000 AXPZ20 KNHC 210402 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Dec 21 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... TROUGH FROM 07N78W TO LOW PRES 1006 MB NEAR 05N79W TO 05N92W TO 07N101W. ITCZ CONTINUES TO 10N120W TO 09N127W BEYOND 09N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 360 NM N OF ITCZ BETWEEN 107W AND 122W...AND WITHIN 180 NM S OF ITCZ BETWEEN 112W AND 124W. Isolated moderate within 180 nm on either side of 22N112W 17N123W 14N132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Northerly winds will increase abruptly to fresh-to-strong behind the next cold front expected to move through most of the basin early Thursday through Friday. These winds will cover the area from 27N on Thursday, and from 24N to 28N on Friday. A small area of fresh-to-strong wind will be present on the western side of the southern tip of Baja California during parts of the afternoon and evening of Friday. The wind speeds should slow down to moderate-to-fresh on Saturday. The sea heights will reach their maximum, near 8 feet, on Friday, from north to south. Gulf of Tehuantepec: Northerly winds will pulse from fresh to strong starting during the overnight hours of tonight and ending Thursday in the afternoon. Northerly strong-to-near gale force winds are possible early on Sunday morning, with sea heights ranging from 8 feet to 9 feet. N-to-NE gale-force winds start late on Sunday/early on Monday morning, and continue until Tuesday morning. It is possible that the sea heights may reach 16 feet during the early morning hours of Tuesday morning. A strong cold front is forecast to move across the Gulf of Mexico, and the winds will funnel through the Chivela pass into the Gulf of Tehuantepec. Elsewhere across the offshore waters of Mexico, mainly gentle to moderate winds are expected the next several days, with the exception of briefly fresh winds from Manzanillo to Cabo San Lucas as high pressure builds NW of the region Friday and Saturday. Seas of 4 to 6 ft will persist during the next several days, except near 7 ft where the fresh winds are occurring. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong winds will prevail from Thursday into Friday morning, with the sea heights reaching near 7 feet on Thursday. The wind speeds will slow down to moderate-to-fresh on Friday. Gentle-to-moderate winds, and sea heights ranging from 5 to 7 feet, will persist elsewhere over these waters through the upcoming weekend. REMAINDER OF THE AREA... Moderate to fresh east to northeast winds prevail over the waters from the ITCZ to 30N, driven by high pressure centered north of the region. These winds support 6 to 8 ft seas in a NW swell. To the south of the ITCZ, moderate SE winds prevail with seas of 5 to 7 ft. An upper trough, from 23N128W to 13N117W to 01N106W, supports isolated moderate rainshowers from 14N to 22N between 106W and 117W. High pressure will build SE toward California on Friday while low pressure develops west of our waters near roughly 22N147W. The pressure gradient between these two features will support fresh to strong SE winds north of 16N and west of 126W Friday through Saturday night. The wind speeds will diminish from south to north as the low pressure center lifts northeastward during this time. Forecast models suggest that the low pressure center will reach our waters near 30N140W Saturday morning/early afternoon. Sea heights ranging from 8 feet to 15 feet are expected during this time period over these affected waters. Later in the forecast period, a weaker pressure pattern will result in mainly moderate winds over the area. Lingering swell of 8 to 12 ft will remain in the NW waters N of 20N and west of 133W through early next week. $$ mt