981 AXPZ20 KNHC 192102 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2102 UTC Wed Sep 19 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 2030 UTC. ...SPECIAL FEATURES... Tropical Depression Nineteen-E centered near 27.0N 111.2W at 19/2100 UTC or 60 nm N of Loreto Mexico moving N at 8 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Associated numerous moderate and scattered strong convection is in the Gulf of California and adjacent areas within 180 nm in the E quadrant, with additional scattered moderate and isolated strong convection within 270 nm in the S quadrant and also from 28N to 29.5N. The depression only has 12 hours or less over water and is forecast to dissipate by 24 hours. Even so, heavy rainfall, with 5-10 inch areal average amounts and local amounts to 15 inches may lead to life-threatening flash flooding and landslides near the track of the depression. In addition, areas of heavy rain and a heightened risk of flash flooding in the SW United States is possible through Thu. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP4/WTPZ34 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N74W to 11N93W to 07N109W to 08.5N118W, then resumes from low pressure near 16N120W to 11N140W. Scattered moderate and isolated strong convection is from 03N to 10N to the E of 85W including the Gulf of Panama, from 08N to 12N between 88W and 91W, from 06N to 11N between 106W and 110W, from 13N to 16N between 120W and 126W, from 09N to 12N between 119W and 126W, and also from 12.5N to 15.5N between 128W and 134W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on Tropical Depression Nineteen-E located in the central Gulf of California. Elsewhere high pressure NW of the area supports moderate to fresh NW winds W of Baja California Norte, with gentle to moderate winds offshore to the S of there. Seas are 5 to 7 ft across the offshore waters W of the peninsula, except to 8 ft W of 118.5W. The pressure gradient will relax by Thu night allowing for winds and associated seas to diminish and subside for the start of the upcoming weekend. NW winds are forecast to increase back to moderate to fresh for the second half of the weekend into early next week as the gradient tightens just W of the Baja California Peninsula. A locally tight pressure gradient will support pulsing nocturnal northerly winds to fresh offshore of the Gulf of Tehuantepec the next several nights, except slightly weaker Fri night. Light to gentle variable winds will prevail elsewhere, except moderate to fresh near Cabo Corrientes mainly at night Thu night and Fri night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Offshore nocturnal winds will pulse to moderate to occasionally fresh near the Gulf of Papagayo the next several nights. Cross-equatorial SW swell with seas of 4 to 7 ft reaching the coast of Central America will gradually subside during the upcoming weekend. Otherwise, the monsoon trough will meander between 09N and 11N during the next several days, with mainly gentle winds N of the axis, and moderate S of the axis. REMAINDER OF THE AREA... Elongated surface troughing extends from near the southern tip of the Baja California Peninsula to weak 1008 mb low pressure near 16N120W where the monsoon trough continues SW-W from there. Ridging extends from NW to SE across the waters N of the trough and monsoon trough. Moderate to locally fresh trades are N of the convergence zone with moderate to locally fresh S of the troughing. The trade winds are supporting seas of 7 to 9 ft across the W central waters. These seas will subside to less than 8 ft by the end of the week as the ridge and troughing break down allowing for the pressure gradient to relax. $$ Lewitsky