000 AXPZ20 KNHC 120256 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Jun 12 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 0000 UTC surface analysis and satellite imagery through 0215 UTC. ...SPECIAL FEATURES... Tropical Depression Three-E near 15.2N 94.9W at 12/0300 UTC or about 78 nm south-southeast of Salina Cruz, Mexico moving N NW at 4 kt or 335 degrees. Estimated minimum central pressure is 1007 mb, along with maximum sustained winds of 30 kt gusts to 40 kt. The depression has a well-defined surface circulation as was noted in an Ascat pass from Sunday afternoon. Last visible satellite imagery showed a rather symmetrical shape to the overall cloud pattern. Latest satellite imagery reveals scattered moderate to isolated strong convection within 60 nm southwest and northwest of the center. Scattered moderate convection is present elsewhere within 120 nm of the center in the southwest quadrant, and also within 30 nm either side of a line from 14N93W to 14N92W. The depression is forecast to move to near 15.6N 95.2W early on Monday, and gradually intensify into a tropical storm near 16.0N 95.7W early Monday evening with maximum winds 35 kt gusts to 45 kt. The tropical storm is then forecast to weaken back to a depression early on Tuesday near 16.3N 96.3W, and continue inland to near 16.4N 96.9W Tuesday evening. The main issue with this system will be the expected heavy rainfall across Guatemala, and portions of southeastern Mexico. These rains may result in life- threatening flash floods and mudslides. Please see the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MITCPEP3/WTPZ33 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCPEP3/WTPZ23 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The Monsoon Trough axis extends from 09N79W to 12N86W to 14N93W. It resumes at 13N97W to 10N105W to 07N112W to 07N120W, where scatterometer winds indicate the ITCZ axis begins and continues to 09N131W where it briefly ends. It resumes at 08N134W to beyond the area at 06N140W. Scattered moderate to strong convection is noted from 05N to 09N between 78W and 81W. Scattered moderate isolated strong convection is noted within 60 nm south of the axis between 135W and 140W. Scattered moderate is within 60 nm of the axis between 108W and 110W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See above for details on newly formed Tropical Depression Three-E. Elsewhere, a tight gradient over northern Baja California and the northern portion of the Gulf of California is inducing strong south to southwest winds over the Gulf north of 29.5N, while moderate to fresh northwest winds are occurring off the western coast of the northern Baja California peninsula. Light to gentle winds prevail elsewhere. Seas are in the 4 to 6 ft range over the coastal waters and northern Gulf of California, while seas in the central and southern Gulf of California are in the 1 to 3 ft range. Winds will diminish over the Gulf of California by early on Monday. Northwest winds are forecast to increase to fresh to strong offshore the northern Baja California peninsula late tonight, then diminish to mainly fresh winds on Monday afternoon before increasing again to fresh to strong Monday evening, and diminishing to fresh winds by early Tuesday afternoon. However, residual northwest swell will maintain combined seas of 8 to 9 ft offshore the northern portion of the Baja California peninsula on Tuesday. Looking ahead toward the middle portion of the upcoming week, there is a very good potential for a significant heavy rain event over portions of Central America and southern Mexico. Model guidance is suggesting that a large cyclonic gyre is forecast to develop during the middle to end of the week, and move slowly over the northern portion of Central America and southern Mexico. Abundant tropical moisture will be advected over these areas with the potential for heavy rainfall which may produce life threatening flash floods and mudslides. This is something to keep an eye on over the next few days as the scenario unfolds. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see above for the potential of heavy rainfall over the northern portion of Central America later this week. Elsewhere, gentle to moderate westerly winds and 4 to 6 ft seas are expected north of 07N...and gentle to moderate southwest to west winds with 5 to 7 ft seas forecast south of 07N through Wednesday night. REMAINDER OF THE AREA... A strong 1031 mb high pressure center located to the northwest of the discussion area near 35N150W extends a ridge southeastward to 32N140W to 26N130W and to near 20N115W. A well- defined surface trough is along 133W from 08N to 14N, moving west at about 13 kt. An Ascat pass from Sunday afternoon nicely captured the northeast to southeast wind shift across the trough. Satellite imagery shows scattered moderate isolated strong convection within 180 nm east of the trough, and from 05N to 08N between 130W and 133.5W. The pressure gradient between the high pressure ridge and trough will keep fresh northeast winds with seas of 5 to 7 ft from about 12N to 16N west of 130W through Monday afternoon. Eleswhere, moderate to locally fresh winds continue to the north of the ITCZ with seas in the 4 to 6 ft range. High pressure will strengthen over the next couple of days increasing the coverage of fresh winds, and building seas to the 6 to 8 ft range. $$ Aguirre