873 AXPZ20 KNHC 161551 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Jun 16 2020 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 1520 UTC. ...TROPICAL WAVES... A tropical wave is along 87W-88W, moving west at 10 kt. Scattered moderate isolated strong convection is active N of line from 03N77W to 08N90W, and extends across the W Caribbean Sea and adjacent coastal portions of Nicaragua and Honduras. A tropical wave is along 100W, moving west near 10 kt. Scattered to numerous moderate to strong convection is ongoing from 07N to 13N between 96W and 109W. A tropical wave is along 116W, moving west around 10 to 15 kt. Scattered moderate isolated strong convection is noted from 07N to 16N between 110W and 120W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N75W to 11N99W to 10N111W to 13N117W to 10N130W. The ITCZ continues from 10N131W to 07N140W. Scattered moderate isolated strong convection is active N of line from 03N77W to 08N90W. Scattered to numerous moderate to strong convection is ongoing from 07N to 13N between 96W and 109W. Scattered moderate isolated strong convection is noted from 07N to 16N between 110W and 120W. Scattered moderate to strong convection is noted from 07N to 14.5N between 120W and 130W. Scattered moderate isolated strong convection is within 180 nm N of the ITCZ W of 131W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The mid to upper level pattern remains fairly amplified. A long- wave, upper trough reaches from the northeast Gulf of Mexico to the far southwest Gulf of Mexico and across the Gulf of Tehuantepec region. This upper trough is interacting with the tropical wave along 87W to deepen a resident trough over the Yucatan peninsula and southwest Gulf of Mexico. This is maintaining a tight pressure gradient between the trough and higher terrain over southern Mexico, allowing strong northerly gap winds to funnel across the Gulf of Tehuantepec. An overnight scatterometer satellite pass indicated 25 kt winds in the Gulf of Tehuantepec. These winds are pulsing, with the strongest pulses occurring during the overnight hours with the help of local drainage effects. A recent altimeter satellite pass showed seas to 7 ft just outside of the main plume of winds, so highest wave heights are estimated to be 8 to 9 ft. These seas are mixing with longer period SW swell persisting in the region. This pattern will continue into Wed. By late week, the upper trough will have dampened out and moved east, allowing the gap wind flow and related seas to diminish. Farther north, another mid to upper trough reaches from the central Rockies through the northern Gulf of California. This pattern is tightening the pressure gradient between lower pressure over northwest Mexico and higher pressure west of the area. This has resulted in fresh to strong westerly gap winds overnight over the northern Gulf of California, that have shifted more SW this morning. NW swell producing seas of 6 to 7 ft persists in the outer offshore waters of Baja California Norte. This will briefly increase to 7-8 ft this afternoon and evening, then subside tonight, before another pulse of NW swell to 8 ft will enter the waters northwest of Guadalupe Island by mid week. Looking ahead, moderate to fresh NW winds are possible off Baja California Sur by late week as a ridge builds into the area. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate SW monsoon flow prevails south of the monsoon trough, with gentle to moderate winds to the north of the monsoon trough. Seas are in the 5-7 ft range, mainly south of Panama. This will subside through mid week, but another round of SW swell is expected later in the week. REMAINDER OF THE AREA... A ridge extends from 1030 mb high pressure centered near 37N144W E-SE to off Cabo San Lucas. The pressure gradient between this area of high pressure and lower pressure in the vicinity of the ITCZ is supporting fresh trade winds from 10N to 20N west of 125W. Seas are in the 7 to 9 ft range over this area in a mix of swell. Moderate to fresh winds, and seas of 5 to 7 ft, prevail elsewhere north of the monsoon trough/ITCZ. Moderate southerly flow prevails south of the monsoon trough/ITCZ. Long-period southerly swell still dominates the waters south of 10N and east of 110W, with 6 to 8 ft seas prevailing. Another round of southerly swell will enter the area late in the week. $$ Stripling