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Eastern North Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 161602
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Fri Aug 16 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 
1545 UTC.

..TROPICAL WAVES AND TROPICAL LOWS...

A tropical wave is analyzed to the N of 05N along 81W. Scattered 
moderate and isolated strong convection is observed N of a line 
from 02N79W to 07N87W.  This wave has been progressing W at 
about 22 kts across the W Caribbean, but is expected to slow 
it's forward speed over the the next few days.  

A tropical wave is analyzed to the N of 07N along 102W and has 
moved W at 15 kt over the past 48 hours. Scattered moderate and 
isolated strong convection is observed within 120 of the wave 
axis. 

A surface low is analyzed at 11N107W and is estimated at 1008 
mb, and has moved W at 08 kt over the past 24 hours. Scattered 
moderate and isolated strong convection is currently observed 
within 120 nm of the low.

A 1008 mb surface low is analyzed within the monsoon trough at 
18N115.5W. Fresh to locally strong E to SE winds are observed 
within 180 nm over the NE semicircle of the low with seas of 6 
to 8 ft. The low is forecast to reach near 16N121W early Thu and 
near 16N126W early Fri with fresh to locally strong NE-E winds 
expected out about 180 nm over the N semicircle during the next 
48 hours.

The remnants of former tropical cyclone Jova continue to spin 
near 19N131W with a pressure of about 1009 mb. Isolated moderate 
to strong convection recently flared within 60 nm of 17N131W. 
The pressure gradient is supporting fresh N to NE winds and 6 to 
7 ft seas within 330 nm over the NW quadrant of the low. The low 
is forecast to move W-SW and weaken to an open trough by early 
Fri. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough extends W across the SW Caribbean from 09N78W 
to the Pacific coast of Costa Rica at 10N86W to 10N92W, then 
turns NW to a tropical wave at 12N102W, the continues NW to a 
surface low at 18N115.5W, then turns abruptly S to 14N120W, then 
turns W to beyond 13N140W. 

Except as previously mentioned, scattered moderate isolated 
strong convection is noted within 90 nm either side of a line
from 07N95W to 10.5N103W to 07N109W to 13.5N123W to 11N134W to
12.5N140W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A NW to SE orientated low level trough will meander E to W 
across the Baja California Peninsula and Gulf of California 
through Sun night with a surface low developing intermittently 
along the trough over the far northern Gulf of California 
waters. Currently the low has a surface pressure estimated at 
1007 mb resulting in fresh westerly winds along 30N. A NW to SE 
orientated ridge extends across the offshore waters from 23N116W 
to 20N106W. A gentle NW breeze is expected through Thu to the W 
of the Baja California Peninsula, except a moderate NW breeze 
forecast within 90 nm of the Baja coast, with combined seas of 3-
5 ft. Guidance suggests that the pressure gradient will tighten 
each evening with moderate NW flow W of Baja, except fresh NW 
flow within 90 nm of the Baja coast with 3 to 6 ft seas.

Gulf of California...gentle to locally moderate southerly flow 
will persist across the Gulf of California through the upcoming 
weekend, except a moderate to locally fresh breeze will surround 
the low pressure center over the waters N of 29.5N.

Gulf of Tehuantepec: light N drainage flow forecast tonight, 
then fresh to locally strong N winds expected during the 
overnight hours beginning on Thu night with seas building to 8 ft 
downstream of the gulf waters near 15N95W.

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

Gulf of Papagayo: moderate to locally fresh offshore winds 
expected tonight, then guidance suggest locally strong NE-E 
winds on Thu night, then guidance indicates that the pressure 
gradient through early Sun.

Light and variable to gentle NE to E flow expected N of the 
monsoon trough, while moderate southerly winds are expected S of 
the monsoon trough axis through the upcoming weekend with 3 to 6 
ft seas throughout.

REMAINDER OF THE AREA...

The subtropical ridge extends from 32N135W to near 23N116W. 
Except as previously mentioned in the tropical waves and 
tropical lows paragraph, moderate anticyclonic flow is forecast 
N of the monsoon trough and W of 125W. 

Long period southerly swell, in the form of 7 to 9 ft seas, is 
observed S of 06N between 100W and 125W. These seas will subside 
to less than 8 ft by midday on Thu.  

$$
Nelson

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Page last modified: Wednesday, 16-Aug-2017 16:02:47 UTC