Home


000
AXPZ20 KNHC 200202
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Fri Oct 20 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 0000 UTC surface analysis and satellite imagery through 0430 UTC.


...TROPICAL WAVES...

A tropical wave is N of 04N near 90W moving slowly W around 5 kt. Scattered moderate and isolated strong convection is noted from 06N to 08N between 89W and 92W.


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

The monsoon trough extends from 10N82W to 09N121W. The ITCZ continues from 09N121W to beyond 10N140W. Scattered moderate convection exists within 60 nm of the trough from 93W to 98W. Scattered moderate and isolated strong convection is occurring within 60 nm of the ITCZ west of 138W.


...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

High surface pressure over the Gulf of Mexico along with lower pressure along the Pacific monsoon trough have been forcing gap wind flow though the Chivela Pass in southeastern Mexico. This has been producing a Gulf of Tehuantepec gap wind event, which has weakened to near gale conditions, though no new observations have been available recently, and peak seas near 8 ft. Forcing for this gap wind event will gradually fade and drop to winds 20 kt or lower and seas less than 8 ft by Saturday afternoon.

The next cold front pushing across the Gulf of Mexico on Sunday will initiate the next Tehuantepecer wind event. This is likely to reach gale force on Monday through Wednesday and may approach storm force on Wednesday.

A cold front has reached the northwest corner of our region at 30N140W. As the front approaches the Baja California peninsula on Friday, winds along the northwest coast will reach strong breeze out of the northwest Friday morning and continue only through Saturday afternoon. While winds associated with the cold front will quickly diminish, large 12 to 16 ft NW swell will be reaching the zones along the northwest coast of the Baja California peninsula starting Friday night. These swell are the result of a large and powerful low pressure system along the Alaska coastline. This large 15-20 second period swell will reach the zones near the southwestern coast of the Baja California peninsula on Saturday and then drop below 12 ft late Sunday. 8 to 12 ft NW swell will reach the zones near southwestern Mexico by early Sunday and fade by late Monday.

As high pressure builds in over the U.S. Great Basin, N to NW winds will set up over the Gulf of California from Sunday through Tuesday. Currently, these are forecast to reach strong breeze conditions, though near gale are certainly possible. Accordingly, wind waves from the long fetch of N to NW winds blowing lengthwise through the Gulf of California are anticipated to reach up to 8 ft.

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

No winds of strong breeze or greater are expected in the area for the next several days. Tonight, seas of 8 ft will be reaching the southernmost zones from a combined SE and S swell. This will diminish by early Saturday.

REMAINDER OF THE AREA...

A cold front has reached the northwest corner of our region at 30N140w. As the front approaches the Baja California peninsula on Friday, winds along the northwest coast will reach strong breeze out of the northwest Friday morning and continue only through Saturday afternoon. Elsewhere winds associated with the front will remain at 20 kt or less. Rapidly building seas associated with long-period 15-20 second swell have approached the northwestern corner of our region, as observed by a 23Z altimeter pass. These seas will reach 12 to 16 ft and are the result of a large and powerful low pressure system along the Alaska coastline. The swell will push southeastward across most of the region, while gradually diminishing over the next few days. Peaks seas will drop below 12 ft Sunday afternoon and the 8 ft swell will finally diminish by Wednesday.

The tradewinds are fresh breeze and weaker across the remainder of the areas. These should remain weak for the next several days.

No tropical cyclone formation is anticipated over the next several days.

$$ Forecaster Landsea

Home