000 AXPZ20 KNHC 052208 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Jun 5 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 1800 UTC surface analysis and satellite imagery through 2145 UTC. ...SPECIAL FEATURES... Low pressure located a few hundred miles south of Manzanillo Mexico is slowly becoming more organized. Latest satellite imagery shows that the overall cloud pattern is showing more of cyclonic signature. A 1007 mb low was analyzed near 14N105W at 18Z. The imagery shows numerous strong convection 12N to 15N between 105W and 108W. Scattered to locally numerous strong convection is from 12N to 15N between 103W and 105W. Scattered strong convection is seen from 12N to 15N between 100W and 103W. Very active weather is expected to persist across this region, and environmental conditions look favorable for continued development of the low pressure system, with a high chance of it becoming a tropical depression tonight or Wed. For the time being, a gale warning has been issued for the low beginning early on Wed when it is forecast to be near 14N106W with a pressure of 1005 mb. Winds of 30-35 kt are forecast within the 150 nm of its eastern semicircle along with seas of 10-17 ft. By Thu afternoon, strong gale force winds of 35-45 kt, with seas to near 19 ft are forecast within 60 nm of the low, and winds to 35 kt elsewhere within 90 nm of the low with seas of 11-17 ft. Please refer to the latest eastern North Pacific Tropical Weather Outlook under WMO/AWIPS headers ABPZ20 KNHC/MIATWOEP for the latest information on this system. ...TROPICAL WAVES... A tropical wave is over Central America with axis along 87.5W and north of 12.5N to the Gulf of Honduras and to just east of Belize, moving westward about 16 kt. It appears that the southern part of the wave is helping to enhance deep convection occurring to the south of the monsoon trough as described above. Scattered strong convection is increasing over some sections of northern Panama. The wave is forecast to move across the far eastern Pacific waters through the end of the week. Low pressure is expected to form along the wave. A tighter gradient behind the wave should is producing fresh winds across the Papagayo region. These winds should continue through the rest of this week, with some pulsing of them to moderate intensity expected at times. Active convection will continue to accompany this wave. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Panama to developing low pressure of 1007 mb near 14N105W to 09N116W to 08N126W, where it transitions to the ITCZ to beyond 07N140W. In addition to the convection associated with the low pressure described under the Special Features section, scattered strong convection is within 60 nm of the trough between 108W-111W. Scattered moderate to strong convection is along and within ' 240 nm south of the trough between 82W-90W. Scattered moderate isolated strong convection is within 180 nm south of the trough between 115W-118W, and also within 60 nm south of the trough between 111W-115W and between 118W and 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad ridge extends east-southeastward from a large 1031 mb high pressure system centered north-northwest of Hawaii near 34N166W to a 1028 mb high near 32N141W and 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 4-5 ft are forecast to gradually build to 5-7 ft Thu and 6-8 ft Thu night and Fri in the waters offshore northern Baja California due to a new set of NW swell forecast to propagate through those waters. Inside the Gulf of California, generally southerly wind flow is expected to continue through Thu. Afternoon and 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 the cyclonic circulation associated with low pressure expected to form along a tropical wave described above begins to impact the waters downstream from the Gulf of Tehuantepec. 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. Moderate to locally fresh nocturnal drainage flow across and downstream of the Gulf of Papagayo will be prolonged through Fri as a tighter gradient behind a tropical wave, presently along 87.5W, keeps these winds mostly in the fresh range. The monsoon trough meanders 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. REMAINDER OF THE AREA... The surface ridge extending across the northern waters will gradually shift W 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 Special Features low pressure system tracks in a general northwesterly motion. The seas of up to 8 ft that were over the far western portion of the area last night and this morning south of 10N and west of 134W have subsided to less than 8 ft. Northerly swell producing seas to around 8 ft propagating through the NE waters N of 29N between 122W and 127W will gradually subside by early Wed afternoon. Long period SW swell crossing the Equator from the southern Hemisphere will cause seas near the Equator between 92W and 130W to build to 8 ft on Wed night. This area of 8 ft seas will continue to propagate northward and merge with the area of 8 ft seas associated with the area of developing low pressure to the southwest of Mexico by Fri evening. The area of 8 ft seas will expand to include almost all of the basin to the south of 23N between 100W and 130W during this time frame. $$ Aguirre