axpz20 knhc 221609
Tropical weather discussion
NWS National Hurricane Center Miami FL
1605 UTC Wed may 22 2013
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
Based on 1200 UTC surface analysis and satellite imagery through
...Intertropical convergence zone/monsoon trough...
Monsoon trough axis extends from SW Caribbean near 11n82w to
12.5n90w to 13n100w to 09.5n115w...where it transitions to
ITCZ...continuing on to 07.5n123w to 11.5n131w to 03.5n140w.
Scattered to locally numerous moderate to strong convection
noted within 120 nm N and 210 nm S of trough axis between 98w
and 103w. Scattered moderate isolated strong convection noted
within 150 nm N and 90 nm S of axis between 113w and 120w.
Scattered moderate to strong convection noted within 120 nm N of
ITCZ between 128w and 135w.
A surface ridge dominates W and NW portions of the area this
morning...anchored on a 1036 mb high centered near 44n143w with
ridge extending se to near 18n116w. A strong pres gradient along
the coast of California is producing gale force N-NW
winds...with 20-25 kt winds extending S into the discussion area
N of 28n between 119w and 132w...where seas are running 8 to 10
ft. Satellite imagery this morning also depicts the elongated
remnants of former T.S. Alvin embedded along the ITCZ in the
vicinity of 134w. The pres gradient between the ridge and this
low pressure are producing a small area of NE winds 20-25 kt
from roughly 12n to 16n between 129w and 136w...where seas are 8
to 10 ft. Otherwise...moderate to fresh anticyclonic flow
prevails across the area W of 120w...with seas generally 7 to 8
ft in mixed northerly and SW cross equatorial swell. The high is
forecast to sink S during the next few days with northerly winds
20-25 kt pushing a bit farther S into the area to 27.5n between
118.5w and 126w by Friday morning. N-NW to N swell generated
offshore of California will continue to propagate southward
across the regional waters through the weekend...peaking at 12
to 15 ft offshore of Baja California norte Thursday morning.
Meanwhile...the remnants of Alvin will continue to shift wwd
through the weekend and maintain a modest area of NE winds 20-25
kt and seas 8-9 ft within 180 nm to the NW.
Monsoonal flow has become well established across the far
eastern Pacific E of 110w...with moderate SW to W winds
extending as far N as 11n between 95w and 110w. Upper level
ridging prevails across the area E of 110w and is producing a
favorable environment for sustained deep convection.
A broad low to middle level cyclonic circulation is forecast to
develop along 80w-82w...straddling Central America and
extending into both the SW Caribbean and the epac. Global models
forecast this feature to shift W during the next several days
with some potential for improved organization and gradual
intensification. Freshening gap wind flow through the gulfs of
papagayo and Tehuantepec beginning Saturday will flow across the
N and into portions of this westward moving feature...and could
contribute to barotropic growth and intensification. Freshening
winds to 25 kt are expected downstream of papagayo by early
Sunday...at which time northerly flow is expected to begin to
freshen through the Gulf of Tehuantepec.
Note...a GOES-E/GOES-13 anomaly occurred last night prior to
0400 UTC and has impacted the full suite of imagery available
from this satellite...and is limiting confidence in satellite
interpretation across the region between approximately 60w and
100w. NESDIS engineers are working on recovery efforts at this
time. GOES-14 is being activated and the first images are
expected to become available around 0500 UTC Thu may 23.