000 AXPZ20 KNHC 072150 CCA TWDEP Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 1605 UTC Thu Jun 7 2018 Corrected Special Features section 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...SPECIAL FEATURES...Corrected Tropical Storm Aletta is centered near 14.9N 109.3W at 1500 UTC, or about 380 nm SW of Manzanillo, Mexico, moving WNW or 290 deg at 5 kt. Maximum sustained winds have increased to 60 kt with gusts to 65 kt. Minimum central pressure is estimated at 991 mb. Latest satellite imagery shows scattered strong convection within 90 nm NE and 60 nm NW quadrants of the center. Scattered moderate isolated strong convection is located elsewhere within 180 nm in the NE quadrant, 210 nm in the SE quadrant and 120 nm in the western semicircle. Similar convection is within 30 nm of a line from 13N103.5W to 15N103.5W, and within 60 nm of 11N111W. Aletta is gradually becoming better defined in its overall cloud pattern as by its increase of banding features and what appears to be small central dense overcast over the center. Per the 1500 UTC NHC advisory, Aletta is forecast to move generally west-northwestward to northwest over the next few days. It is forecast to strengthen to a minimal hurricane by this evening with maximum sustained winds of 65 kt gusts to 80 kt as it moves over very warm sea surface temperatures and remains under favorable upper- level conditions. Please refer to the latest NHC Forecast Advisory under WMO/AWIPS headers WTPZ22/MIATCMEP2, and the NE Pacific High Seas Forecast under WMO/AWIPS headers FZPN03/MIAHSFEP2 for the latest information on this system. A tropical wave is along 94W north of 09N extending inland across southeastern Mexico in the Gulf of Tehuantepec region, moving westward at 10 to 15 kt. The southern part of the wave is helping to enhance deep convection occurring to the south of the monsoon trough as described above. Scattered moderate isolated strong convection is noted within 60 nm of 12N90W. Scattered moderate convection is present from 10N to 15N between 92W and 96W. The wave is forecast to move slowly westward during the next 48 hours, at which time low pressure is expected to form along it near 10N98W. Model guidance suggests that upper-level conditions are forecast to become favorable for this system to develop during the upcoming weekend. This system has a medium potential for development during the next couple of days. Fresh easterly flow behind this system is expected to increase to strong Fri through Sat, with some chance of these winds increasing further as the low pressure deepens. This tightening of the gradient will bring fresh northeast to east winds across the Gulf of Papagayo region through the upcoming weekend. Please refer to the latest NHC Tropical Weather Outlook under header ABPZ20/MIATWOEP for the latest potential for development on this system. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia to southern Costa Rica/northern Panama to 10N91W to 11N100W, where it has fractured from Tropical Storm Aletta. It then resumes at 11N116W to 07N126W, where the ITCZ then continues to beyond 06N140W. Scattered strong convection is within 60 nm south and 30 nm north of the trough between 84W and 86W. Scattered moderate isolated strong convection is noted within 120 nm south of the trough between 94W and 102W. Scattered moderate convection is within 30 nm of the ITCZ between 128W and 132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad ridge extends from a 1023 mb high pressure system centered near 31N136W southeastward to near the Islas Revillagigedo. The typical low pressure trough will remain over the Baja Peninsula and Gulf of California through Fri. This pressure pattern will generally support moderate to fresh northwest winds west of the Baja Peninsula through Fri. Seas of 4-7 ft overnight are forecast to build to 6 to 8 ft later today due to a new pulse of NW swell, with the swell forecast to expand in areal coverage through the next few days. Inside the Gulf of California, generally light to gentle southerly wind flow is expected to continue through the weekend. Afternoon to evening sea breezes are forecast to dominate the Gulf for the next few days and will freshen the winds to around 20 kt along the coasts each day. Variable light to gentle winds are expected across the Gulf of Tehuantepec through Thu night, then a brief episode of fresh to strong northerly winds will flow across the Gulf of Tehuantepec Fri as a cyclonic circulation associated with a tropical wave as described above begins to impact the waters downstream from the Gulf of Tehuantepec through most of Fri. Latest computer models suggest that this low could become better organized over the weekend as it moves westward and offshore of Acapulco. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fuego Volcano in Guatemala may resume venting some ash in the coming days, but remains relatively quite since the major eruption this past Sunday. Moderate to locally fresh nocturnal drainage flow across and downstream of the Gulf of Papagayo will be prolonged through Fri as a tighter pressure gradient develops behind a tropical wave, presently along 94W, keeps these winds mostly in the fresh range. The monsoon trough will meander across the forecast waters near 10N. Gentle to moderate E winds are generally forecast elsewhere north of the monsoon trough through Thu night. Gentle to moderate southwest winds are forecast south of the monsoon trough through Sat. SW cross equatorial swell will move into the regional waters over the upcoming weekend and raise seas to 6 to 8 ft by Sun. REMAINDER OF THE AREA... The surface ridge extending across the northern waters will gradually shift westward during the next few days. Fresh trades will continue across the tropics to the south of the ridge, generally from 08N to 18N west of 125W through Fri. Model guidance indicates that these winds increase in coverage late Fri as the Aletta tracks in a general west-northwesterly motion. NW to N swell producing seas to around 8 ft will propagate through the northeast waters N of 28N between 117W-122W beginning tonight, and reach south to near 24N between 117W to 124W early on Sat, raising seas 7 to 9 ft. Long period cross equatorial SW swell will build seas near the Equator between the Galapagos Islands and 100W to 8 ft Fri tonight. The long period SW swell will continue to propagate northward and merge with swell associated with Aletta by Sat, with expected seas in the 8 to 10 ft range. The area of 8 ft seas will impressively expand to include almost all of the basin to the south of 24N between 100W and 135W over the upcoming weekend. $$ Aguirre