AXPZ20 KNHC 202124

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Fri May 20 2022

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 2030 UTC.


A broad area of low pressure, known as the Central American Gyre (CAG), has formed across Central America and the adjacent western Caribbean today, and is forecast to shift west to northwestward over the next several days. This feature will enhance the existing SW monsoon flow, lift the monsoon trough northward across Central America, and transport abundant moisture northward. In response, convection is expected to become more widespread, starting today, over the southern portions of Central America, and then gradually shift north and northwestward across northern portions of Central America and adjacent waters. There will be the potential for locally heavy rainfall near the Pacific coast of Central America, and also the eastern parts of Honduras and Nicaragua. Flash flooding and mudslides will be possible in areas that receive the heaviest rainfall. Please refer to products issued by your local weather service for more information.


A tropical wave extends southward from Belize along 89W across portions of Guatemala, Honduras and El Salvador, and into the eastern Pacific to near 04W. Associated convection described below, has become scattered over land and behind the wave this afternoon, affecting interior portions of Panama, Costa Rica, Nicaragua and Honduras.


The monsoon trough extends from 11N74W to 13N92W to 11N117W to 08N129W. The ITCZ continues from 08N129W to beyond 06N140W. Scattered to locally numerous moderate to strong convection is noted N of line from 04N78W to 08N97W. Scattered moderate to strong convection is noted from 04N to 13.5N between 100W and 119W. Scattered moderate isolated strong convection is noted within 60 nm S and 90 nm N of trough and ITCZ between 120W and 140W.


Fresh to strong S to SW winds are across the northern Gulf of California this afternoon, while recent scatterometer data showed moderate to fresh S to SW winds occurring across the remainder of the Gulf, with fresh SW gaps in the vicinity of Isla Espiritu Santo. Peak seas are 5 to 7 ft in the northern Gulf. Fresh NW winds prevail near Cabo San Lucas and curl around the southern end of the peninsula. Gentle to moderate NW to NNW winds prevail elsewhere off the coast of the Baja California peninsula, and also from near Cabo Corrientes southeastward to offshore of Mexico, and become fresh along the coast of Oaxaca. Light to gentle mainly NW to W winds are elsewhere over the open waters off Mexico. Seas of 6 to 9 ft in NW swell prevail west of the Baja California peninsula, and 6 to 7 ft seas in long-period southerly swell are across the offshore waters of central and southern Mexico.

For the forecast, fresh to strong S to SW winds will prevail across the northern Gulf of California through tonight and then gradually diminish Sat. Seas are expected to peak at 6 to 8 ft this afternoon and evening. Fresh NW to W winds are expected along the coast of Cabo San Lucas tonight through Sat morning, while fresh N to NW winds are expected off of Cabo Corrientes. Moderate to locally fresh W to NW winds will then prevail from near Cabo Corrientes to offshore Oaxaca through Mon afternoon. Moderate NW swell west of the Baja California peninsula, and moderate southerly swell off the central and southern Mexico coast will continue through midweek next week.


Please see the Special Features section for information on the development of a potential heavy rainfall event.

Convergent monsoonal winds are initiating scattered showers and thunderstorms near the coast of Panama, Colombia and Costa Rica this afternoon, and are likely to begin moving ashore this evening and tonight. Light to gentle winds near the monsoon trough along with 5 to 7 ft seas can be found over the offshore waters of Guatemala, El Salvador and Nicaragua. Gentle to moderate S to SW monsoonal winds and seas of 6 to 7 ft dominate the offshore waters of Costa Rica, Panama and Colombia. Moderate southerly winds and 6 to 8 ft seas are present near the Galapagos Islands and off the Ecuador shore.

For the forecast, periodic heavy showers and strong thunderstorms associated with the Central American Gyre will linger across the offshore waters of Costa Rica, Panama, Colombia through Sat, and Nicaragua, El Salvador, Guatemala through at least Sun. Moderate to fresh SW winds across the southwestern offshore waters of Nicaragua, Costa Rica, Panama and Colombia will gradually subside to gentle by tonight. East to southeast winds off the Papagayo region are going to pulse to fresh late Sun night through Mon morning. Moderate southerly swell should continue across all the offshore waters well into next week.


A ridge of high pressure extends southward into the area waters from high pressure centered over the NE Pacific, and extends across the waters north of the ITCZ and monsoon trough and west of 125W. The pressure gradient between the ridge and lower pressure associated with the ITCZ and monsoon trough is maintaining moderate NNE to NE winds and seas of 6 to 7 ft north of the ITCZ and monsoon trough and west of 130W, and fresh to locally strong NNW winds north of 25N between 122W and 130W, where seas are 8 to 13 ft in fresh northerly swell. Gentle to moderate southerly winds and 5 to 7 ft seas are noted south of the ITCZ and monsoon trough and west of 95W, except 7 to 8 ft south of 10N between the Galapagos Islands and 110W. Refer to the Monsoon Trough/ITCZ section for location of the active weather in this area.

Fresh to locally strong northerly winds well off Baja California Norte will subside to between moderate and fresh Sat morning, then increase again Mon morning. Seas in this area will also decrease to 8 to 9 ft by Sun morning. Southerly winds south of the ITCZ and monsoon trough should increase slightly to between moderate and fresh early next week. Seas between the Galapagos Islands and 110W will subside to 6 to 8 ft by early Sun then increase to 7 to 8 ft Sun through Mon as new SW swell arrives. Little change is expected elsewhere across the area.

$$ Stripling