000 AXPZ20 KNHC 190937 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Aug 19 2019 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... A 1009 mb low pressure area is located near 13N92.5W, or about 90 nm SW of the Guatemala/Mexico border. The low is moving WNW at around 5 kt which is expected to continue as it parallels the Mexican coast. The center has moved closer to the deep convection on the NW side, with new convection also developing on the SE side in the past few hours. Numerous moderate and scattered strong convection is noted within 240 nm in the NW quadrant, with scattered moderate and isolated strong convection elsewhere within 600 nm in the NW quadrant, and within 90 nm in the SE quadrant. The threat for heavy rainfall and potential flash flooding will be over Guatemala, Chiapas, and Oaxaca over the next couple of days. Fresh to strong winds and seas of 5 to 8 ft will gradually increase and build through the week. This low has a medium chance of tropical formation through the next couple of days. A 1009 mb low pressure area is located near 13N119W, or about 900 nm SW of the southern tip of Baja California. The low is moving W at 5 to 10 kt. Numerous moderate and scattered strong convection is noted within 150 nm in the SW quadrant, with scattered moderate and isolated strong convection elsewhere within 240 nm in the W quadrant. Fresh to occasionally strong winds and seas of around 8 ft are forecast to accompany the low. This low has a medium chance of tropical formation through the next couple of days. Refer to the latest NHC Tropical Weather Outlook under AWIPS/WMO headers MIATWOEP/ABPZ20 KNHC for more information on both of these lows. ...TROPICAL WAVES... A tropical wave axis is along 110W, moving W at around 5 kt. Scattered moderate convection is noted from 07N to 10N between 105W and 108W, and also from 10N to 11N between 110W and 113W. A tropical wave axis is along 130W/131W, moving W at around 5 kt. A weak area of low pressure, around 1009 mb, is located just to the E of the wave near 14N128W. Scattered moderate and isolated strong convection is noted within 180 nm in the NW quadrant of the low, and also from 08N to 12N between 122W and 130W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N79W to low pressure near 13N92.5W to 11N110W to low pressure near 13N119W to low pressure near 14N128W to low pressure near 12N136W to 11N140W. Scattered moderate and isolated strong convection is noted within 150 nm SW of the coast of Central America E of 90W, and also within 150 nm S of the axis between 95W and 100W. Scattered moderate convection is noted from 08N to 10N between 130W and 140W, and also from 11N to 13N between 138W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more details about the low pressure area S of the Guatemala/Mexico border which is approaching the Gulf of Tehuantepec region. A weak high pressure ridge extends SE across the waters N of 20N bringing gentle to moderate NW winds. This ridge will slowly shift SE into the middle of the week, causing the pressure gradient to increase later today through the middle part of the week. This will support moderate to fresh NW winds offshore of Baja California Norte, becoming fresh to strong Tue night. A low pressure trough will develop along the Baja California peninsula Wed night through the end of the week, supporting the development of fresh SE to S winds in the northern Gulf of California. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features section for more details about the low pressure area S of the Guatemala/Mexico border. Offshore winds will pulse to fresh in the Gulf of Papagayo through this evening, then again Wed night and Thu night. Long period SW swell will impact the offshore waters W of Ecuador by the middle of the week, building seas to 5 to 8 ft, then subsiding by the end of the week. Otherwise, mainly moderate W to SW winds will prevail S of 10N, along with seas of 4 to 6 feet. REMAINDER OF THE AREA... Please see the Special Features section for more details about the low pressure area near 13N119W. Weak low pressure of 1011 mb is near 11.5N136W, with limited convection in its vicinity. The low is forecast to move W of 140W by Tue. A weak ridge extends SE from 1021 mb high pressure near 39N137W. Recent scatterometer data showed mainly gentle trades N of the monsoon trough, while altimeter data sampled 4 to 7 ft seas. The ridging will remain in place through the week, with the pressure gradient tightening, which will support increasing trades. The pressure gradient will also increase offshore of central and southern California by the middle of the week, sending fresh northerly swell of 7 to 9 ft into the waters N of 25N and E of 125W. $$ Lewitsky