Pacific Discussion

  • NHC East Pacific Tropical Weather Discussion
    by (nhcwebmaster) on May 26, 2019 at 9:24 PM

    203 AXPZ20 KNHC 262123 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1946 UTC Sun May 26 2019 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 meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... ...Heavy Rainfall Potential Over Central America... A large low level cyclonic circulation that is typical for this time of the year, called a Central American Gyre, is forecast to persist across the far eastern tropical Pacific and Central America for the next several days. This will continue bringing abundant moisture and areas of heavy rainfall across portions of Central America. Computer model forecasts have begun to indicate the chance for increasing moisture and instability associated with this feature Tue through Wed and could lead to a very significant rainfall event. Life-threatening flash flooding and mudslides will be possible in areas of mountainous terrain. Please refer to your local meteorological service for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends across northern Costa Rica to a low pressure located near 10N88W 1010 mb to 08N100W to 06N120W TO 06.5N130W. The ITCZ extends from 06.5N130W to beyond 07N140W. Scattered moderate to strong convection is noted from 05.5N TO 14N between 80W AND 106W. Scattered moderate isolated strong convection is noted from 05N TO 12N between 84W AND 106W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Fresh to strong winds are noted per scatterometer data across the northern part of the Gulf. Over the central and southern parts of the Gulf, mainly light and variable winds prevail, with seas 2 ft or less. Winds will begin to shift more NW tonight through Mon as a series of weak cold frontal boundaries approach and sweep eastward across the northern Gulf tonight through Tuesday. Winds across central and southern portions will increase to 10-15 kt during this time with seas building 2-3 ft. A weak ridge dominates the offshore forecast waters W of Baja California producing mainly gentle to moderate NW winds off the coast of the Baja California peninsula, and light to gentle NW to W winds over the remainder of the open waters off the coast of Mexico. Seas are generally in the 5-7 ft range across the entire area in a mix of NW and cross equatorial SW swell. High pressure well NW of the region will build over the next few days. This will tighten the pressure gradient across the offshore waters to support fresh to locally strong NW to N winds across the waters off Baja California tonight through Tue night, with seas building into the 6 to 8 ft range. Gulf of Tehuantepec: Fresh to strong northerly winds will pulse across the Tehuantepec region late tonight into early Monday morning, with seas of 7 to 8 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features section for more information about the Central American Gyre, which will continue to bring locally heavy rains to parts of Central America and the adjacent offshore waters through at least mid week. Gentle to moderate SW to W winds prevail S of the monsoon trough, with seas in the 4-7 ft range. Moderate to locally fresh winds, and seas in the 5-6 ft range prevail N of the monsoon trough. Low pres embedded within the broad gyre will meander offshore the coast of Nicaragua the next couple of days. The monsoon trough will lift northward through the early part of the week, with southerly monsoon flow strengthening, potentially to 20-25 kt by Tue. Seas will build to 8-12 ft by mid week in this enhanced monsoon flow. REMAINDER OF THE AREA... High pressure of 1025 mb centered NW of the area near 34N139W extends a ridge SE to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ is supporting moderate to fresh NE winds across much of the area N of the ITCZ and W of 120W. Moderate to fresh winds will continue to prevail over this area the next several days. SW cross equatorial swell will dominate the forecast waters S of 10N and W of 95W for the next few days, with new swell arriving late Tue. Seas 8 ft or greater will cover much of the forecast waters S of 12N between 85W and 112W by Tue. $$ GR […]