000 AXPZ20 KNHC 202202 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Dec 20 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 2115 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... TROUGH FROM LOW PRES 1009 MB NEAR 06N78W TO 05N90W TO 07N97W TO 08N104W. ITCZ CONTINUES TO 09N120W TO 08N135W TO 10N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 120 NM SW OF LOW PRES 1009 MB NEAR 06N78W. Precipitation: SCATTERED MODERATE ISOLATED STRONG WITHIN 210 NM N OF ITCZ BETWEEN 108W AND 118W...AND WITHIN 150 NM S OF ITCZ BETWEEN 109W AND 117W. SCATTERED MODERATE ISOLATED STRONG FROM 13N TO 19N BETWEEN 107W AND 110W...AND FROM 18N TO 20N BETWEEN 115W AND 116W. ...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 28N on Thursday, and from 24N to 27N on 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 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 Monday night/early on 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 with an axis from 24N127W to 11N111W supports numerous moderate and isolated strong convection from 12N to 20N between 107W and 115W. 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 18N and west of 135W Friday through Saturday night. Winds will diminish from south to north as the low lifts northeast during this time, with forecast models suggesting the low center will clip our waters near 30N140W Saturday night. Seas of 8 to 15 ft 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. However, lingering swell of 8 to 12 ft will remain over the NW waters N of 20N and west of 133W through early next week. $$ mt