000 AXPZ20 KNHC 130246 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0235 UTC Wed Sep 13 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 0230 UTC. ...SPECIAL FEATURES... Tropical Depression 15-E centered at 15.4N 118.5W at 0300 UTC moving W or 265 degrees at 12 knots. The minimum central pressure is estimated 1004 mb. The maximum sustained winds are 30 kt with gusts to 40 kt mainly over the NW semicircle. Scattered moderate to strong convection is observed within 225 nm over the NW and SW quadrants. Easterly upper-level wind shear is expected to limit the potential for much intensification of the depression during the next few days. The depression is forecast to move W and strengthen to a minimal tropical storm within 24 hours and then gradually weaken to a remnant low within 3 days near 15.5N125.1W. For additional information refer to NHC forecast advisories under WMO/AWIPS headers WTPZ25 KNHC/MIATCMEP5. An elongated area of low pressure located a couple of hundred miles south of the southern coast of Mexico is producing numerous showers and thunderstorms. Environmental conditions are expected to be conducive for development of this system, and a tropical depression will likely form during the next day or so before it moves over southwestern Mexico. Regardless of development, locally heavy rains are expected to spread inland over southwestern Mexico later this week. These rains could cause life-threatening flash floods and mudslides. This system has a high chance of development during the next 48 hours. A broad area of low pressure located several hundred miles south of the southern tip of the Baja California peninsula is producing disorganized showers and thunderstorms. Environmental conditions are expected to be conducive for development of this system, and a tropical depression is likely to form by the end of the week while it moves slowly northward. This system has a medium chance of development during the next 48 hours. ...TROPICAL WAVES AND TROPICAL LOWS... A 1008 mb low is embedded in the monsoon trough at 11N135W with scattered moderate convection from 10N to 12N between 133W and 138W. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 12N87W to Tropical Depression 15-E to low pres near 11N135W 1008 mb to beyond 11N140W. Aside from the convection related to the T.D. and the low along 135W, scattered moderate convection is noted from 10N to 16N between 96W and 114W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW to SE oriented trough will meander E to W across the Baja California Peninsula and the Gulf of California with a surface low developing intermittently along the trough axis over the far northern Gulf waters, and perhaps also over the central Gulf of California. A W to E orientated ridge will meander from 27.5N128W to 22N115W through the middle of the week, with a moderate W to NW breeze forecast across the EPAC waters S and W of the Baja California Peninsula through Thu night, with 5 to 6 ft seas. Gulf of California...Light, mostly NW winds expected through the next 24 hours. Gulf of Tehuantepec: Moderate nocturnal drainage flow is forecast through the period. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to locally fresh southwesterly monsoonal flow expected this week. Combined seas are currently 6 to 8 ft primarily due to cross-equatorial swell that is forecast to subside today with seas forecast less than 8 ft tonight. REMAINDER OF THE AREA... See the Special Features section above about T.D. 15-E and the other areas of active weather with potential to become tropical systems. A surface ridge extends from 31N140W to 24N119W with light to locally moderate anticyclonic flow expected elsewhere N of the monsoon trough and W of 110W through the week. $$ ERA