000 AXPZ20 KNHC 132127 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1808 UTC Sat Oct 13 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 2100 UTC. ...SPECIAL FEATURES... A small, well-defined low pressure system located more than 100 miles southwest of Acapulco, Mexico, continues to produce a concentrated area of showers and thunderstorms near and just west of the center. Upper-level winds are expected to be marginally conducive for development of a tropical depression during the next few days while the disturbance moves moves slowly westward to west-northwestward parallel to the southwestern coast of Mexico. However, only a slight deviation to the right or north of the expected track would bring the small low and its heavy rains closer to or even inland along the southwestern coast of Mexico, which would inhibit further development. Interests in this area should monitor the progress of this system. See latest Tropical Weather Outlook under AWIPS/WMO Headers MIATWOEP/ABPZ20 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from a 1007 mb low pressure system located near 16N101W to 11N120W to 12N133W to beyond 10N140W. Scattered moderate convection is N of 10N to the coast of Mexico and Central America between 87W-105W, and within about 210 nm S of monsoon trough between 114W-124W. Scattered moderate to isolated strong convection is noted from 06N-13N between 130W- 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge dominates the offshore waters W of Baja California Peninsula producing mainly light to gentle winds. Seas of 6 to 7 ft are still noted per altimeter data just W of Baja California Sur, and near the entrance of the Gulf of California. These seas, associated with long period SW swell, are expected to subside to 5-6 ft by tonight. Gentle to moderate NW-N winds, and seas generally in the 4 to 6 ft range are expected beginning on Mon as high pressure builds W of Baja California. Gulf of California: The most recent scatterometer pass indicates fresh to strong winds across the northern Gulf likely associated with a 1011 mb low pressure currently moving across southern California. These winds are forecast to diminish to 20 kt or less by tonight. On Mon, strong to near gale force NW winds are expected N of 27N in response to very strong high pressure building over the Great Basin of the United States. Winds could gust to gale force for the waters N of 29N when this event peaks by late Mon. Seas to 9 ft are possible in the northern Gulf Monday, then seas will gradually subside below 8 ft by Tue evening as winds die down. Gulf of Tehuantepec: Next gap wind event is forecast to start early on Wed with seas rapidly building to 10 ft later on Wed. This event will be associated with a ridge building across the eastern slopes of Sierra Madre Mountains in Mexico and the western Gulf of Mexico. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh SW monsoonal flow will continue across the region through Tue, with showers and thunderstorms expected to continue along the Pacific coast of Central America. Long period cross-equatorial southwest swell will maintain 5 to 8 ft seas across the forecast area during this time frame. By Tue night into Wed, marine guidance suggests an increase in winds and seas across the offshore waters from Costa Rica to Guatemala. This could be associated with a broad area of low pressure moving from the SW Caribbean into Central America next week. REMAINDER OF THE AREA... A cold front has reached the north-central waters, and extends from 31N122W to 29N126W to 30N132W. Gentle to moderate NW winds are in the wake of the front, forecast to gradually dissipate across the NE waters through Sun. Another cold front will approach to the far NW corner by late Mon. Fresh to strong southerly winds and seas to 9 ft are forecasted ahead of the front. The front will reach a position from 30N139W to 28N140W by early Tue morning. Scatterometer data confirmed the presence of moderate to fresh monsoonal flow S of 10N W of 100W, with an area of seas to 8 ft in long period SW swell, affecting the waters from 05N-10N between 100W-120W. These seas will merge with cross equatorial SW swell on Mon. Gentle to moderate trades and seas of 5 to 7 ft can be expected for the waters N of the monsoon trough, S of 20N and W of 120W. $$ GR