000
AXPZ20 KNHC 201537
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL 
1605 UTC Wed Sep 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 1200 UTC surface analysis and satellite imagery through 
1500 UTC.

...TROPICAL WAVES...

A tropical wave along 97W N OF 10N is moving west at 10 kt. 
Satellite imagery indicates a weak low is along the wave axis 
near 14N97W. Scattered moderate isolated strong convection is 
from 13N to 17N between 95W and 101W. Global models suggest that 
environmental conditions are favorable for the low to develop S 
of Mexico the next few days as it moves further west.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...         

The monsoon trough stretches across the entire basin from the 
coast of Panama near 09N79W to 14N96W to 11N110W to 11N126W to 
13N140W. Scattered moderate isolated strong convection is from 
09N to 11N between 89W and 102W, and in a small area within 45 
nm of 07N79W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...  

A weak surface ridge reaches the central part of Baja California 
near 27N. Low pressure over southern Arizona and an approaching 
cold front pushing southward along the coast of California will 
induce fresh to strong SW winds in the northern part of the Gulf 
of California tonight through early Fri morning, with max seas 
building to 5-6 ft north of 30N. The local effects will be less 
evident west of Baja California and south of 29N in the Gulf of 
California. Elsewhere, the possible development of low pressure 
along the tropical wave currently near 14N97W expected to move W 
to near 16N103W through Fri will increase winds and seas south 
of the Mexican coast between 97W and 105W the next few days. 

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

A fairly active monsoon trough along the coast of Central 
America from Guatemala to Panama will increase convective 
activity in coastal waters the next few days. Expect SW winds 
south of the trough axis to gradually strengthen to 10-15 kt and 
become more westerly by Fri. Further south, gentle to moderate 
southerly winds are expected to persist south of 05N through the 
weekend. S to SW swell continues to propagate across the area 
with seas in the 4 to 6 foot range east of 100W.

REMAINDER OF THE AREA...

Post-tropical remnant low Norma 1008 mb near 22N117W maintains a 
disorganized swirl of low clouds and stratiform convection, with 
winds estimated to be 20-25 kt NW of the center and seas to 9 
ft. The low will move slowly W to NW and weaken through Friday.

Post-tropical remnant low Otis 1009 mb near 17N130W maintains a 
swirl of multilayered clouds and stratiform convection. Fresh to 
strong N-NE winds and 8-10 ft seas are with 120 nm NW of the low 
center. The low is expected to drift SW and weaken into a trough 
through Friday, with seas gradually diminishing to 6-7 ft.

NW swell associated with strong N-NW winds north of the area is 
producing combined seas of 8-9 ft north of a line from 30N120W 
to 26N140W. This area of 8-9 ft seas is expected to contract and 
shift slightly eastward through Thu night. Another weaker round 
of NW swell associated with a cold front west of California is 
expected to arrive Fri night. High pressure centered well N of 
the area and lower pressure associated with the convergence zone 
will maintain moderate trade winds across most of the remainder 
of the area through the weekend. 

$$
Mundell