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Eastern North Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 230935
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
626 UTC Sat Sep 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.

...SPECIAL FEATURES...

A broad elongated area of low pressure remains in place along 
the southwestern coast of Mexico and adjacent coastal waters, 
from Manzanillo to just south of the Gulf of Tehuantepec. The 
latest satellite-derived wind data indicated this area of low 
pressure remains weak and winds in the vicinity of the 
circulation are 20 kt or less. However, the latest IR satellite 
imagery shows deep convection has flared during the past several 
hours on the west side of the circulation, which is centered near
17.5N104.5W, with an estimated pressure of 1007 mb. To the S of 
the low and detached from it is a large belt of fresh to locally 
strong SW monsoon winds, roughly from 10N to 14N between 100W and
120W. Model guidance indicates that the low retains the 
potential to develop into a tropical cyclone as it slowly drifts 
NW. toward the southern Gulf of California. The convergent 
monsoonal winds will continue to generate widespread active 
convection along and near the coast of Mexico and Central 
America, with heavy rains likely to persist in this area at least
several more days.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...         

The monsoon trough stretches across the entire basin and extends
from northern Colombia near 10N74W to just north of Panama near 
11N77W to Costa Rica near 09N84W to the Gulf of Tehuantepec near 
16N95W to low pres 1007 mb near 18N105W to 12N126W to low pres 
1011 mb near 14N137W to beyond 11N140W. Scattered moderate and 
isolated strong convection is found along and up to 180 nm SW of 
the trough axis between 90W and 96W and from 10N to 12N between 
129W and 134W. Scattered moderate convection is present within 90
nm either side of a line from 13N98W to 11N120W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  

A weakening cold front extends from SE Arizona SW across the 
central Gulf of California and northern Baja California Sur, 
then WSW to beyond 24N117W. Latest satellite-derived wind data 
showed moderate to fresh NNW winds behind the front over the 
offshore waters. Expect the front to push farther south and 
dissipate by this evening. High pressure will build north of 25N 
behind the front through Sun, with NW winds increasing slightly 
west of Baja California Norte. Elsewhere, the expected 
development of low pressure along the coast of Mexico south of 
Cabo Corrientes will increase winds and seas from Cabo Corrientes
to the southern Gulf of California during the next few days.

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

An active monsoon trough undulating along the coast of Central 
America from Guatemala to Panama will remain the focus for active
convection over the coastal waters the next few days. Expect SW 
winds south of the trough to increase from moderate to fresh 
speeds during the next few days. Farther south, gentle to 
moderate south to southwest winds will persist south of 05N 
through the weekend. Long period SE swell from the Southern 
Hemisphere will remain high enough to maintain seas west of 
Ecuador and south of the Equator around 7-8 ft through this 
evening.

REMAINDER OF THE AREA...

NW swell generated by strong N to NW winds north of the area are
producing combined seas to 8 ft north of 28N between 116W and 
123W. This area of combined seas will subside around 1 foot 
during the next 24 hours. High pressure centered well N of the 
area and lower pressure associated with the monsoon trough will 
combine to maintain moderate to occasionally fresh trade winds 
west of 120W through Mon. Low pressure passing north of the area 
will weaken the high and cause the trades to decrease during the 
second half of next week.

$$
CAM

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Page last modified: Saturday, 23-Sep-2017 09:36:31 UTC