000
AXPZ20 KNHC 090237 CCA
TWDEP 

Tropical Weather Discussion...corrected
NWS National Hurricane Center Miami FL
2205 UTC Thu Jun 8 2017

corrected Tropical Lows and Waves section

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
2145 UTC.

...TROPICAL LOWS AND WAVES...

A tropical wave axis is along 112W from 05N to 14N, moving west 
at 10 to 15 kt. This wave is moving into a more dry and stable 
environment. Only a small area of scattered moderate convection 
is noted within 120 nm west of the axis from 07N to 10N. 
Isolated weak showers and thunderstorms are east of the wave 
within 30 nm of 08N108W.

A weak 1012 mb surface low is analyzed near 09N129W with a 
trough extending north-northeast to near 14N127W. Satellite water
vapor shows sharp upper trough axis just to the northwest of the
low. Strong southwest winds associated with this trough are 
shearing away and deep convection that attempts to develop in the
vicinity of the low. The southwest winds are advecting upper 
level moisture, in the form of scattered to broken high clouds, 
from earlier convection that was near the low north-northeast to
just west of the southern Baja California peninsula.

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

A weak Monsoon Trough axis extends from a 1008 mb low located 
over NW Colombia to northern Costa Rica and Panama to offshore
northern Costa Rica at 11N85W west to 11N95W and to 12N103W.
A more defined monsoon trough is then analyzed from 10N106W to 
07N115W, where scatterometer winds indicate that the ITCZ forms 
and extends northwestward through an embedded 1012 mb surface 
low at 10N129W, then continues westward to beyond 08N140W. 
Scattered moderate isolated strong convection is observed within
60 nm of the axis between 97W and 101W. Scattered moderate 
convection is within 60 nm north of the axis between 111W and 
114W. 

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A northwest to southeast orientated ridge extends across the 
waters just west of the offshore zones, with the associated 
pressure gradient maintaining light to locally moderate northwest
winds west of the Baja California peninsula north of 25N, and
moderate to fresh west to northwest winds south of 25N. An 
Ascat pass from 1724Z highlighted a small area of strong west 
to northwest winds along and within about 60 nm of the coast 
of Cabo San Lucas. The pressure gradient will tighten on Friday
with moderate to locally fresh northwest winds developing to the
north of 25N. Another round of large nw swell in the form of 7 
to 10 ft seas will arrive along 32N on Sunday, then propagate 
southward to along 30N by late on Sunday night. Wave model 
guidance suggests that this swell will reach south to near 27N 
on Mon evening before it begins to decay.

Gulf of California: Gentle to moderate southerly flow is expected
north of 30N through Sat, then fresh to locally strong southwest
winds are forecast from 30N to 31N beginning on Saturday, with 
seas building to about 5 ft. Light and variable winds are 
expected s of 30N through Mon night.
 
Gulf of Tehuantepec: Moderate northerly drainage will briefly 
increase to fresh winds late tonight into Friday, then become
light to gentle variable winds Friday afternoon.

Mexican offshore waters elsewhere s of 23N: light to gentle west 
to northwest winds are expected, except for southeast to south 
winds near the coast and 3 to 5 seas are forecast through Mon 
night.

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

Gentle to moderate westerly winds and 4 to 6 ft seas are 
expected n of 08N, and moderate to fresh southerly winds with 5 
to 7 ft seas forecast s of 08N through early Friday. Light to 
moderate southerly flow and 3 to 6 ft seas, then forecast 
through Mon night.  

REMAINDER OF THE AREA...
  
A 1021 mb surface high is analyzed at 27N126W with a ridge 
extending southeastward to near 11N110W. Gentle to locally 
moderate anticyclonic flow is observed south of the ridge to 
along 10N. Moderate to fresh southwest flow is present to
the north of the surface high, and also to the east of a weak 
cold front analyzed from near near from 32N130W to 28N140W. 
Gentle to moderate northerly flow is occurring to the northwest
of the front. The front will lose its upper level support as 
broad upper troughing north of the area slides eastward. As a
result, the front is forecast to become stationary from near 
32N120W to 25N140W on Fri night and gradually wash out through 
Sat night as a stronger area of high pressure builds
southeastward over the northwest and central portions of 
the discussion area.

$$

Aguirre