000 AXPZ20 KNHC 261004 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Apr 26 2019 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 0945 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Scatterometer data from last night showed gentle northwest to north over the Gulf of Tehuantepec region along with seas of 3-4 ft. These conditions will begin to change in a short while as the gradient over southeastern Mexico begins to tighten. Strong north winds will begin across the Gulf of Tehuantepec this morning and continue through this evening, before a brief occurrence of minimal gale force northerly winds affects the Gulf of Tehuantepec region tonight due to a tight localized gradient that will become established just inland the Isthmus of Tehuantepec as high pressure over southeastern Mexico interacts with relatively lower pressure south of the Gulf. Expect for this short-lived gale event to last until early Sat morning. Waveheights are forecast to reach the range of 8-11 ft with this event before quickly subsiding to 8 ft by early on Sat afternoon and to less than 8 ft by late Sat afternoon. Seas of 8 ft will reach downstream from the Gulf to near 12N96W before subsiding Sat afternoon. Please refer to the East Pacific High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more specific marine details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from a 1009 mb low over northwestern Colombia to the coast at 04N77W, and continues to 03N81W and to 06N89W, where scatterometer data from last night indicated that it transitions to the ITCZ and continues to 08N100W to 07N114W to 06N121W to 07N131W and to beyond 06N140W. Scattered moderate to isolated strong convection is within 180 nm north of the ITCZ between 108W-112W and also within 180 nm north of the ITCZ between 119W-127W. Scattered moderate convection is within 60 nm south of the trough between 77W-80W, within 60 nm north of the iTCZ between 115W-117W and within 60 nm south of the ITCZ between 117W-119W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Relatively weak high pressure is present across these waters, with the associated gradient maintaining gentle to moderate northwest to north winds. Seas are in the 4-6 ft range. With the exception of winds briefly increasing to fresh speeds along and just offshore the central part of the Baja California Peninsula on Sat, expect for these conditions to change little through Sun night. A northwest swell will slightly increase the seas over in the extreme northwest section of the offshore waters on Mon night and Tue. Gulf of California: Fresh southwest gap winds will develop over the northern Gulf of California Sun night and to fresh to strong winds Mon and Mon night ahead of an approaching weakening cold front. These winds become mainly fresh south to southwest winds on Tue. Seas will be 3 ft or less in the Gulf, with the exception of seas building to 3-5 ft in the far northern part on Mon and subside to 3 ft or less on Tue. Gulf of Tehuantepec: See above for details regarding a short- lived and late season gale event forecast to begin tonight. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate east winds across the Gulf of Papagayo will strengthen to fresh speeds early Sat, then diminish to moderate winds Sat afternoon. This cycle will repeat itself Sun and Mon. These winds will increase to fresh to strong speeds Mon night into early Tue, while expanding west-southwest. Gulf of Panama: Moderate north to northeast winds will diminish slightly to gentle winds on Sat, then increase to moderate winds mainly at night through early next week. Seas of about 3-5 ft in this area will be mainly induced from a south to southwest swell. Wave heights between Ecuador and the Galapagos Islands are currently 3-6 ft in S to SW swell based on latest altimeter data in this region. Seas will build to 5-7 ft within the outer waters today as a new set of south to southwest swell moves into the area. These conditions will persist near the Galapagos Islands through Mon night. REMAINDER OF THE AREA... Moderate northeast to east trades are present over the waters roughly from 08N to 17N and west of about 117W as inferred from overnight scatterometer data. Latest altimeter data noted over this area suggests that waveheights are in the 6-8 ft range. Locally higher winds and seas are possible in and near scattered moderate to isolated strong that is occurring along and near the ITCZ as described above. Rather weak high pressure over the northern waters will maintain moderate trades through early next week. over the next several days with seas in the 6-8 ft range. A weak 1013 mb low near 29N136W has a trough extending from it to 23N139W and another one extending northwest to north of the area at 32N141W. The low will remain nearly stationary through tonight, then move east along 29N while pulling a developing cold front over the northern waters on Sat and Sat night. The front is expected to weaken to a trough Sun. Associated winds are expected to be 20 kt or less with seas less than 8 ft. Southwest swell will propagate into the far southern waters this morning and spread northward across much of the forecast area east of 120W through the weekend. Seas to 8 ft will generally be confined to the waters south of the Equator and west of 120W. $$ Aguirre