000 AXNT20 KNHC 041802 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 PM EDT THU AUG 04 2016 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... Tropical Storm Earl is well inland over northern Guatemala near 17.3N 90.2W moving W at 10 kt. Estimated minimum central pressure has risen to 994 mb. Maximum sustained wind speed has decreased to 40 kt with gusts to 50 kt. Latest satellite imagery shows scattered moderate to isolated strong convection in bands over the western Gulf of Honduras. Scattered moderate convection is over much of Guatemala, and in narrow bands just north of northeast Honduras. Earl is forecast to weaken further to a tropical depression by this evening as tracks further inland. Earl is expected to produce total rain accumulations of 8 to 12 inches over portions of Belize, Honduras, Guatemala, and Mexican states of Campeche, Chiapas, Quintana Roo, Tabasco and Veracruz through Friday morning. Isolated maximum amounts of 18 inches are possible in Belize, northern Guatemala and the central part of the Mexican state of Chiapas. These rains could result in life-threatening flash floods and mudslides. Please see latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC and the full forecast/advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details. ...TROPICAL WAVES... Tropical wave axis in the central Tropical Atlantic extends from 20N45W to 14N46W to 07N45W, and is estimated to be moving west at 20 kt over the past 24 hours. The wave coincides with a 700 mb trough as depicted in the global models. It remains embedded within a low-amplitude surge of moisture with Saharan dry air and dust evident just northwest through north of the wave, as seen on the SSMI Total Precipitable Water Imagery. Scattered moderate convection is confined near the southern extent of the wave axis from 08N-11N between 45W-50W. Tropical wave axis in the central Tropical Atlantic extends from 21N57W to 14N58W to 09N58W...and is estimated to be moving west around 20 to 25 kt over the past 24 hours. The wave coincides with a 700 mb trough as depicted in the global models and is embedded within a deep surge of moisture as seen on the SSMI Total Precipitable Water Imagery. Latest satellite imagery shows quite an impressive flare up of scattered moderate to strong convection from 17N to 21N between the wave axis and the northern Leeward Islands. Upper level diffluence present over the northern portion of the wave is helping to sustain the aforementioned convective activity. This wave is forecast to move into the eastern Caribbean Sea tonight, then move through the central Caribbean Friday and the western Caribbean Saturday before moving west of the sea on Sun. Gusty winds can be expected with the wave as it quickly tracks across the Caribbean basin. ...ITCZ/MONSOON TROUGH... The Monsoon Trough axis extends across Africa into the eastern Tropical Atlantic near 11N16W to 10N29W to 08N37W. The ITCZ begins briefly at 08N37W and ends west of the southern portion of a tropical wave axis near 08N45W. It continues at 09N46W to just west of another tropical wave axis at 09N58W, then a short segment resumes just west of same wave, and continues to coast of South America near 09N62W. Besides the convection described above in the tropical wave section, scattered moderate to strong convection is seen 30 nm of line from 09N14W to 09N20W. Scattered moderate to isolated strong convection is within 180 nm south of the trough axis between 22W and 29W. Scattered moderate convection is within 120 nm south of the axis between 29W and 31W. ...DISCUSSION... GULF OF MEXICO... A surface ridge axis extends from the Atlantic to the NE Gulf of Mexico along 28N. A trough extends from northeast Florida southwest to near 28N88W. The combination of mid-level energy, and already available instability across the northeast Gulf has resulted in clusters of scattered moderate to isolated strong convection from 26N to 31N east of 88W. Widely scattered showers and isolated thunderstorms are noted from 26N to 31N between 88W and 90W. An upper anticyclone is noted on water vapor imagery to be centered over the far northern Gulf near 30N89W. The northeast flow east of the anticyclone is spreading high cirrus clouds from the convection southwest to near 25N89W. In the far southern portion of the Gulf, the leading edge of precipitation consisting of scattered moderate convection from Tropical Storm Earl extends northward to the Yucatan Channel and the eastern Bay of Campeche. This activity is forecast to gradually spread westward to the far southwest Gulf through Friday night. Strong to near gale force east winds are in the eastern Bay of Campeche from the tight pressure gradient associated with Tropical Storm Earl. These winds are forecast to decrease late Friday into Saturday. CARIBBEAN SEA... Tropical Storm Earl is inland and weakening over northern Guatemala early this afternoon. See Special Features section above. Water vapor imagery shows that a large envelop of very deep moisture trailing behind Earl, and covers the entire western Caribbean, and much of the central portion of the basin. This moisture is within a broad area of low pressure as noted in the 12 UTC surface analysis. Scattered moderate convection, some in clusters, is seen within these areas. Scattered moderate to isolated strong convection is just entering the far northeast portion of the sea in association with the approaching tropical wave described above. The pressure gradient throughout supports 15 to 25 kt trade winds, with the high end of this range confined to the north-central and northwest portions of the sea. ...HISPANIOLA... An upper level low is just north of Hispaniola, however limited moisture in the surrounding environment is only allowing for isolated showers and possible weak isolated thunderstorms to exist near its north coast. The upper low is forecast to move west and weaken over the next 48 hours. There is some opportunity for scattered showers and isolated thunderstorms to over the island this afternoon with ongoing daytime heating. ATLANTIC OCEAN... A cold front is along west of 75W while shortwave energy is moving eastward over the southeastern U.S. Scattered moderate convection is observed within 120 nm s of the front. This activity is forecast to persist through Friday. a large upper anticyclone is seen over the central Atlantic near24N50W. The flow pattern between the anticyclone and the upper low just north of Hispaniola near 22N71W is keeping a very moist upper flow between the tropical wave along 21N57W to 09N58W and the low. Upper level moisture associated with convection from the wave is spreading north to near 26N between 56W and 63W in the form of broken cirrus clouds. Elsewhere...dry air aloft is keeping stable conditions with only possible isolated showers and thunderstorms west of 56W. The convection associated with the tropical waves will translate westward across the far southern portions of the basin during the next 48 hours. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre