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Eastern North Pacific Tropical Weather Discussion



506 
AXPZ20 KNHC 180345
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
1005 UTC Tue Jul 17 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.   

...TROPICAL WAVES...

A tropical wave is analyzed N of 06N along 90W and is estimated 
to be progressing W at 12 kt. Scattered moderate and isolated 
strong convection is noted within 150 nm either side of the wave 
axis.

A tropical wave is analyzed from 04N95W to 14N95 and is 
estimated to be progressing W at 15 kt. Scattered moderate 
isolated strong convection is noted within 150 nm of the wave 
axis. 

A tropical wave is analyzed from 04N111W to 15N110W and is 
estimated to be progressing W at 15 kt. Isolated moderate to 
strong convection is noted within 150 nm of the wave axis. 

A tropical wave is analyzed from 09N124W through a 1009 mb 
surface low embedded along the wave at 14N123W to 18N122W. 
This system is moving W at 15 kt. Scattered moderate and 
isolated strong convection is observed within 75 nm either side 
of a line from 13N120W to 17N124W. Strong E winds are forecast 
to the N of 14N within 45 nm either side of the wave through Wed 
morning.  

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

The monsoon trough extends W off the Pacific coast of Colombia 
at 09N78W and across the Gulf of Panama to the Pacific coast of 
Costa Rica at 08N83W then continues W to 08N94W where it loses 
identity.  Scatterometer winds indicate an ITCZ develops at 
08N97W and W to 09N116W then NW turns NW to 13N121W, then 
resumes from 12N125W to 10N125W. 

Except as mentioned near the tropical waves and tropical lows, 
scattered moderate isolated strong convection is observed within 
180 nm either side of a lines from 07N82W to 08N112W to 13N12W, 
and from 13N123W to 09N140W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: Strong nocturnal drainage flow, accompanied 
by 6 to 8 ft seas, will continue through Wed night then resume 
again on Fri night and continue through the upcoming weekend.   

A surface ridge from  23N116W to near 17N105W will expand 
further SE to near 15N100W by Thu. 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 Wed morning, then resume 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 Thu 
night with extended guidance suggesting these nocturnal 
conditions will resume on Sun night. 

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, and propagate N 
reaching the far offshore waters between 05N and 14N W of 86W 
late Sun with the swell reaching the coast of Central America 
late Mon.  

REMAINDER OF THE AREA...   

See Tropical waves section. 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 on Wed, and 
continue to propagate N across the discussion area S of 10N 
between 93W and 133W late Sat, and S of 18N E of 130W early 
Mon. 

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