000
AXPZ20 KNHC 152121
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Sat Jul 15 2023

Tropical Weather Discussion for the eastern Pacific Ocean from
03.4S to 30N, east of 120W including the Gulf of California, and
from the Equator to 30N, between 120W and 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
2100 UTC.

...SPECIAL FEATURES...

Hurricane Calvin is centered near 15.0N 130.4W at 15/2100 UTC
moving W at 14 kt. Estimated minimum central pressure is 975 mb.
Maximum sustained wind speed is 85 kt with gusts to 105 kt.
Numerous moderate to strong convection is noted within 60 nm of
center. Seas in excess of 12 ft seas extend within 180 nm N 
semicircle and 120 nm S semicircle with maximum seas estimated 
to reach 34 ft ft. Calvin is moving westward over open waters, 
and this general motion at a similar or slightly faster forward 
speed is expected during the next few days. Calvin is forecast to
cross 140W on Sun night into Mon morning. Weakening is forecast 
through early next week. Swells generated by Calvin are expected 
to begin reaching the Hawaiian Islands early next week. These 
swells are likely to cause life-threatening surf and rip current 
conditions. Interests in Hawaii should monitor the progress of 
Calvin.

Please read the latest HIGH SEAS FORECAST issued by National 
Hurricane Center at web-site 
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest 
Hurricane Calvin Forecast/Advisory and Public Advisory at 
www.hurricanes.gov for more details. 

...TROPICAL WAVE...

A tropical wave is along 84W/85W N of 04N, moving W at 10 to 15 
kt. The wave extends northward over central America and the NW 
Caribbean. Scattered moderate to isolated strong convection is 
noted near the southern end of the wave axis from 04N to 10N 
between 80W and 86W. Showers and thunderstorms are evident over
Central America near the wave axis.

A second tropical wave is along 106W N of 04N, moving W at 10 to
15 kt. A cluster of moderate to isolated strong convection is 
behind the wave axis from 12N to 16N between 100W and 105W. 
Scattered moderate to isolated strong convection is elsewhere 
along the wave axis. 

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

The monsoon trough extends from 10N84W to 09N95W to 10N106W to 
09N124W. The ITCZ stretches from 09N135W to 09N140W. A cluster of
moderate to strong convection is near the entrance to the Gulf 
of Panama. Scattered moderate to isolated strong convection is 
noted from 03N to 16N between 80W and 115W. 

...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A surface ridge dominates the offshore forecast waters of Baja 
California and extends SE beyond the Revillagigedo Islands. 
Gentle to moderate NW winds prevail with seas of 4 to 6 ft. Light
to gentle southerly winds are over the Gulf of California where 
seas are in the 1 to 3 ft range with the exception of 3 to 4 ft 
near the entrance to the Gulf. Moderate to fresh northerly winds 
prevail in the Tehuantepec region with seas of 4 to 6 ft. 
Elsewhere across the remainder of the Mexican offshore waters, 
light to gentle winds and seas of 4 to 5 ft in SW swell are 
noted.

For the forecast, the ridge will continue to dominate the offshore
forecast waters of Baja California through at least Tue generating
gentle to moderate NW winds with seas in the 4 to 5 ft range. 
Similar wind speeds are expected in the Gulf of California with 
seas of 3 ft or less. By Wed, winds and seas will increase some 
over the Gulf of California. At that time, moderate to fresh
southerly winds and seas of 3 to 5 ft are expected with the
highest seas over the northern part of the Gulf. Fresh to strong
northerly winds are forecast in the Tehuantepec region Mon through
Tue with seas building to 8 ft. This could be the result of a
developing low along the monsoon trough. 

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

Satellite derived wind data provide observations of fresh to 
strong NE to E winds across the Papagayo region and downwind to
about 89W. Seas are 5 to 7 ft within these winds. Light to gentle
winds and seas of 4 to 5 ft are noted over the remainder of the 
offshore waters north of 03N. Gentle to moderate southerly winds
are observed south of 03N where seas are 4 to 6 ft.

For the forecast, fresh to strong NE to E winds are forecast in 
the Papagayo region through the middle of the week with seas of 
5 to 7 ft. Light to gentle winds will dominate the remainder of 
the offshore forecast waters, with the exception of gentle to 
moderate southerly winds between Ecuador and the Galapagos 
Islands, and moderate to locally fresh NE to E winds across the 
offshore waters of Guatemala and El Salvador. Outside of the 
Papagayo region, seas of 4 to 5 ft in SW swell are expected.
However, seas generating in the Papagayo area will spread across
the offshore waters of Guatemala and El Salvador building seas 
to 5 to 7 ft.

...REMAINDER OF THE AREA...

Please see the SPECIAL FEATURES section above for more information
on Hurricane Calvin.

Aside from Calvin, a ridge prevails across the north waters anchored
by a 1025 mb high pressure center located N of the area near 
36N136W. Gentle to moderate winds are noted under the influence 
of the ridge. Wind and seas could be higher near the convective 
activity along the ITCZ/Monsoon Trough.

For the forecast, Hurricane Calvin will move to 15.6N 132.7W Sun
morning, 16.3N 135.8W Sun afternoon, weaken to a tropical storm 
near 16.8N 139.0W Mon morning, 17.3N 142.5W Mon afternoon, 17.7N 
146.2W Tue morning, and 18.3N 149.9W Tue afternoon. Calvin will 
change little in intensity as it moves to near 19.4N 156.8W Wed 
afternoon. Seas in excess of 8 ft generating by Calvin, will 
continue to propagate across the open waters, covering the area 
from 11N to 23N between 130W and 140W by Sun afternoon. An area
of fresh to strong E winds, with seas to 8 ft is forecast to
develop to the S and SW of the Tehunatepec region by Sun night
into Mon morning and could be associated with a developing low
pressure along the monsoon trough. 

Looking ahead, an area of low pressure could form well south of 
the coast of southwestern Mexico during the next several days. 
Some gradual development of this system is possible thereafter as
it moves generally west-northwestward over the central portion 
of the eastern Pacific basin. Refer to the latest NHC Tropical 
Weather Outlook at www.hurricanes.gov for more details.

$$
GR