000 AXPZ20 KNHC 201559 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Thu Jun 20 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 12O0 UTC surface analysis and satellite imagery through 1545 UTC. ...TROPICAL WAVES... A western Caribbean Sea tropical wave has its axis along 80W and extending southward to near 07N. Increasing deep convection is occurring near where the wave axis crosses the monsoon trough as described below. A tropical wave with axis along 92W from 04N to 15N moving westward at 10-15 kt. Scattered to numerous moderate to strong convection is seen from 12N to 14N between 91W and 94W. A tropical wave with axis along 104W from 04N to 14N is moving westward near 15 kt. Only scattered showers and isolated thunderstorms are noted west of this wave to 107W and from 08N to 13N. A tropical wave with axis along 124W from 04N to 15N is moving westward at an estimated speed of 15-20 kt. Scattered moderate convection is within 180 nm either side of the wave axis from 11N to 15N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1008 mb low over northern Colombia southwestward to 08N78W to 10N88W to 09N98W to 08N105W to 12N118W to 09N126W and to 08N130W, where overnight scatterometer data indicated that it transitions to the ITCZ to 08N130W and to beyond 08N140W. Numerous to strong convection is within 180 nm south of the trough between 78W and 81W. Scattered moderate to strong convection is within 60 nm either side of the trough between 82W and 89W. Scattered moderate convection is within 60 nm of the trough between 96W and 101W, and also within 60 nm south of the trough and ITCZ between 127W and 134W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Overnight scatterometer data continued to show gentle to moderate northwest wind across offshore waters as weak high pressure dominates E of 130W. Overnight altimeter satellite data showed seas at 4-5 ft. Low pressure over the western U.S. will deepen some today, and a surface trough will continue to extend from this low over Baja California. This will cause winds to increase over the northern Gulf of California, producing strong to near gale force south to west gap winds beginning early this evening. These winds will diminish to mainly fresh speeds by early Sat afternoon before increasing again to strong speeds late on Fri night and into early Sat. Farther south, the northern part of a weak tropical wave will brush the extreme southern part of the Mexican offshore waters through early Fri. Scattered to numerous showers and thunderstorms, with possibly strong gusty winds, will impact these waters as the wave passes across there. Otherwise, little impact in winds and seas is expected. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate breezes will prevail over most of the waters into the weekend. The earlier winds of 20-25 kt that pulse through the Papagayo region late last night and into this morning will diminish to fresh winds late this afternoon. These winds will pulse to around 20 kt again tonight and into early next week. These gap winds are due to a tight pressure gradient between high pressure north of the Caribbean sea and the lower pressure associated with the monsoon trough. Overnight altimeter satellite passes showed seas of 4-7 ft prevailing as southerly swell will continue to be dominant into the weekend. REMAINDER OF THE AREA... A 1031 mb high remains quasi-stationary well north of the area near 42N139W, with a ridge extending southward to the tropical region west of 125W. South of this ridge, generally northeast to east trades in the range of 15-20 kt are occurring across the tradewind belt south of 18N, and these trades should persist through the weekend. North of 25N, seas of 8-10 ft are occurring, due to northerly swell generated by gale force winds occurring off the west coast of the United States. This set of swell will shrink some in size as it shifts eastward through the weekend. Farther south, long-period cross-equatorial swell is causing seas of 8-9 feet south of about 07N. This swell will decay some toward the end of the week, before new swell arrives this weekend, again increasing seas south of 08N to possibly 8-10 feet. $$ Aguirre