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Tropical Depression Four-E Forecast Discussion Number 3

2019-07-13 10:32:56| National Hurricane Center (East Pacific)

Issued at 300 AM MDT Sat Jul 13 2019 000 WTPZ44 KNHC 130832 TCDEP4 Tropical Depression Four-E Discussion Number 3 NWS National Hurricane Center Miami FL EP042019 300 AM MDT Sat Jul 13 2019 The depression has a ragged and sheared appearance. The low-level center briefly became exposed several hours ago before a burst of deep convection developed over the southwestern semicircle. The subjective satellite intensity estimates continue to support a 30-kt system, which is the initial intensity for this advisory. The convective maximum over warm SSTs will likely maintain this current increase in the convection through mid morning. Thereafter, the circulation is expected to entrain stable air to its west while continuing to be impacted by 20 kt of northeasterly shear. This should cause a weakening trend to begin later on today or tonight. By Sunday, the system is expected to become a remnant low devoid of deep convection. Shortly thereafter, the low will degenerate into a trough. The official intensity forecast is in agreement with all available intensity guidance, with just some minor variations in timing noted between the model solutions. The current motion is 305/13 kt. The aforementioned exposed center allowed for a northeastward adjustment of the cyclone's position over the past 12 hours or so. This northwestward motion is expected to continue while the system maintains its convection. Once the convection dissipates, the system will become steered more toward the west-northwest to west in the lower-level steering flow. The latest forecast track is very near the previous official forecast and is near the track model consensus. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 16.8N 109.7W 30 KT 35 MPH 12H 13/1800Z 17.6N 111.6W 30 KT 35 MPH 24H 14/0600Z 18.0N 114.1W 25 KT 30 MPH 36H 14/1800Z 18.3N 116.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 15/0600Z...DISSIPATED $$ Forecaster Latto/Cangialosi

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Tropical Storm Barry Forecast Discussion Number 11

2019-07-13 04:47:20| National Hurricane Center (Atlantic)

Issued at 1000 PM CDT Fri Jul 12 2019 179 WTNT42 KNHC 130247 TCDAT2 Tropical Storm Barry Discussion Number 11 NWS National Hurricane Center Miami FL AL022019 1000 PM CDT Fri Jul 12 2019 The overall satellite presentation of Barry has improved since this afternoon. The center is located closer to the main convective mass and there has been some expansion of the cirrus outflow. There has also been an increase in the convective banding over the eastern and southeastern portions of the circulation. Both NOAA and Air Force Reserve reconnaissance aircraft have been in the storm this evening. The NOAA aircraft found peak 700 mb flight-level winds of 64 kt in the southeastern quadrant, which still supports an initial intensity of 55 kt. Barry has been able to strengthen over the past day or so despite northerly shear and dry mid-level air. With the recent increase in convection near the center and the expansion of the upper-level outflow, it appears that the shear over the center has decreased. As a result, the NHC intensity forecast calls for Barry to become a hurricane before it reaches the coast of Louisiana. Although this is slightly above the intensity guidance, most of the dynamical models show some modest deepening before landfall. After the center moves inland, steady weakening is expected and the system is predicted to become a remnant low in about 72 hours. Barry has been meandering over the past several hours, but the longer term motion is 300/3 kt. The storm is expected to turn northwestward overnight as a weakness develops in the subtropical ridge that extends over the southeastern United States. This should bring the center of the storm onshore along the south-central coast of Louisiana on Saturday. By Saturday night or early Sunday, Barry is forecast to turn northward around the western portion of the aforementioned ridge. Barry or its remnants should recurve into the mid-latitude westerlies by late Monday. Although the guidance envelope has shifted slightly westward again this cycle, the NHC track is virtually unchanged and is closest to the typically reliable GFS and ECMWF models which lie along the eastern side of the envelope. 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 on Saturday. 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 13/0300Z 28.6N 91.0W 55 KT 65 MPH 12H 13/1200Z 29.3N 91.5W 65 KT 75 MPH 24H 14/0000Z 30.4N 92.1W 50 KT 60 MPH...INLAND 36H 14/1200Z 31.5N 92.4W 35 KT 40 MPH...INLAND 48H 15/0000Z 32.9N 92.5W 25 KT 30 MPH...INLAND 72H 16/0000Z 35.8N 92.4W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 17/0000Z 38.7N 90.2W 15 KT 15 MPH...POST-TROP/REMNT LOW 120H 18/0000Z...DISSIPATED $$ Forecaster Brown

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Tropical Depression Four-E Forecast Discussion Number 2

2019-07-13 04:34:26| National Hurricane Center (East Pacific)

Issued at 900 PM MDT Fri Jul 12 2019 000 WTPZ44 KNHC 130234 TCDEP4 Tropical Depression Four-E Discussion Number 2 NWS National Hurricane Center Miami FL EP042019 900 PM MDT Fri Jul 12 2019 The depression looks less organized than a few hours ago, with the apparent low-level center displaced a fair distance from the mid-level circulation to the southwest. In addition, deep convection has decreased markedly during that time, although a new burst is forming in the southwestern quadrant. The initial wind speed is kept 30 kt in agreement with the latest Dvorak estimates. The cyclone probably only has the convective maximum period overnight to become a tropical storm before a combination of strong shear, cooling SSTs, and upper-level convergence start a steady weakening. In fact, the depression is forecast by all of the dynamical guidance to lose deep convection near or just after 24 hours. Thus, the NHC intensity forecast is lowered 5 kt from the previous one, similar to the consensus, and the remnant low timing is pushed up to 36h as well. An uncertain motion is 300/11 kt. A low- to mid-level ridge to the north of the cyclone should gradually turn the depression westward during the next couple of days with a slight increase in forward speed. Models have come into better agreement on the track of the depression, not too far from the previous NHC track prediction, so the new forecast is basically the same as the previous one. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 15.8N 108.5W 30 KT 35 MPH 12H 13/1200Z 16.7N 110.1W 30 KT 35 MPH 24H 14/0000Z 17.5N 112.4W 25 KT 30 MPH 36H 14/1200Z 17.9N 114.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 15/0000Z 18.0N 117.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 16/0000Z...DISSIPATED $$ Forecaster Blake

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Tropical Storm Barry Forecast Discussion Number 10

2019-07-12 22:39:20| National Hurricane Center (Atlantic)

Issued at 400 PM CDT Fri Jul 12 2019 000 WTNT42 KNHC 122039 TCDAT2 Tropical Storm Barry Discussion Number 10 NWS National Hurricane Center Miami FL AL022019 400 PM CDT Fri Jul 12 2019 Although the storm continues to look disorganized in satellite imagery, surface observations and data from an Air Force Reserve Hurricane Hunter aircraft indicate that the central pressure has fallen to 993 mb with the maximum winds still near 55 kt. A prominent cloud swirl has rotated more than halfway around the eastern and northern side of the mean center since 17Z, and there were several reports of strong winds in association with this feature. Strong convection persists to the south of the center, but to this point northerly shear has prevented the convection from becoming better organized. The initial motion is now an erratic 300/5. Barry should turn northwestward during the next several hours as it approaches a weakness in the mid-level ridge over the Mississippi Valley, and this motion should bring the center across the central coast of Louisiana between 12-24 h. After landfall, the system should move northward through a break in the ridge until the 72 h point, after which it should recurve northeastward into the westerlies. The guidance envelope has shifted slightly westward since the last advisory, but the shift is not large enough to require significant changes to the forecast track. Thus, the new track forecast again has only minor tweaks from the previous one, and it lies just east of the the various consensus models. Barry continues to strengthen despite the asymmetric convective structure, the shear, and the presence of mid- to upper-level dry air over the northern semicircle. The intensity guidance forecasts continued intensification until landfall, and so will the NHC forecast. While not explicitly shown in the forecast, Barry is expected to become a hurricane near the time it makes landfall between the 12 and 24 h forecasts points. After landfall, the cyclone should steadily weaken, with decay to a remnant low expected to occur in about 72 h and dissipation after 96 h. 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 are already beginning to rise in these areas, with the peak inundation expected on Saturday. 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 12/2100Z 28.7N 90.9W 55 KT 65 MPH 12H 13/0600Z 29.2N 91.3W 60 KT 70 MPH 24H 13/1800Z 30.1N 91.9W 60 KT 70 MPH...INLAND 36H 14/0600Z 31.3N 92.3W 45 KT 50 MPH...INLAND 48H 14/1800Z 32.5N 92.5W 30 KT 35 MPH...INLAND 72H 15/1800Z 35.0N 92.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 16/1800Z 38.0N 91.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 17/1800Z...DISSIPATED $$ Forecaster Beven

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Tropical Depression Four-E Forecast Discussion Number 1

2019-07-12 22:30:48| National Hurricane Center (East Pacific)

Issued at 300 PM MDT Fri Jul 12 2019 000 WTPZ44 KNHC 122030 TCDEP4 Tropical Depression Four-E Discussion Number 1 NWS National Hurricane Center Miami FL EP042019 300 PM MDT Fri Jul 12 2019 Convection associated with an area of low pressure located south of the southwestern coast of Mexico has increased substantially since last night. Furthermore, ASCAT data from 1630 UTC show that the low has developed a small but well-defined center with maximum winds of 25-30 kt. The system now meets the criteria for a tropical cyclone, and advisories have been initiated on Tropical Depression Four-E. The initial intensity is 30 kt, based on the ASCAT data. The depression is being sheared by strong upper-level easterly winds and is not expected to last long. In fact all of the dynamical models suggest that the depression will weaken and become a post-tropical low in about 36 h, if not sooner. The statistical guidance is a little higher, but still generally agrees that the depression will not strengthen much. The official forecast shows the cyclone becoming a short-lived tropical storm and then slowly weakening through 48 h, and is generally close to IVCN. The depression is moving west-northwestward, or 290/11 kt along the southwestern periphery of a low- to mid-level ridge. There is surprisingly little agreement in the track guidance on the track of the depression for the brief period it survives, but they all generally show it moving near its current heading for a day or so. A turn toward the west is expected by Sunday as the cyclone weakens and becomes shallow. I have no reason to favor any one solution over another at this point, so the NHC forecast closely follows the consensus at all forecast times. FORECAST POSITIONS AND MAX WINDS INIT 12/2100Z 15.1N 107.5W 30 KT 35 MPH 12H 13/0600Z 16.0N 109.0W 35 KT 40 MPH 24H 13/1800Z 17.1N 111.1W 30 KT 35 MPH 36H 14/0600Z 17.7N 113.3W 30 KT 35 MPH 48H 14/1800Z 18.1N 115.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 15/1800Z...DISSIPATED $$ Forecaster Zelinsky

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