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         TROPICAL WEATHER DISCUSSION (EASTERN PACIFIC AREA) MESSAGES       

T1T2: AX
A1A2: PZ

Date: 2026-08-17

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Message File: T_AXPZ20KNHC170247_C_KWBC_20260817024813_4522426-811-TWDEP.txt

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AXPZ20 KNHC 170247

TWDEP 



Tropical Weather Discussion

NWS National Hurricane Center Miami FL

0405 UTC Mon Aug 17 2026



Tropical Weather Discussion for the eastern Pacific Ocean from

03.4S to 30N, east of 120W including the Gulf of California, and

from the Equator to 30N, between 120W and 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

0250 UTC.



...SPECIAL FEATURES...



Heavy Rainfall in Panama and Colombia: A tropical wave, currently

analyzed in the central Caribbean Sea near 75W, will cross 

Panama and northern Colombia through Mon, interacting with the 

monsoon trough and combining with enhanced divergence aloft to 

induce thunderstorms, particularly over the Darien region of 

Panama and the Choco-Colombia. Heavy rainfall from these 

thunderstorms may lead to flooding. 



...TROPICAL WAVES...



The axis of a tropical wave is along 95W from the Gulf of

Tehuantepec southward to the Equator, moving quickly westward

around 25 kt. An area of low pressure could form several hundred

nautical miles south of the coast of southern Mexico around the 

middle part of the week. Nearby convection is discussed in the 

ITCZ/monsoon trough section below.



The axis of a tropical wave is near 121W from 17N southward, 

moving quickly westward around 25 kt. Nearby convection is 

discussed in the ITCZ/monsoon trough section below. A broad 

area of low pressure could form well to the southeast of the 

Hawaiian Islands during the middle to latter part of the week.



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



The monsoon trough extends from 1006 mb low pressure over

northern Colombia at 11N74W to near the Gulf of Papagayo at

10N86W to 07N97W to 08N102W. The ITCZ extends from 08N102W to

08.5N121W, then resumes west of a tropical wave from 09N123W to

05N140W. Scattered to numerous moderate and isolated strong

convection is noted from 02N to 14.5N between 77W and 108W, from

06N to 11N between 108W and 130W, and from 01N to 06N between

138W and 140W.



...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...



See Tropical Waves section above for information on a tropical

wave that has a potential for tropical development offshore

southern Mexico next week. 



Strong to near gale north gap winds are over the Gulf of 

Tehuantepec. Fresh northwest winds are near the Pacific coast of

Baja California, locally strong near and north of Punta Eugenia.

Elsewhere, winds are moderate or weaker. Seas are 6 to 8 ft over

the Gulf of Tehuantepec, 5 to 7 ft over the remaining open 

Pacific offshore waters, and 1 to 3 ft over the Gulf of 

California. Scattered moderate convection is noted in the 

offshore waters from Guerrero southward. 



For the forecast, the pressure gradient between high pressure 

over the Gulf of America and relatively lower pressure south of 

Mexico will continue to induce pulses of strong north winds over

the Gulf of Tehuantepec through Wed night, with moderate to 

fresh pulses thereafter. Winds will reach reach near gale force 

at times tonight, Mon night and Tue nights, while resultant rough

seas are also expected. Fresh northwest winds are forecast off 

of the Baja California peninsula through Tue night, with winds 

reaching strong speeds near Punta Eugenia. Meanwhile, a surge of

strong SE winds may move from near Cabo Corrientes up across the

Gulf of California Mon night into early Tue, likely associated 

with a complex of convection.



...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, 

AND WITHIN 750 NM OF ECUADOR...



See Special Features section above for information on heavy

rainfall that may cause flooding over the next few days in

portions of Colombia and Panama.



Fresh to strong northeast to east gap winds are over the

Gulf of Papagayo region. Seas generated from earlier slightly

stronger winds have propagate well away from the source region 

to the south of 11N and west of 90W. Elsewhere, winds are 

moderate or weaker north of the monsoon trough, and moderate to 

fresh south of the monsoon trough. Seas are 4 to 7 ft in long-

period southwest swell over the remainder of forecast waters, 

except to 8 ft south of the Galapagos Islands. Thunderstorms are 

present near the monsoon trough as described above across much of

the offshore waters, with locally higher winds and seas possible

near any convection.



For the forecast, the pressure gradient between high pressure

over the western Caribbean and relatively lower pressure over 

Central America will lead to fresh northeast to east gap winds 

over Papagayo region, locally strong to near gale-force at times 

with occassionally and locally rough seas as a result. Moderate 

to fresh winds will extend away from this area across the far 

offshore waters of El Salvador and Guatemala midweek. Moderate to

fresh southerly winds will pulse south of the monsoon trough 

into Mon night. Large southerly swell will impact waters mainly 

from Ecuador to the Galapagos Islands through the next several 

days, largest expected through Wed. 



...REMAINDER OF THE AREA...



The low pressure associated with the remnants of Hernan is

opening to a surface trough located just west of the discussion

area and 140W. Some residual associated rough seas are along and

just east of 140W from 16N to 22N. Another weak developing

surface trough is just northeast, from near 25N132W to 20N135W.

Moderate to fresh winds are found from 23N to 28N between 128W

and 138W. Scattered moderate isolated strong convection is noted

on satellite imagery from 17N to 30N between 125W and 133W. Some

moderate to fresh winds are noted from 09N to 17N between 115W

and 129W near a tropical wave described above. Moderate to fresh

SE to S winds are found south of 02N and east of 126W. Winds are

moderate or weaker across the remainder of the open waters.  

Seas are 7 to 9 ft in mixed SE and SW swell south of the Equator

and west of 90W, and also elsewhere south of 03N between 110W 

and 130W.



For the forecast, winds and seas associated with the remnants of

Hernan will diminish later tonight toward 140W. Rough seas will 

prevail along and south of the Equator through the middle of the

week. An area of low pressure could form several hundred nautical

miles south of the coast of southern Mexico around the middle 

part of the week. Gradual development of this system is possible 

thereafter, and a tropical depression could develop towards the 

end of the week or next weekend while the system moves west- 

northwestward, while staying south of Mexico. In addition, a 

broad area of low pressure could form well to the southeast of 

the Hawaiian Islands during the middle to latter part of the 

week. Environmental conditions appear conducive for gradual 

development of this system, and a tropical depression could form 

towards the end of the week and into the weekend, while the 

system moves generally westward across the western portion of the

east Pacific and into the central Pacific. Regardless of 

development, expect some increasing winds and seas with this 

area.



$$

Lewitsky


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