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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 222206
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Fri Sep 22 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 1800 UTC surface analysis and satellite imagery through 
2100 UTC.

...SPECIAL FEATURES...

A broad elongated area of low pressure persists along the 
southern coast of Mexico and coastal waters, from Manzanillo to 
Puerto Angel. A weak cyclonic circulation is evident in 
satellite imagery within this broad area near 17N104W, with an 
estimated pressure of 1007 mb. Scattered moderate to strong 
convection is occurring NW of the weak low from 16.5N to 23N 
between 105W and 107.5W. To the S of this low is a large area of 
fresh to locally strong SW monsoon winds, roughly from 10N to 
14N between 98W and 117W. 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 07N73.5W TO 09N83W TO low pres near 17N104W 1007 MB TO 
13.5N117W TO 12.5N130W TO beyond 10N140W. Scattered moderate to 
strong convection is from 05N to 08.5N between 77.5W and 
84W...within 90 nm N and 240 nm S of the trough between 87W and 
100W...and within 120 nm S of the through between 105W and 131W. 

...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 25N126W. 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 
117W 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 02S 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 29N between 118W 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