000 AXPZ20 KNHC 162131 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Aug 16 2017 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. ..TROPICAL WAVES... A tropical wave is N of 10N along 81W. Scattered moderate convection is observed within 90 nm on either side of the wave axis from 10N to 15N. This convective activity is now affecting parts of eastern Honduras and Nicaragua. This wave has been progressing W at about 20 kts across the western Caribbean, but is expected to slow its forward speed over the the next few days. A tropical wave is N of 10N along 102W and has moved W at 15 kt over the past 48 hours. Scattered moderate and isolated strong convection is noted from 10N to 16N between 100W and 102W. An earlier ASCAT pass showed the wind shift associated with this wave as well as moderate to fresh winds on either side of the wave axis. The wave coincides with a well defined 700 mb trough, and a high amplitud northward bulge of moisture is noted on the TPW product. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 08N90W to 12N101W to a 1010 mb low pressure near 11N107W to 13N123W to 11N134W to 13N140W. Scattered moderate convection is N of 06N between 80W and 84W. Scattered moderate isolated strong convection is from 07N to 10N between 89W and 94W, from 10N to 12N between 112W and 124W, and within 120 nm S of the monsoon trough W of 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge will dominate the forecast waters west of Baja California producing mainly gentle to moderate northerly winds and seas in the 4-6 ft range the remainder of the work week. A surface trough will meander across the Baja California Peninsula and Gulf of California through Sat night, with a surface low developing intermittently over the northern Gulf of California. Gulf of California...gentle to locally moderate southerly flow will persist across the Gulf of California through the upcoming weekend, with the exception of moderate to locally fresh winds that will surround the low pressure center over the waters N of 30N. Gulf of Tehuantepec: fresh to strong northerly winds are expected, with the assistance of the drainage flow, during the overnight and early morning hours Thursday through Sunday. Seas are forecast to build to 6-8 ft with these winds. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: moderate to fresh offshore winds are expected during the overnight and early morning hours through Friday morning with gentle to moderate winds thereafter. Gentle NE to E winds are expected N of the monsoon trough, while moderate southerly winds are expected S of the monsoon trough axis through the upcoming weekend with 3 to 6 ft seas throughout. REMAINDER OF THE AREA... A surface low of 1008 mb is analyzed within the monsoon trough at 11N107W. A cluster of moderate to isolated strong convection is noted within 120 nm W semicircle of the low center. Scattered moderate isolated strong convection is elsewhere from 07N to 14N between 106W and 111W. An earlier scatterometer pass provided observations of fresh to strong SE to S winds on the east side of the low center, likely associated with an area of strong convection previously noted in association with this low. Marine guidance indicates fresh to strong winds in the NE quadrant of the low center first, then in the N semicircle thereafter. The low is forecast to reach near 12N111W on Thu and near 11N116W on Fri. Another surface low pressure is near 17N118W. Convection is limited in association with this low. Satellite imagery shows only scattered moderate convection within 75 nm S semicircle of low center. the most recent ASCAT pass provided observations on fresh to strong winds within 120 nm NE semicircle of low with seas to 8 ft. These marine conditions will persist during the next 24 hours when the low is forecast to reach a position near 16N121W. The remnants of former tropical cyclone Jova continue to spin near 18.5N132W with a central pressure of 1009 mb. A swirl of low clouds is still noted related to this low. The pressure gradient between the low and a ridge to the north is supporting moderate to fresh winds and seas of 7 to 8 ft ft within about 180 nm NW quadrant of low. This feature is forecast to move toward the SW and weaken to an open trough by Fri. The subtropical ridge dominates the north waters producing mainly gentle to moderate winds. An area of seas to 8 ft in southerly swell covers the waters SE of a line from 11N105W to 06N115W to another line from 11N102W to 06N108W. These seas will propagate westward, and subside to less than 8 ft on Friday. $$ GR