NHC Tropical Weather Discussion (East Pacific) National Hurricane Center - Tropical Weather Discussion (East Pacific)

  • NHC East Pacific Tropical Weather Discussion

    503 AXPZ20 KNHC 132221 CCA TWDEP Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 2205 UTC Wed Nov 13 2019 Corrected Remainder of the Area section 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 2200 UTC. ...SPECIAL FEATURE... A well-defined low pressure system, analyzed as 1008 mb low on the latest surface analyzed, is located roughly about several hundred miles south of the southern tip of the Baja California peninsula is producing a large area of disorganized showers and thunderstorms. This activity is observed to be of scattered moderate to isolated type intensity. Gradual development of the low is expected over the next several days, and a tropical depression is likely to form by late this week while the system moves slowly northward. However, upper-level winds are forecast to become unfavorable for any further development of this disturbance by late this weekend. The latest Tropical Weather Outlook gives this system a medium chance of tropical cyclone formation through 48 hours. Refer to the latest NHC Tropical Weather Outlook under AWIPS/WMO Headers MIATWOEP/ABPZ20 KNHC for more information. A Gale Warning remains in effect for the Gulf of Tehuantepec. A strong ridge across the eastern slopes of the Sierra Madre mountains in Mexico and the western Gulf of Mexico supports a gap wind event across the Tehunatepec region consisting of north to northeast winds of 30-35 kt, with wave heights in the 10-14 ft range. As the pressure gradient over southeastern Mexico continues to slacken through early on Thu, this will allow for these winds to diminish to strong speeds. Wave heights at that time will subside to 9-12 ft. Both global and regional models are consisting forecasting another strong gale force wind event across the Gulf of Tehuantepec region from Fri through Sat night. See the latest High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC or the website https://www.nhc.noaa.gov/text/ MIAHSFEP2.shtml for further details. ...TROPICAL WAVES... A tropical wave with axis along 82W and north of 05N is moving westward at about 10 kt. Scattered moderate convection is observed across the western sections of Panama and over some sections of southern Costa Rica. Isolated showers and thunderstorms are within 180 nm either side the axis from 05N to 09N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1009 mb low over northwestern Colombia westward to across Panama and to 09N84W to 08N93W to low pressure of 1008 mb near 11N111W to 14N121W to low pressure near 12N125W 1009 mb and to 08N131W, where latest scatterometer data indicates the ITCZ begins and continues to beyond the area at 07N140W. Scattered moderate to isolated strong convection is within 60 nm north of the trough between 91W and 94W. Scattered moderate convection is seen within 120 nm south of the trough between 101W and 107W and also within 120 nm south of the trough between 107W and 110W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special FeatureS section above for details about an ongoing gale force wind event in the Gulf of Tehuantepec. A ridge dominates the offshore waters west of Baja California, supporting gentle to moderate northerly winds and wave heights of 4 to 6 ft. Little change is expected through Thu. Winds and seas will diminish across the waters west of Cabo Corrientes later today as high pressure in northern Mexico shifts eastward. Light and variable winds will prevail in the Gulf of California through Sat. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate southwest monsoonal flow will continue across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador the next several days. Wave heights will remain in the 4-7 ft range. Large north to northeast swell generated from the present ongoing Gulf of Tehuantepec gale wind event is currently reaching the western and southern sections of the Guatemala offshore waters, with wave heights in the range of 8-12 ft. These wave heights will gradually subside through Thu morning as the winds diminish in the Tehuantepec area and the large area of swell downstream from the Gulf decays. REMAINDER OF THE AREA...Corrected A dissipating cold front extends from near 32N135W to 25N140W. Winds of 20 kt or less and seas less than 8 ft are associated with the front. Large-long period northwest well associated with an intense low pressure system in the central north Pacific will reach the far northwestern waters on Thu, with wave heights peaking near 12 ft in the far northwest corner of the area by Thu evening. Low pressure of 1009 mb is observed near 13N125W. Latest satellite imagery shows what appears to be an exposed low-level circulation, with isolated showers and thunderstorms within 120 nm of the low in the southeast and west quadrants. Ascat data from this afternoon highlighted 20-25 kt northeast winds in the northwest quadrant of the low. Environmental conditions are expected to be unfavorable for any significant development of this disturbance while it moves generally in a westward motion. $$ Aguirre