000 AXPZ20 KNHC 121620 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Sep 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Tropical Depression 15-E centered at 15.6N 116.2W at 1500 UTC moving W or 260 degrees at 13 knots. The minimum central pressure is estimated 1004 mb. The maximum sustained winds are 20 to 30 kt with gusts to 40 kt mainly over the NW semicircle. Scattered moderate to strong convection is observed within 150 nm over the NW quadrant and within 270 nm across the SW quadrant of the depression. 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 15.6N122.7W. For additional information refer to NHC forecast advisories under WMO/AWIPS headers WTPZ25 KNHC/MIATCMEP5. Active convection persists along the monsoon trough today and is being aided by a broad zone of strong SW monsoon winds. A surface low is forecast to develop along the trough in the vicinity of 102W tonight and may develop quickly into a tropical cyclone within the next two days. Another surface low is forecast to develop further W along the trough in the vicinity of 112W where global models suggest another tropical cyclone could develop during the next several days. Global models also indicate that very active convection will continue along and south of the trough during the next several days. Currently strong S to SW winds are occurring from 06N-12N between 100W- 115W, where seas are running 8 to 12 ft in cross equatorial southerly swell. Models are general agreement on the development of these two systems by exact location vary. However, the broad zone of strong monsoon winds and seas of 8-11 ft and higher will continue across the general area for the next few days as the trough and associated weather drift slowly northward. ...TROPICAL WAVES AND TROPICAL LOWS... A 1010 mb low is embedded in the monsoon trough at 11.5N134W with isolated moderate to strong convection is observed within 90 nm of the low. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N75W TO 09N79W TO 14N91.5W TO TROPICAL DEPRESSION 15-E AT 15.6N116.2W TO low pres near 11.5N134W 1010 MB TO beyond 10.5N140W. Scattered moderate to strong convection is noted E of 81W and within 270 nm S of the monsoon trough between 92W and 132W. ...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 23N116W to 21N110W 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 Wed. Gulf of Tehuantepec: Strong to near gale force northerly flow continued through sunrise this morning, with seas 10 to 12 ft downstream of the gulf waters. Winds will diminish steadily today, with only moderate nocturnal drainage flow forecast tonight. 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 special features paragraph. A ridge extends from 32N138W to 23N116W with light to locally moderate anticyclonic flow expected elsewhere N of the monsoon trough and W of 115W through the middle of the week. $$ Stripling