AXPZ20 KNHC 041551
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Tue Aug 4 2020
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
A tropical wave has its axis along 117W from 02N to 17N, moving
westward at about 15 kt. Small isolated showers and thunderstorms
are within 120 nm either side of the wave axis from 07N to 15N.
The wave is well depicted in the 700 GFS streamline guidance.
A tropical wave has its axis along 125W/126W from 02N to 17N,
moving westward at 15-20 kt. This wave remains embedded within a
very moist and unstable environment. Satellite imagery indicates
that a mid-level cyclonic circulation trails this wave along the
monsoon trough axis near 12N121W. Scattered moderate to isolated
strong convection is seen within 240 nm east of the wave axis
from 13N to 17N. Scattered moderate convection is east of the
wave axis within 60 nm of 09N125W. Scattered showers and isolated
thunderstorms related to the mid-level cyclonic circulation are
noted from 09N to 13N between 118W-123W.
A tropical wave has its axis along 139W from 02N to 16N, moving
westward at 15-20 kt. Moisture associated with this wave remains
confined to along and near the monsoon trough axis within 180 nm
east of the wave axis. This is also where the total precipitable
water imagery animation (TPW) shows a deep pocket of moisture
and where scattered moderate convection is occurring. Similar
convection is east of the wave axis within 30 nm of a line from
10N133W to 11N136W. This tropical wave is indicated pretty well
in the GFS 700 mb streamline guidance.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough axis extends from a 1011 m low that is along
the coast of Colombia near 11N75W west-southwestward to across
the Costa Rica/Panamanian border to 09N84W and northwestward to
10N96W to 12N104W to 12N117W and southwestward to 10N129W and to
10N140W. Clusters of scattered moderate to strong convection are
within 300 nm north and 120 nm south of the trough axis between
94W-98W. Scattered moderate to isolated strong convection is
from 05N to 08N between 78W-80W, also within 120 nm south of the
trough axis between 84W-87W, within 120 nm either side of the
trough axis between 89W-94W and within 30 nm of the trough axis
between 98W-104W. Scattered moderate convection is within 60 nm
north of the trough axis between 133W-135W and within 30 nm of
the trough axis between 107W-113W and west of 135W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
A 1029 mb high pressure center is analyzed well to the northwest
of the discussion area at 37N149W, with its associated ridging
extending southeastward to 32N137W and to near 23N124W. The
pressure gradient between this system and a meandering trough
over the Baja California Peninsula will support moderate to fresh
northwest to north winds to the west of Baja California, and
mainly N of Cabo San Lazaro Wed night through Sat night along
with seas building to 6-8 ft.
During this time of the year, the prevailing winds in the Gulf
of California are mainly southeast in direction. Gentle to
moderate southeast to south winds are expected in the northern
and central parts of the Gulf well into the middle part of the
week, while mainly gentle southeast to south winds are forecast
elsewhere, including the entrance to the Gulf. Seas will range
from 3-4 ft, except up to 5 ft near the entrance to the Gulf.
Overnight ASCAT data revealed northerly winds of 20-25 kt across
the Gulf of Tehuantepec. Winds of this speed range are expected
to continue to pulse across the Tehuantepec region through Thu,
mainly during the overnight and early morning hours with the
assistance of the nocturnal drainage flow. Seas with these
pulsing winds will briefly build to 8 ft. Winds are expected to
increase again across this area during the upcoming weekend.
Latest wind and wave height model guidance is suggesting
stronger winds, possibly reaching to near gale force, along with
higher resultant seas.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and
WITHIN 750 NM OF ECUADOR...
A monsoon trough axis meanders roughly from 09N to 10N east of
about 100W. Overnight ASCAT data revealed mainly moderate south
to southwest winds to the south of the monsoon trough, and light
and variable winds to the north of the monsoon trough.
As it is normal for this time of the year, tropical waves will
continue to migrate westward from the Caribbean Sea to across
Central America into the eastern Pacific region, helping to
induce convective activity across the area. Presently, three
tropical waves are moving westward to the west of 110W. Another
tropical wave is forecast to move into the far eastern part of
the area near 85W by Wed and reach to near 91W on Thu. Global
model guidance suggests that this wave may have potential for
tropical cyclone development across the eastern Pacific several
days from today.
REMAINDER OF THE AREA...
As previously mentioned, a 1029 mb high pressure center is
situated well to the northwest of the area. The gradient between
is associated ridging that extends southeastward across the
northern waters and lower pressure in the tropics near and along
the monsoon trough will allow for moderate to fresh trade winds
to exist from 12N to 26N and west of 125W through the rest of the
week. Seas with these winds are expected to be in the 5-7 ft
Long-period cross-equatorial southerly swell producing seas of
7-8 ft is forecast to reach near 01N and the offshore waters of
the Galapagos Islands during Fri.