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Tropical Storm Barry Forecast Discussion Number 6
2019-07-11 22:59:05| National Hurricane Center (Atlantic)
Issued at 400 PM CDT Thu Jul 11 2019 000 WTNT42 KNHC 112058 TCDAT2 Tropical Storm Barry Discussion Number 6 NWS National Hurricane Center Miami FL AL022019 400 PM CDT Thu Jul 11 2019 Barry has become a little better organized since the last advisory, with a convective band forming closer to the center in the southern semicircle and the central pressure falling to near 1003 mb. However, the strongest winds are still 70 nm or more from the center, and there are several cloud swirls rotating around the mean center. The initial intensity remains 35 kt based on earlier aircraft and scatterometer data, but it is possible this is a little conservative. The initial motion is 275/4. Barry is being steered by a weak low- to mid-level ridge to the north, and a weakness in the ridge is forecast to develop during the next 24-48 h. This should allow the cyclone to turn northwestward and eventually northward. However, there remains a large spread in the track guidance. The HWRF and HMON forecast Barry to move generally northward across southeastern Louisiana, while the UKMET and the UKMET ensemble mean take the cyclone to the upper Texas coast. The GFS, ECMWF, and Canadian models lie between these extremes. There was a slight westward shift in the guidance envelope since the last advisory, which resulted in the consensus models being close to the previous NHC forecast track. As a result, the new forecast track is similar to the previous track, and it calls for the center of Barry to make landfall on the central Louisiana coast between 36-48 h. After 72 h, the cyclone should recurve northeastward as it enters the mid-latitude westerlies. Barry is still being affected by northerly shear, and GOES-16 airmass imagery indicates mid- to upper-level dry air coming from the northeast has spread over the low-level center. So far, this has not stopped the development, and the guidance is in good agreement that intensification will continue. Thus, the new intensity forecast is similar to the previous one in calling for intensification until landfall. While not explicitly shown in the forecast, there is a significant chance that Barry will be a hurricane when it makes landfall between 36-48 h in agreement with the HWRF and GFS models. After landfall, Barry should weaken as it moves through the Mississippi Valley, and it is forecast to become a remnant low by 96 h. Key Messages: 1. There is a danger of life-threatening storm surge inundation along the coast of southern and southeastern Louisiana where a Storm Surge Warning is in effect. The highest storm surge inundation is expected between the Mouth of the Atchafalaya River and Shell Beach. Residents in these areas should listen to any advice given by local officials. 2. The slow movement of Barry will result in a long duration heavy rainfall and flood threat along the central Gulf Coast and inland through the lower Mississippi Valley through the weekend into early next week. Flash flooding and river flooding will become increasingly likely, some of which may be significant, especially along and east of the track of the system. 3. Hurricane conditions are expected along a portion of the coast of Louisiana, where a Hurricane Warning has been issued. Residents in these areas should rush their preparations to completion, as tropical storm conditions are expected to arrive in the warning area by Friday morning. FORECAST POSITIONS AND MAX WINDS INIT 11/2100Z 27.8N 89.3W 35 KT 40 MPH 12H 12/0600Z 27.9N 89.8W 45 KT 50 MPH 24H 12/1800Z 28.3N 90.5W 50 KT 60 MPH 36H 13/0600Z 29.0N 91.3W 60 KT 70 MPH 48H 13/1800Z 30.0N 91.7W 60 KT 70 MPH...INLAND 72H 14/1800Z 32.5N 92.0W 30 KT 35 MPH...INLAND 96H 15/1800Z 35.0N 91.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 16/1800Z 37.5N 89.0W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Beven
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