000 AXPZ20 KNHC 152205 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sat Jun 15 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 2145 UTC. ...TROPICAL WAVES... A tropical wave with axis along 100W from 05N to 16N is moving westward near 15 kt. Scattered moderate isolated strong convection, aided by the tail-end of a mid to upper-level trough, has flared up during the afternoon within 120 nm to the east of the wave from 13N to 16N. Scattered showers and isolated thunderstorms are seen elsewhere north of 13N between 98W and 101W. A tropical wave with axis along 118W from 04N to 15N is moving westward at 15-20 kt. Scattered moderate convection is occurring within 120 nm east of the wave from 12N to 15N. A tropical wave with axis along 139W from 03N to 14N is moving westward near 17 kt. This wave is entering an environment consisting of strong upper-level west winds. Satellite imagery only shows isolated showers and thunderstorms from 05N to 13N west of 136W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from just offshore Colombia in the SW Caribbean Sea to across the central part of Panama and southwestward from there to 09N78W to 10N91W to 11N101W and to 11N112W, where latest scatterometer data indicates that it transitions to the monsoon trough and briefly ending at 11N117W. It resumes to the west of the tropical wave analyzed along 118W at 11N119W and continues from there to 10N128W and to 08N138W. Scattered moderate to isolated strong convection is noted north of the ITCZ within 30 nm either side of a line from 13N112W to 13N116W, and also within 90 nm north of the ITCZ between 124W and 128W. Scattered moderate convection exists within 180 nm south of the trough between 82W and 88W, and within 150 nm north of the ITCZ between 128W and 133W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient between a high pressure ridge west of Baja California and a low pressure trough along the Baja California peninsula is maintaining moderate northwest to north winds across most of the adjacent offshore waters where seas remain in the 4-5 ft range. Winds and seas off Baja California will change little through early on Mon as the ridge remains over offshore waters. However, winds will pulse to fresh speeds near the coast during the evening hours through Sun night mainly in the region between Punta Eugenia and Cabo San Lazaro. Low pressure is expected to cover a rather expansive area over the southwestern United States and along California by late Mon afternoon in response to a sharpening mid/upper-level trough that will pass over those regions. This will result in a weakening of the ridge allowing for offshore wind speeds to briefly diminish through middle part of the upcoming week. Mainly moderate southeast to south winds were captured by an Ascat pass over the southern half of the Gulf of California. These winds will diminish slightly early on Sun. By late Sun night, gentle to moderate southeast to south winds will over the entire Gulf and through Mon. Winds will increase to fresh speeds over the far northern part of the Gulf Mon night before diminishing to moderate speeds early on Tue. Long-period southwest swell is reaching the Mexican offshore waters, however, with most of the energy spent already, the seas will remain in the 5-6 ft ft range through the middle of the upcoming week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong nocturnal offshore winds will continue pulsing across the Gulf of Papagayo region through the middle part of the upcoming week, with seas peaking around 7-8 ft downstream of the Gulf. Otherwise, fairly tranquil conditions will persist off Central America under a weak pressure pattern. Gentle to moderate south to southwest flow with scattered showers and thunderstorms will prevail south of the monsoon trough through the weekend and early next week. Long-period southwest swell will propagate through the southern waters through tonight building the waveheights to 8 ft between Ecuador and the Galapagos Islands through the rest of this weekend. Another set of south to southwest swell will move into the southern waters Tue night, once again resulting in 8 ft seas off the coast of Ecuador. REMAINDER OF THE AREA... A high pressure ridge prevails across the northern waters. Moderate to fresh northeast winds are between the ridge and the ITCZ west of 120W. Seas in this region are generally 5-7 ft based on the latest altimeter data. Moderate to locally fresh trades are expected to persist mainly south of 20N through the remainder of this weekend and early next week as a couple of tropical waves moves south of the ridge. Long period southwest swell will continue to propagate through high seas areas east of 120W through Sun night. Seas will remain 8 ft or greater south of the Equator through the middle of the upcoming week, as a reinforcing set of southwest swell is expected to reach the far southwestern waters by Mon night. Expect 8-10 ft seas south of the Equator and west of 100W by Tue. Elsewhere, northwest to north swell will impact the far northern waters west of about 125W beginning on Mon night and continuing through Wed night as strong high pressure builds southward to the north of the area. Waveheights associated with the swell will likely build to 8-10 ft north of 28N. $$ Aguirre