AXPZ20 KNHC 212121
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Wed Apr 21 2021
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 1800 UTC surface analysis and satellite imagery through
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from northern Colombia near 10N74W to
08N90W to 09N105W to 07N114W. The ITCZ axis continues from 07N114W
to 06N130W to 05N140W. Scattered moderate isolated strong convection
is noted from 02N-06N between 78W-90W, from 04N-09N between 98W-117W,
from 04N-10N between 120W-132W, and from 03N-06N W of 132W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
A ridge dominates the offshore waters west of Baja California,
producing moderate NW to N winds across the area. Seas are 5 to 6
ft across most of the forecast region, except 6-8 ft in NW swell
north of Punta Eugenia. Long period southerly swell will reach
the waters W of Baja California on Thu and combine with NW swell
to build seas to 6-7 ft across most of that region.
Gulf of California: Fresh S to SW winds spilling into the northern
part of the Gulf this afternoon are expected to increase to 25-30
kt during the late afternoon and evening hours. Seas will increase
to 5-7 ft during that time. A recent scatterometer pass indicated
fresh S to SW winds N of 29N. Moderate to fresh southerly winds
are expected over the northern Gulf through Thu night, with gentle
to moderate winds elsewhere across the region.
Gulf of Tehunatepec: A weak low pressure spinning over the SW
Gulf of Mexico supports a northerly gap wind event across the
Tehuantepec region. Winds are forecast to increase to 20 to 30
kt tonight, with seas building to 11 ft downstream of the Gulf
to near 13N by early Thu morning.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and
WITHIN 750 NM OF ECUADOR...
High pressure building over the NW Caribbean will support fresh
to strong winds across the Papagayo area this evening through Fri
morning, with associated seas building to 8-9 ft by Thu. Light
to gentle winds will prevail elsewhere through Sun. Large, long
period cross-equatorial southerly swell will build seas to 8 ft
across the waters between Ecuador and the Galapagos Islands
through late Thu.
REMAINDER OF THE AREA...
The pressure gradient between strong high pressure well north of
the forecast area and lower pressures in the vicinity of the
ITCZ supports a large area of moderate to fresh trade winds from
08N to 30N W of 125W based on latest scatterometer data. Seas
are 7 to 8 ft across this region. High pressure will gradually
weaken during the next 24-48 hours as a cold front approaches
from the west. Northerly swell will propagate across the waters
north of 28N between 118W and 131W through late Thu, building
seas in the northern waters to 8-9 ft. Seas will subside to less
than 8 ft Thu night and Fri.