000 AXNT20 KNHC 120559 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 159 AM EDT Sat Oct 12 2019 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... Subtropical Storm Melissa is centered near 37.7N 68.8W at 11/0300 UTC or 250 nm S of Nantucket Massachusetts moving SSE at 3 kt. Estimated minimum central pressure is 997 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Scattered moderate convection prevails across the northern semicircle to 180 nm from the center. Melissa is forecast to weaken during the next couple of days and is expected to become a remnant low by Sat night or early Sunday. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT4/WTNT34 KNHC for more details. ...Gulf of Mexico Gale Warning... A cold front over the NW Gulf extends from 29N91W to 23N97W near Tampico, Mexico. The front will reach from the mouth of the Mississippi River to Veracruz by Sat afternoon. Behind the front, strong to gale force northerly winds are expected along the Mexican coastal waters beginning early Sat morning. Winds will diminish across the area Sun morning. Refer to the High Seas Forecast product under AWIPS/WMO headers HSFAT2/FZNT02 KNHC for more details. ...Heavy rainfall event for Central America... A broad area of low pressure is expected to form over the SW Caribbean Sea this weekend. This system is forecast to move westward toward Central America early next week, and some development is possible if the low remains over water while moving near the coasts of Honduras, Guatemala, and Belize. As the low tracks westward toward Central America by early next week it will likely interact with a Central American gyre. Through the weekend, heavy rainfall is likely across Colombia, Panama, Costa Rica and eastern portions of Nicaragua and Honduras. By early next week, the heavy rain will continue in those locations and spread northwestward to the rest of Central America as well as southern Mexico. These rains could cause life-threatening flash flooding and mudslides. ...TROPICAL WAVES... An eastern Atlantic tropical wave has an axis from 19N32W to 02N32W, moving W at 10 kt. This wave is well depicted in satellite imagery and model guidance. Scattered showers are noted along the northern portion of the wave mainly north of 10N and near the monsoon trough from 01N-04N between 28W-33W. A central Atlantic tropical wave has an axis along 51W from 09N- 21N, moving W at 10 kt. Scattered moderate convection is over the northern portion of the wave from 18N-24N between 49W-54W. This convection is enhanced by an upper level low centered to the northwest of the wave well depicted by the ASCAT. ...MONSOON TROUGH/ITCZ... The monsoon trough extends SW from the coast of Africa near 17N16W to 07N35W. The ITCZ extends from 07N35W to 07N49W. Besides the convection mentioned in the tropical wave section, isolated moderate convection seen along the monsoon trough from 05N-08N between 34W-37W, and scattered showers along the ITCZ from 05N- 10N between 41W- 49W. GULF OF MEXICO... Refer to the section above for details on the Gale Warning currently in effect. A cold front has entered the northwest Gulf of Mexico, extending from 29N91W to 23N97W near Tampico, Mexico, then continues as a cold front in Mexico until it transitions to a stationary front through Northern Mexico. Scattered moderate isolated strong convection is noted along the frontal boundary from 23N-27N between 91W-96W. Gale winds are present behind this front in the NW Gulf with a Gale Warning in effect. Isolated strong tstorms are seen in the Bay of Campeche from 19N-21N and west of 95W. Surface ridging prevails across the remainder of the basin. The cold front over the NW Gulf will stall during the evening hours Sat. The front will then lift back towards the NW gulf through Sun where it will dissipate. Strong to minimal gale force northerly winds are behind the front and will extend towards the waters near Veracruz tonight through Sat evening. Winds will diminish across the entire area Sun as high pressure north of the area slides eastward. CARIBBEAN SEA... Refer to the sections above for details on the tropical wave over the west Caribbean and the heavy rainfall event currently occurring over Central America and the SW Caribbean. TPW imagery depicts abundant moisture over the southern Caribbean and northern South America. The Pacific monsoon trough extends from Colombia westward across the SW Caribbean Sea into northern Costa Rica and southern Nicaragua. Scattered moderate isolated strong convection covers the SW Caribbean mainly south of 16N and west of 71W. A broad area of low pressure just east of Nicaragua continue to support scattered showers and isolated tstms over the SW Caribbean and portions of the NW basin. A new area of low pressure is forecast to develop over the SW Caribbean on Sun. This system is forecast to move westward toward Central America early next week, and some development is possible if the low remains over water while moving near the coasts of Honduras, Guatemala, and Belize. Fresh to strong winds are expected over portions of the SW and NW Caribbean late in the weekend into early next week associated with this system. ATLANTIC OCEAN... Refer to the section above for details on the Sub-Tropical Storm Melissa and tropical waves moving across the basin. A stationary front extends south from a 1010 mb low pressure centered near 33N62W SW in the W-central Atlantic from 30N63W to 24N70W to 23N76W near the central Bahamas. Scattered moderate convection is noted along the front mainly 80 nm ahead of the front from 25N-28N between 63W-66W. Two 1010 mb surface lows are NE of the Caribbean near 21N63W and 23N56W. A surface trough connects these lows and is producing scattered moderate to isolated strong convection from 20N-24N between 54W-63W. Surface ridging prevails across the remainder of the basin. A weakening cold front will push slowly SE and stall W of 60W on Sun before dissipating on Mon. High pressure behind the front will induce moderate to locally fresh northerly winds east of the Bahamas. Subtropical Storm Melissa well north of the area will continue to generate large N swell over a large portion of the western Atlantic through Sun. $$ MMTorres