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Eastern North Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 230241
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 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 0000 UTC surface analysis and satellite imagery through 
0200 UTC.

...SPECIAL FEATURES...

A broad elongated area of low pressure persists along the 
southwestern coast of Mexico and coastal waters, from Manzanillo 
to just south of the Gulf of Tehuantepec. A few weak cyclonic 
circulations are evident in satellite imagery within this broad 
area, with one near 17.5N104.5W, with an estimated pressure of 
1006 mb. Scattered moderate to strong convection is occurring NW 
of the weak low from 16.5N TO 21.5N between 104.5W and 108.5W. 
To the S of this low is a large area of fresh to locally strong 
SW monsoon winds, roughly from 10N to 13N between 103W and 115W. 
Model guidance indicates that this low pressure center occurring 
N of the zone of strong monsoonal flow has the potential to 
develop into a tropical cyclone as it drifts NW. The convergent 
monsoon winds will continue to generate widespread active 
convection along and near the coast of Mexico, with heavy rains 
likely to persist in this area several more days.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...         

The monsoon trough stretches across the entire basin from Panama 
near 08N74W TO 09N83.5W TO 14N92W TO low pres near 17.5N104.5W 
1006 MB TO 12N112W TO low pres near 14N137W 1010 MB TO beyond 
10N140W. Scattered moderate to strong convection is from 07N TO 
14N between 87W and 125W...AND from 08N TO 13N between 128W AND 
140W. 

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  

A weakening cold front extends from southern Arizona SW across 
the northern Gulf of California and Baja California Norte then 
WSW to beyond 24N126W. Afternoon scatterometer data showed fresh 
northerly winds behind the front across the offshore waters. 
Expect the front to push further south and weaken through early 
Sat, then dissipate by Sat afternoon. High pressure will build 
north of 25N behind the front through Sun, with NW winds 
increasing slightly west of Baja California Norte. Elsewhere, 
the possible development of low pressure along the southern 
coast of Mexico will increase winds and seas between 101W and 
115W the next few days. 

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

An active monsoon trough meandering 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 gradually become 20-25 
knots through Saturday. 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 
maintain seas west of Ecuador and south of 01N around 7-8 ft 
through Sat morning. 

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 25N between 114W and 
122W. This area of combined seas will slowly subside during the 
next 24 hours. High pressure centered well N of the area and 
lower pressure associated with the monsoon trough will maintain 
moderate to occasionally fresh trade winds west of 120W through 
the weekend.

$$
Stripling

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Page last modified: Saturday, 23-Sep-2017 02:42:53 UTC