000
AXPZ20 KNHC 192212 CCA
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL 
2205 UTC TUE SEP 19 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 
2115 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION NORMA NEAR 21.9N 115.0W 1006 MB AT 2100 UTC 
SEP 19 MOVING WNW OR 290 DEG AT 6 KT. MAXIMUM SUSTAINED WINDS 30 
KT GUSTS 40 KT. WIDELY SCATTERED MODERATE CONVECTION IS NOTED 
WITHIN 45 NM NW AND 75 NM SE SEMICIRCLES. Norma is expected to 
move slowly NW and gradually lose tropical characteristics in 
the next 24 hours as it moves over cooler waters and into more 
stable atmospheric conditions. Associated winds and seas will 
slowly wind down during the next 2 days before the low 
dissipates Thu.

POST-TROPICAL CYCLONE OTIS NEAR 18.6N 128.7W 1008 MB MOVING WSW 
AT 5 KT. MAXIMUM SUSTAINED WINDS 30 KT GUSTS 40 KT. No 
convection is associated with the remnants of Otis at this time. 
However, sufficient pressure gradient exists between this low 
center and a surface ridge to the NW to create strong NE to E 
winds 20 to 30 kt WITHIN 180 NM across the NW SEMICIRCLE, where 
seas are 8 to 12 ft. The low will continue to move WSW during 
the next 2 days and gradually dissipate, with an area of fresh 
to strong NE to E winds and seas 8 to 9 ft accompanying it 
through Thu. 

...TROPICAL WAVES...

A tropical wave is propagating across the eastern Pacific Ocean 
just to the west of the Gulf of Tehuantepec, along 95-96W N of 
07N. Scattered moderate to strong convection is from 10N to 16N 
between 92W and 104W. Global models suggest that a low pressure 
center could develop across this region in a few days.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...         

Monsoon trough extends from 10N85W to 13N100W to 12N120W to 
13N140W. Scattered moderate convection is from 03N to 08N 
between 77W and 84W. Scattered moderate to strong convection is 
from 07N to 12N between 87W and 91W. Scattered moderate to 
strong convection is from 12N to 16N W of 132W.  

...DISCUSSION...   

To the North of 15N and to the east of 120W:  

A broad surface ridge extends SE into the region and passes 
through 32N128W to near 25N118W. Anticyclonic wind flow covers 
the area N through NW of the lows of Norma and Otis. A surface 
trough is in the northernmost part of the Gulf of California, 
where fresh northerly winds prevail across the nearshore waters 
of Baja California Norte. The surface pressure gradient that 
exists between the ridge and the trough is supporting gentle to 
moderate N to NE winds, and seas in the range from 5 feet to 7 
feet. The ridge will continue to build during the next few days, 
which will freshen winds off the Baja California coast with seas 
building to 6 to 8 feet.

To the South of 15N and to the east of 120W:

A tropical wave across the W Caribbean is moving into the far 
eastern waters. Light to gentle monsoonal flow prevails to the 
south of the monsoon trough, while gentle to moderate 
southeasterly trade winds prevail to the south of the monsoon 
trough. Light to gentle northeasterly trade winds prevail to the 
north of the monsoon trough for the next few days. Southwesterly 
swell continues to propagate across the area with seas in the 6 
to 8 foot range from 100W westward, and in the 4 to 6 foot range 
from 100W eastward.

Elsewhere to the west of 120W:

A 1031 mb high pressure center is located near 38N149W and 
extends S and SE into the waters N of 25N. The surface pressure 
gradient that exists between this high pressure, and the lower 
pressure that is in the vicinity of the monsoon trough, will 
maintain moderate to fresh trade winds to the N of 21N west of 
130W, with sea heights in the 8 foot to 10 foot range. The ridge 
will prevail in the northern waters during the next few of days 
with these general conditions persisting. 

$$
Stripling