a tropical cyclone. Refer to the 
EPAC Tropical Weather Outlook under AWIPS/WMO headers 
MIATWOEP/ABPZ20 KNHC for additional information. 

...TROPICAL WAVES...

A tropical wave is analyzed N of 03N along 80W ALONG 80W and is 
estimated to be progressing W at 12 kt. Scattered moderate and 
isolated strong convection is flaring intermittently across the 
Pacific within 240 nm of the wave axis.

A tropical wave is analyzed from 05N87W to 14N88W and is 
estimated to be progressing W at 15 kt. Isolated moderate and 
strong convection is noted within 45 nm of the wave axis.

A tropical wave is analyzed from 05N100W to 14N100W 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.

.A tropical wave is analyzed from 06N112W through a 1009 mb 
surface low embedded along the wave at 11N112W to 17N111W. This 
system is moving W at 18kt. Scattered moderate and isolated 
strong convection is observed within 270 nm either side of the 
wave axis.

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

The monsoon trough extends W off the Pacific coast of Colombia 
at 08N78W and continues w through tropical waves at 08N80W, 
08N87W and 07N100W. Scatterometer winds indicate an ITCZ 
develops at 08N101W and extends NW to the surface low at 
11N112W, then turns SW to 08N124W, then NW to the surface low at 
13N136W. Except as mentioned near the tropical waves and 
tropical lows, isolated moderate to strong convection is 
observed within 150 nm either side of lines from 07N80W to 
08N102W and from 14.5N109W to 09N130W to 14N139W.     

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: Pulses of strong to near gale force 
northerly drainage flow, accompanied by 6 to 9 ft seas, will 
continue through Mon morning followed by strong northerly pulses 
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.   

Gulf of California: Moderate southerly flow will continue 
between 30N and 31N through early Mon morning. Elsewhere, light 
to gentle southerly flow expected for the next 48 hours. 
Scattered moderate isolated strong convection is dissipating 
across the Gulf of California from 17N to 31N. 

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

Gulf of Papagayo: fresh to locally strong NE-E winds will 
continue across and 180 nm downstream of the gulf waters through 
late Mon, followed by strong nocturnal pulses 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.

Extended model guidance is suggesting that 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 along 10N and W of 94W next weekend.   

REMAINDER OF THE AREA...

Refer to Special Features section above for information on a 
weak surface low near 13N136W.  

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. 

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.  

$$
Nelson