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Eastern North Pacific Tropical Weather Discussion



557 
AXPZ20 KNHC 190900
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
1005 UTC Thu Jul 19 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 0600 UTC surface analysis and satellite imagery through 
0900 UTC.   

...TROPICAL WAVES...

A tropical wave is analyzed N of 05N along 92W and is estimated 
to be progressing W at 12 kt. Scattered moderate and isolated 
strong convection is noted N of 08N within 150 nm either side of 
the wave axis.

A tropical wave is analyzed from 05N105W to 16N105W and is 
estimated to be progressing W at 15 kt. Isolated moderate to 
strong convection is noted within 270 nm of the wave axis. 

A tropical wave is analyzed from 04N121W to 17N122W and is 
estimated to be progressing W at 15 kt. Scattered moderate 
isolated strong convection is noted within 300 nm of the wave 
axis.

A tropical wave is analyzed from 12N130W to 21N128W with a 1012 
mb surface low embedded along the wave at 17N. This system is 
moving W at 15 kt. Scattered moderate and isolated strong 
convection is observed N of 16N within 30 nm of the wave axis. 
Strong E winds to the N of 17N within 30 nm either side of the 
wave axis should diminish within 12 hours.

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

The monsoon trough extends W off the Pacific coast of Colombia 
at 08N78W and across the Gulf of Panama to the Pacific coast of 
Costa Rica at 08N83W then continues W through a tropical wave at 
08N92W to 08N95W where scatterometer winds indicate a transition 
to an ITCZ which extends W to 10N105W to 08N112W then turns NW 
to 14N129W where it loses identity, then resumes from 14N130W to 
10N140W.  

Except as mentioned near the tropical waves and tropical lows, 
scattered moderate isolated strong convection is observed within 
240 nm either side of a line from 05N78W to 13N126W, and within 
120 nm either side of a line from 08N130W to 12N140W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: Strong nocturnal drainage flow, accompanied 
by 6 to 7 ft seas, will continue through sunrise this morning,
then resume again on Fri night and continue through the upcoming
weekend.   

A surface ridge will meander from 23N116W to near 14N95W for the 
next few days. A moderate NW breeze will develop within about 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 through late Sat when long-period 
southerly swell will begin to propagate N through the Mexican 
offshore waters. 

Gulf of California: Moderate southerly flow will resume between 
30N and 31N on Fri night. Light to gentle southerly flow 
expected elsewhere for the next few days.  

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

Gulf of Papagayo: Fresh to strong nocturnal easterly drainage 
flow, accompanied by 6 to 8 ft seas, are expected through the 
rest of the week.

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, is 
crossing the equator, and will continue to propagate N reaching 
the far offshore waters between 05N and 14N W of 86W late Sun,
with this swell reaching the coast of Central America on Mon.  

REMAINDER OF THE AREA...   

See Tropical waves section. A surface ridge will meander across 
the discussion area from 32N140W to near 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 southerly swell, in the form of 7-9 
ft seas, is moving across the equator between 90W and 125W, and 
will continue to propagate N reaching across the discussion area 
S of 17N between 80W and 133W late Sun night. 

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

$$
Nelson