000
AXPZ20 KNHC 050928
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Fri May 5 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 0600 UTC surface analysis and satellite imagery through 
0900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning...High pressure building behind 
a strong late season cold front moving across the Gulf of Mexico 
has induced minimal gale force northerly winds funneling into 
the Gulf of Tehuantepec. ASCAT scatterometer data at 0317 UTC 
showed a small area of 35 kt winds north of 15.5N between 94.5W 
and 95W. This area of gales will expand this morning with seas 
building to 13-14 ft later today. Gale force winds will persist 
through sunrise Saturday then become fresh to strong Saturday 
evening. Maximum seas will gradually subside to less than 8 ft 
by Sunday morning.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
         
A surface trough axis extends from 08N78W to 11N92W to 09N105W. 
The ITCZ extends from 09N106W to 04N140W. Scattered moderate to 
isolated strong convection is noted from 03N to 06N east of 92W, 
and from 09N to 14N between 90W and 98W. Scattered moderate 
convection is evident within 90 nm either side of the ITCZ axis 
between 106W and 119W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

See the special features section for information on the Gulf of 
Tehuantepec gale warning.

Mainly light to moderate NW winds and combined seas of 5-7 ft 
will prevail across the waters NW of Cabo Corrientes this 
morning, with light to moderate W to SW winds prevailing east of 
Cabo Corrientes to Puerto Angel. Light and variable winds 
currently prevail in the Gulf of California, with seas 2 ft or 
less except up to 4 ft south of 24N.

A cold front will approach the SW United States and NW Mexico 
this evening, then move across NW Mexico tonight through Sunday. 
Winds will increase across the Pacific waters of Baja California 
through Saturday night ahead of the front, then become fresh to 
near gale force in the northern Gulf of California ahead of the 
front late tonight into early Saturday. Behind the front, fresh 
to strong winds are forecast offshore of Baja California Norte 
and in the northern Gulf of California. Seas will build to 8-12 
ft in N swell in Pacific waters north of 22N west of the front 
through early next week. Seas will build to 5-8 ft north of 29N 
in the Gulf of California tonight through Saturday night.

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

Light to gentle SW to W winds prevail S of 10N this morning, 
while gentle to moderate E to NE winds are occurring N of 10N. 
Only minor fluctuations in winds are expected across the area 
through Saturday, before some uncertainty in the forecast arises 
Sunday through the middle of next week. Seas will remain mainly 
4-6 ft in SW swell. 

Looking ahead, global models continue to indicate an elongated 
cyclonic circulation is likely to develop and extend across the 
region. This may be the early onset of monsoon season. Global 
models also indicate upper atmospheric conditions will become 
very conducive for sustained deep convection this weekend 
through the middle of next week across central America and the 
adjacent offshore waters to portions of far southeastern Mexico. 
The models are not in good agreement in the development of a low 
pressure system within the larger elongated gyre, but do suggest 
that a surface low or two will eventually develop across the 
tropical eastern Pacific between Central America and 95W by the 
middle of next week. Slow movement of this low pressure area 
could lead to very heavy rainfall across portions of the region 
from Costa Rica NW toward SW Guatemala. 

REMAINDER OF THE AREA...

A cold front in the NW part of the discussion area extends from 
30N138W TO 29N140W. Fresh to strong northerly winds will trail 
behind the front as it moves eastward and stronger high pressure 
builds in its wake. Large NW swell to 12 ft will also accompany 
the front with 8 ft or greater seas likely to cover much of the 
area of 20N west of 120W this weekend. Moderate to fresh trades 
will cover this area for the early part of next week along with 
combined seas of 5-8 ft, except 8-14 ft seas over the NE portion 
due to stronger winds north of the area off southern California.

$$
Mundell