Tropical Weather Discussion

axpz20 knhc 170308

Tropical weather discussion
NWS National Hurricane Center Miami FL
0405 UTC sun Feb 17 2019

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 
0200 UTC.

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

The ITCZ extends from 06.5n88w to 04n93w to 01n110w to 
00.5n129w. A southern hemispheric ITCZ extends from 03s84w to 
02.5s102w to 04.5s123w. Widely scattered moderate convection is 
noted within 120 nm either side of ITCZ between 87w and 103w.


Offshore waters within 250 nm of Mexico...  

A very strong high pressure ridge extends se across the 
discussion area to just southeast of the revillagigedo islands 
near 15n108w. The pressure gradient between the ridge and lower 
pressure over the SW conus and Mexico is support strong nwly 
winds across the offshore waters of Baja California and 
southward to 19n. Winds within 60 nm of the coast will soon 
increase to 25-30 kt and persist overnight. Seas across this 
area are running 8-11 ft in NW swell, while new large NW swell 
is entering the northern waters north of 28n to produce seas of 
12-16 ft. Long period NW swell of 14-18 seconds will continue to 
spread se across these offshore waters through Mon, with seas 
peaking at 10-16 ft across all waters N of 20n on sun before 
gradually subsiding to 8-12 ft Mon. 

The combination of these strong winds and large NW swell will 
produce very rough and dangerous marine conditions across the 
open waters through Mon, and generate very large and shifting 
waves along the coasts. Winds off baja will gradually diminish 
to around 15 kt Mon through Tue with seas subsiding to 8-10 ft. 
Winds and seas will further subside through early Thu morning 
before strong low pressure moves into Southern California during 
the day to bring strong to near gale force westerly winds into 
far N portions of the area. Weak troffing along and offshore of 
the coast near Manzanillo will maintain gentle and variable 
winds to the southeast of Cabo Corrientes through Mon, with 
offshore seas of 4-6 ft this evening prevailing through sun, 
then building to 5-8 ft in new NW swell Sun night through Tue.

Gulf of california: fresh nwly winds prevail across northern 
portions of the Gulf this evening while winds have freshened to 
20-25 kt south of the Tiburon basin and will continue overnight. 
Seas across southern portions are quickly building to 5-7 ft 
this evening and will reach near 8 ft tonight offshore of San 
Jose del Cabo. A weak cold front will enter the northern Gulf 
waters on Sun night supporting fresh to strong SW to W winds N 
of 29n through Mon morning. 

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

Moderate northeast winds in the Gulf of papagayo will diminish 
tonight, but resume again Mon increasing to strong at night and 
continuing through Wed morning. Light and variable winds are 
expected elsewhere through Thu except for the Gulf of Panama 
where moderate northerly winds will dominate.

Remainder of the area... 

A 1040 mb high centered well north of the Hawaiian islands near 
41n146w will persist across that region for the next several 
days, with an associated unusually strong ridge extending se and 
into the tropics near 12n107w through Mon. This pattern is 
currently producing a tight pressure gradient across the entire 
area N of 08n and W of 110w, resulting in fresh to strong 
anticyclonic wind flow W of 118w. Afternoon scatterometer data 
showed strongest winds from 22n to 28n to the west of 135w, 
where E winds were a solid 25 kt, and seas estimated at 13-16 
ft. New NW swell moving into the area has raised seas to 12-18 
ft N of 25n while elsewhere seas are in the 8 to 12 foot range. 
This strong ridge will strengthen slightly tonight into sun, and 
remain generally in place to maintain this large area of strong 
NE to E winds across W and SW sections of the discussion area. 

Winds and seas will start to subside on Mon as a deep layered 
low pressure system affecting the Hawaiian islands for the past 
several days begins to move northward, which will nudge the 
strong ridge to the east and weaken it eastward of 120w across 
the local area. Otherwise, a weak cold front is forecast to 
enter the NE pac waters by Thu morning. However, peak seas with 
this next event are expected to reach only 11-12 ft in NW swell 
across NE portions of the area.



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