000 AXPZ20 KNHC 080915 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue May 08 2018 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 0915 UTC. ...SPECIAL FEATURE... A persistent broad area of low pressure is analyzed as a 1010 mb surface low at 09N121W. Environmental conditions are favorable for slow development over the next few days as the low moves moves northwestward. A blend of global guidance results in a solution of a surface low near 12N122W tonight accompanied by strong to near gale force winds. The forecast is for minimal gale force conditions to develop within 75 nm over the north semicircle of the low near 12N123W on Wed. Gale conditions should continue through early Fri when environmental conditions will become less favorable. This system has the potential to become a tropical cyclone. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends west-southwest from the Pacific coast of Costa Rica at 09N83W to 08N90W to 10N100W through an embedded surface low at 09N121W to 05N124W where scatterometer winds indicate an ITCZ develops and continues west to beyond 03N140W. Scattered moderate isolated strong convection is observed within 120 nm either side of a line from 06N93W to 11N102W to 10N111W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A northwest to southeast ridge will meander from near 21N116W to 18N107W through Wed, then retract north-westward as a weak tropical low develops well south of the Mexican offshore waters near 10N108W. A tightening pressure gradient will increase the northwest flow to a fresh breeze, accompanied by 7 to 10 ft seas, across the waters from 29N to 32N west of Baja Norte today with locally strong winds forecast on Wed through early Fri. The associated northerly swell will propagate as far south as 25N on Thu before beginning to subside from the south. Gulf of California: Light, mostly southerly flow forecast through the middle of the week, except moderate nocturnal drainage flow expected near gap areas. Guidance is suggesting fresh to strong southwesterly flow developing along 30.5N on Fri and continuing into early Sat. Gulf of Tehuantepec gale warning: Strong to near gale force northerly flow will continue through sunrise this morning. This gap event should end by late Wed morning with winds diminished to 20 kt or less. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh nocturnal winds are expected through tonight, followed by moderate nocturnal flow on Wed night. Light to gentle nocturnal flow is then expected on Thu night with moderate flow on Fri night. Gulf of Panama: Light to gentle northerly nocturnal flow is forecast through this week. REMAINDER OF THE AREA... Refer to special features section for a warning associated with a tropical low pressure developing near 12N122W. A weakening cold front extending southwest from 32N134W to 25N140W will continue east and weaken to a frontal trough from 32N128W to 24N140W early Wed, and then dissipate by late Wed. Long period northwest swell in the form of 10 to 16 ft seas is expected west of the front today. These large seas will quickly subside to 6 to 9 ft west of the frontal trough early Wed, and further subside to less than 8 ft across the tropics during the middle of the week. Seas of 8 to 11 ft are forecast across the subtropics, generally north of 24N east of 124W late in the week. $$ Nelson