Tropical Weather Discussion

axpz20 knhc 230954

Tropical weather discussion 
NWS National Hurricane Center Miami FL
1005 UTC Tue may 23 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 0600 UTC surface analysis and satellite imagery through 
0830 UTC.

...Intertropical convergence zone/monsoon trough... 

The monsoon trough begins over Colombia near 09n74w, extends 
across Panama and Costa Rica then veers WNW to 12n97w to 
07.5n115w. The ITCZ extends from 07n119w to beyond 06n140w. 
Widely scattered moderate isolated strong convection noted from 
04n to 13n E of 90w. Widely scattered moderate isolated strong 
convection is noted within 120 nm N and 210 nm S of trough 
between 90w and 108w. Scattered moderate to strong convection is 
noted within 75 nm N and 150 nm S of ITCZ between 123w and 


Offshore waters within 250 nm of Mexico...

Weak high pressure remains centered well offshore of northern 
California and extends a weak ridge se into the area to near 
26n120w. This is maintaining a relatively weak pressure gradient 
across the offshore waters from Baja California to Acapulco 
tonight, with moderate NW winds prevailing across the Baja 
Peninsula waters, and light NW to W winds from las Tres Marias 
to Acapulco. Seas are running 4-6 ft in mixed NW and SW swell 
and will subside to 4-5 ft by Wed. The pressure gradient will 
tighten somewhat N of 20n Wed through Fri as the ridge builds 
modestly into the region, with winds and seas increasing 

Gulf of california: mainly light and variable winds are expected 
through Thursday, with seas of 1-3 ft, except 4-5 ft in SW swell 
across the far southern waters. Model guidance suggests fresh to 
locally strong WSW winds N of 29n Thursday to Saturday as low 
pressure prevails N of the region. These winds shooting through 
the gaps in the higher terrain of baja will increase seas 
significantly, reaching 6-7 ft each night during the nocturnal 
wind Max.

South of 16n including the Gulf of tehuantepec: broad and weak 
low pressure has persisted across the offshore waters SW of 
Tehuantepec the past few days, and the low has drifted W to near 
100w and nearly dissipated. Gentle to moderate se winds 
occurring between Tehuantepec and offshore of Acapulco will 
gradually weaken and veer S to SW through Wed.

Offshore waters within 250 nm of Central America, Colombia, and 
within 750 nm of Ecuador...

Moderate se to E winds prevail between the papagayo region and 
Tehuantepec tonight, to the east of the dissipating low along 
100w, where seas are 5-7 ft in SW swell. Expect these conditions 
to continue today before gentle to moderate SW to W monsoonal 
winds spread N of 09n and into the coastal waters tonight 
through Tue.   

Moderate southwesterly winds are expected S of 09n through 
Thursday night, with seas subsiding slightly tonight through Wed 
before a new pulse of SW swell arrives Thu through late Fri. 

Remainder of the area...

a weak ridge extends from a 1027 mb high near 41n137w se to near 
26n120w will reposition itself from 32n142w to 11n120w by mid 
week as a weak frontal trough sweeps southeastward across the 
waters north of 30n Tuesday and Wednesday accompanied by long 
period NW swell. This will build seas to 6-8 ft along 32n 
between 120w and 135w. Elsewhere north of the convergence zone 
the weak ridge will maintain moderate trade winds S of 18n, with 
seas of 5-7 ft expected. 



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