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Tropical Storm Barry Forecast Discussion Number 12
2019-07-13 10:41:31| National Hurricane Center (Atlantic)
Issued at 400 AM CDT Sat Jul 13 2019 000 WTNT42 KNHC 130841 TCDAT2 Tropical Storm Barry Discussion Number 12 NWS National Hurricane Center Miami FL AL022019 400 AM CDT Sat Jul 13 2019 Barry continues to inch its way toward the Louisiana coast with some of the northern bands now moving across southeastern Louisiana. Satellite and radar imagery still indicate that the storm has an asymmetric structure with most of its deep convection located to the south and east of the center due to ongoing north-northwesterly shear. The convection has been expanding though, and some bands are starting to wrap around the northeastern side, which could indicate some decrease in shear. The initial intensity for this advisory is held at 55 kt, which is in agreement with recent ASCAT passes and a Dvorak classification from TAFB. Doppler radar velocities between 10000 and 12000 feet show winds of 60-67 kt, but based on surface observations and the ASCAT data these might not be mixing down to the surface. The Air Force Hurricane Hunters are scheduled to investigate Barry in a few hours and the data they collect should provide a better assessment of the storm's intensity. Barry continues its erratic motion toward the west-northwest. Smoothing through the wobbles yields an initial motion of 300/4 kt. A northwestward turn should occur soon, and the center is expected to cross the coast of south-central Louisiana within the next 6 to 12 hours. After that time, a turn toward the north-northwest and north is forecast as the cyclone moves inland over the Mississippi Valley toward a weakness in the ridge. The NHC track forecast is nudged a little to the west of the previous one, but it remains on the eastern side of the guidance envelope in best agreement with the GFS and ECMWF models. Although not explicitly shown in the forecast below, Barry is still expected to be a hurricane before it makes landfall later today. After landfall, steady weakening is expected and Barry is forecast to become a tropical depression in about 36 hours and degenerate into a remnant low in two to three days. The global models show the remnant low dissipating over the Ohio Valley in 3 or 4 days. The NHC intensity forecast is a little above the guidance in the short term, but in line with the consensus models after that. Key Messages: 1. There is a danger of life-threatening storm surge inundation along the coast of southern and southeastern Louisiana, portions of Lake Pontchartrain, and portions of coastal Mississippi where a Storm Surge Warning is in effect. Water levels have already begun to rise in these areas, with peak inundation expected to occur later today. The highest storm surge inundation is expected between Intracoastal City and Shell Beach. 2. The slow movement of Barry will result in a long duration heavy rainfall and flood threat along the central Gulf Coast, across portions of the Lower Mississippi Valley and north into the Tennessee Valley through the weekend into early next week. Flash flooding and river flooding will become increasingly likely, some of which may be life-threatening, especially across portions of southeast Louisiana into Mississippi. 3. Hurricane conditions are expected along a portion of the coast of Louisiana, where a Hurricane Warning is in effect. Tropical storm conditions are expected elsewhere along much of the Louisiana coast and inland across portions of the lower Mississippi Valley where tropical storm warnings are in effect. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 29.1N 91.8W 55 KT 65 MPH 12H 13/1800Z 29.8N 92.1W 60 KT 70 MPH...INLAND 24H 14/0600Z 30.9N 92.6W 45 KT 50 MPH...INLAND 36H 14/1800Z 32.3N 92.9W 30 KT 35 MPH...INLAND 48H 15/0600Z 33.8N 93.0W 25 KT 30 MPH...INLAND 72H 16/0600Z 36.5N 92.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 17/0600Z...DISSIPATED $$ Forecaster Cangialosi
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