000 AXPZ20 KNHC 181527 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1525 UTC Mon Mar 18 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A high pressure ridge across SE Mexico is supporting strong to minimal gale force gap winds funneling through the Chivela Pass this morning. An overnight scatterometer pass confirmed winds to minimal gale force north of 15N over the Gulf of Tehuantepec. Seas up to 14 ft this morning will gradually subside later today while NE swell continues propagating downstream beyond 10N. Northerly winds will continue to pulse to minimal gale force Tue night through Thu night with the strongest winds expected during the overnight and early morning hours. Please read the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from the coast of Costa Rica near 09N83W to 06N87W to 03N95W. The ITCZ continues from 03N93W to 01N100W to 02N110W to 04N125W to beyond 06N140W. Scattered moderate convection is noted within 60 nm of the trough between 85W and 95W, and within 120 nm north of the ITCZ between 105W and 110W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for more details about the Gale Warning in the Gulf of Tehuantepec. Gulf of California: Available overnight scatterometer data showed light to gentle winds over the Gulf as a weak pressure gradient prevails across the region. A weakening cold front will approach the northern Gulf late Tue night into Wed. This will result in moderate to fresh S to SW gap winds developing north of 29N that will continue into Wed night. Otherwise, light to moderate winds will prevail across the region through Fri night. Elsewhere, high pressure centered west of Baja California is supporting moderate N to NW winds over the northern waters that will persist through Tue night. NW swell associated with a dying cold front will spread across the area Tue night through Wed night with seas building to 11 ft off Baja California Norte. The NW swell will reach the Revillagigedo Islands by Thu, then gradually decay through late week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: A north-south pressure gradient across Central America is supporting strong to near gale force winds over the Gulf of Papagayo this morning with seas to 10 ft in SW swell and NE wind waves. Fresh to strong NE to E winds will continue pulsing across the Gulf through Fri night. The strongest winds are expected during the overnight and early morning hours with the assistance of nocturnal drainage flow. Gulf of Panama: Fresh to locally strong northerly winds across the Gulf of Panama early today will diminish to moderate to fresh speeds tonight into Tue, then further diminish by midweek. Between Ecuador and the Galapagos Islands, 5-7 ft seas in SW swell will persist through Tue night. Elsewhere, generally light to moderate winds and 3-5 ft seas will prevail for the next several days. REMAINDER OF THE AREA... A strong cold front extends from 30N134W to 26N136W to 22N140W this morning. Overnight scatterometer data showed a broad area of 25-30 kt winds ahead of the front. At 12Z, the highest seas to 16-17 ft were analyzed well behind the front near 30N140W. Strong winds will impact the waters north of 25N through tonight as the front moves eastward. Large NW swell behind the front will propagate across the region with 8 ft seas reaching to near 120W by Tue night. Elsewhere, high pressure centered near 26N123W is maintaining a broad ridge axis that extends southeast toward the Revillagigedo Islands. The pressure gradient between the ridge and the ITCZ supports moderate to fresh trade winds mainly S of 18N to the ITCZ. Earlier altimeter data indicated seas to 9 ft across this region with NW and SW swell combining with shorter period NE wind waves. High pressure will build across the far northwest waters Wed and move eastward through Fri night. The enhanced pressure gradient will result in strong trade winds S of 20N to the ITCZ with seas to 12 ft on Wed in mixed NW and NE swell. Another cold front will approach from the northwest toward the end of the week with more large long period NW swell. $$ Reinhart