000 AXPZ20 KNHC 170922 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sun Dec 17 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 06.5N92W TO 10N120W TO 08.5N134W TO beyond 09.5N140W. Scattered moderate isolated strong convection is noted within 120 nm of the ITCZ between 102W and 117W. Scattered weak to moderate convection is noted from 07N to 17N W of 131W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: A deep layered low pressure system has moved SE across the Pacific waters of Baja California Norte tonight and into the northern Gulf of California. This system supports a 1004 mb surface low near 32N114W 1004 mb with a cold front extending SSW across Baja California Norte to 28N114W then continues SW and then W TO 25N124W TO 27N130W. The upper low has intensified in recent hours and is producing scattered moderate convection aloft to the N of 27N and within 75 nm E of the cold front. The front is expected to continue moving SSE and gradually dissipate over the S central Gulf on Mon. S to SW winds over the northern and central Gulf ahead of the front have strengthened. The main issue tonight will be the likelihood of strong W to NW winds over the northern Gulf as the surface low pressure shifts eastward into the Sonora Desert. While the fetch across the northern Gulf will be too limited to develop large seas, mariners should be aware of the possibility of strong gusty winds funneling through low lying areas of Baja California Norte through early Sun. Winds will diminish through early next week after the front dissipates. Across the Pacific offshore waters, NW winds have strengthened behind the front to 20-25 kt, and seas have built to around 15 ft along 120W. Seas are expected to build to as high as 16 ft in NW swell by Sunday morning, then start to subside by afternoon. Seas of 8 to 10 ft will cover most of the waters beyond 60 nm of the Baja coast through early next week. Elsewhere gentle to moderate winds and 3 to 5 ft seas will persist along the coast of Mexico outside of the Gulf of Tehuantepec through mid week. Gulf of Tehuantepec: A small plume of strong northerly winds continues across the Gulf of Tehuantepec tonight but will diminish quickly this morning through the afternoon. Starting tonight, nocturnal drainage winds will pulse to strong through midweek. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Strong offshore winds are occurring across the Gulf of Papagayo tonight and extend downwind to near 89W. These strong gap winds are expected to continue across the Papagayo region for the the next few days. Fresh N winds are funneling across the Gulf of Panama currently and will do so again tonight. REMAINDER OF THE AREA... Fresh to strong winds prevail over the waters N of 24N, with seas 9 to 15 ft in northerly swell. Seas associated with this swell will peak near 16 ft early this morning before starting to subside. Moderate to fresh tradewinds prevail elsewhere over the forecast waters north of the ITCZ to 20N and west of 125W, and have diminished W of 135W tonight as a trough to the W of the area has moved farther W and away from the area. High pressure across the NE Pacific will dominate the regional waters for the next few days with little change in tradewinds. However the latest northerly swell event across the region will fade through Tue and allow seas to gradually subside to 6 to 9 ft areawide. $$ Stripling