000 AXPZ20 KNHC 161555 RRA TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC THU JUN 16 2016 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... A large 1008 mb low is centered near 16N 106W. There is scattered moderate and isolated strong convection located within 180 nm of the center. The convection has not been persistent enough near the center to initiate Dvorak classifications. An ASCAT scatterometer pass at 0440Z indicated peak winds of strong breeze within 180 nm in the eastern semicircle. Some of these winds may be enhanced by funneling along the coast of southwestern mexico. There have not been any waveheight observations in the vicinity of the low, but based upon the 25 kt peak winds, it is likely that 8-9 ft seas are also present. Additionally, an 0840Z TOPEX altimeter pass showed that there are 8-9 ft seas present north of 05N between 95W and 105W primarily due to SW swell. The low is given a moderate chance...60%...of becoming a tropical cyclone as it moves toward the west-northwestward at 5 to 10 mph. After a couple of days, the low will be moving over waters too cool to be conducive for development. The forecast does not anticipate that the system will cause tropical storm force winds nor waveheights of at least 12 ft, even if it does become a tropical cyclone. ...TROPICAL WAVES... A tropical wave axis is near 87W south of 18N moving westward at 10-15 kt. The wave extends from the northwestern part of the Caribbean Sea, across Honduras, and over the Pacific Ocean to 08N. No significant deep convective precipitation accompanies the wave at this moment. The wave can be tracked with the total precipitable water imagery, the western Caribbean rawindsondes, and the SUNY-Albany tropical wave diagnostics. No significant development of this system is expected during the next few days. A second tropical wave axis is near 78W moving westward at about 15 kt. The wave extends from the southwestern Caribbean Sea, across Panama, and into the extreme eastern Pacific. No significant convection is present in association with this system. The wave is fairly subtle and only trackable with the SUNY-Albany tropical wave diagnostics. No significant development of this system is expected during the next few days. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the 1008 mb low pressure center at 16N106W - which is in the Special Features section - to 10N117W to 08N129W. The ITCZ continues from 08N129W to 09N134W to 07N140W. Scattered moderate and isolated strong convection exists within 120 nm of the monsoon trough between 113W and 123W. Scattered moderate and isolated strong convection is present within 60 nm of the ITCZ between 130W and 135W. A 1012 mb low pressure center is near 09N96W. Scattered moderate and isolated strong convection is present from 05N to 10N between 95W and 102W. No significant develop of this system is anticipated. ...DISCUSSION... From 15N northward and from 120W eastward: Seas of up to 8 ft are present just west of Baja California due to the combination of southerly swell and NW wind waves. These should diminish below 8 ft by Friday afternoon. Some enhanced NW winds to strong breeze conditions may occur on Sunday and Monday, likely boosting seas back up to 8-9 ft. No significant winds or seas are anticipated for the Gulf of California through Tuesday. From 15N southward and from 120W eastward: Except as noted for the low in the Special Features section. conditions are quiet. No significant gap wind events or other prospects for tropical cyclogenesis appear likely through Tuesday. On Sunday, a significant long-period SW swell event should begin reaching the equator and product 8 to 10 ft seas. These should spread up to about 10N by Tuesday. Elsewhere to the west of 120W: A weak 1015 mb low and associated cold front is located just west of California this morning. The front should reach our northwestern border at 30N140W, but not produce significant winds or waves in our area. A surface ridge of high pressure extends along 28N. The pressure gradient on the equatorward side of the ridge is rather weak and the resulting tradewinds are only moderate to fresh breeze. A small area near 13N west of 136W has seas to 8 ft in mixed NE wind waves and NE swell as observed by a TOPEX altimeter pass at 0330Z. These should diminish later today. On Sunday, a significant long-period SW swell event should begin reaching the equator and produce 8 to 10 ft seas. This will likely persist past Tuesday. $$ Landsea