AXPZ20 KNHC 240915
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Mon Sep 24 2018
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 0600 UTC surface analysis and satellite imagery through
A broad area of low pressure is analyzed as 1009 mb surface low
near 13.5N 102.5W. Scattered moderate isolated strong convection
is observed within 90 nm south of the low with intermittent
banding features. The associated tightening pressure gradient
will increase the southwesterly monsoonal flow to a fresh to
locally strong breeze well south of the low, across the tropical
waters from 06N to 12N between 178W and 116W over the next 24
hours. Environmental conditions are very favorable for tropical
formation as this low tracks west-northwest over the next few
days. Much uncertainty at this time, but for now expect fresh to
strong easterly winds, and building seas, to spread north across
the offshore waters from 16.5N to 23N on Wed through Sat, with
southerly swell, in the form of 8 to 12 ft seas, to propagate
north across the waters west of the Baja Peninsula during the
upcoming weekend. Refer to the East pacific tropical Weather
Outlook under WMO/AWIPS headers ABPZ20 KMIA/MIATWOEP for
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends W off the Caribbean coast of Colombia
at 09N76W, and continues west across the extreme southwest
Caribbean to the Pacific coast of Costa Rica at 10N86W through a
tropical wave along 10N94.5W, then turns northwest through the
surface low at 13.5N 102.5W, then turns southwest to 12N109w to
to 13.5n116.5W to 10N140W. Scattered moderate isolated strong
convection is observed across the gulfs of Panama and
Tehuantepec and within 75 nm of 20N106W. Isolated moderate and
strong convection is noted elsewhere within 270 nm either side
of a line from 05N82W to 13N98W, and from 07N to 17N
between 98W and 137W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
See the Special Features paragraph above. A ridge extending from
22N116W to 20N108W will gradually retract north during the
middle of the week as a surface low, possibly a tropical
cyclone, tracks northerly beyond 250 nm seaward. Gentle
northwest flow is forecast west of the Baja California through
mid week, except becoming a moderate northwest breeze within 90
nm of the coast during the late afternoons and evenings.
Gulf of California: Gentle to locally moderate variable winds
forecast across the gulf waters north of 30N through this
evening. Otherwise, light to gentle variable winds expected
across the gulf waters through the middle of the week.
Gulf of Tehuantepec: Strong northerly flow forecast through late
this afternoon, then fresh to locally strong nocturnal drainage
forecast to resume tonight with a strong event expected on
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Gulf of Papagayo: Moderate to locally fresh east nocturnal
drainage flow expected through Thu night with seas building to
Light and variable winds are forecast elsewhere north of the
monsoon trough which is meandering between 09N and 12N. Moderate
southwest flow is forecast south of the monsoon trough.
REMAINDER OF THE AREA...
See the Special Features paragraph above. A broad ridge
continues across the subtropics accompanied by moderate to
locally fresh anticyclonic flow south of 23N west of 120W.