Home › discussion
 

Keywords :   


Tag: discussion

Hurricane Delta Forecast Discussion Number 19

2020-10-09 10:45:29| National Hurricane Center (Atlantic)

Issued at 400 AM CDT Fri Oct 09 2020 297 WTNT41 KNHC 090845 TCDAT1 Hurricane Delta Discussion Number 19 NWS National Hurricane Center Miami FL AL262020 400 AM CDT Fri Oct 09 2020 Delta has been generally steady in strength during the past several hours as it starts to close in on the southwestern Louisiana coast. An eye has occasionally been evident in geostationary satellite images, and deep convection remains quite intense around that feature. The Air Force Hurricane Hunters recently found have been investigating Delta this morning, and recently reported maximum flight-level winds of 125 kt and peak SFMR surface winds of 99 kt. Based on a blend of this data, the initial intensity is held at 105 kt. The hurricane appears to be leveling off in strength as recent microwave passes show some asymmetry in the eyewall and vertical tilt due to southwesterly shear. The core of the hurricane passed very close to NOAA buoy 42002 a few hours ago, and the pressure at the buoy fell to 953 mb. The buoy also reported peak winds around 70 kt and a significant wave height of about 35 ft. The major hurricane is now moving northward at 10 kt. The track forecast models remain quite consistent. Delta is forecast to continue moving northward today and then turn north-northeastward tonight between a ridge over the western Atlantic and a trough over the south-central United States. This motion is expected to take the core of the hurricane to the Louisiana coast this evening. After landfall, a turn to the northeast is forecast as a larger trough moves eastward toward Delta, and that motion should continue until the cyclone dissipates over Tennessee or Kentucky in a few days. The models remain tightly clustered, and only minor tweaks were made to the previous NHC track forecast. Delta is expected to move over waters with progressively lower oceanic heat content as it approaches the Louisiana coast. These less favorable oceanic conditions combined with an increase in southwesterly shear should cause Delta to weaken a little before it moves onshore. Regardless, Delta is forecast to be near major hurricane intensity when it makes landfall and significant impacts are expected (see Key Messages below). After landfall, rapid weakening is anticipated and Delta is forecast to fall below hurricane strength tonight or early Saturday and dissipate in about 3 days. Key Messages: 1. Life-threatening storm surge is expected near and east of where Delta makes landfall this evening, and a Storm Surge Warning is in effect from High Island, Texas, to Ocean Springs, Mississippi. The highest inundation of 7 to 11 feet is expected somewhere between Rockefeller Wildlife Refuge and Morgan City, Louisiana. Residents in the warning area should promptly follow advice given by local officials. The storm surge risk remains high despite the forecast decrease in intensity before landfall since Delta is a relatively large hurricane. 2. Hurricane-force winds are expected this afternoon and evening somewhere within the Hurricane Warning area between High Island, Texas, and Morgan City, Louisiana. Hurricane force winds will also spread inland across portions of southern Louisiana near the path of Deltas center this evening and tonight. 3. Heavy rainfall will lead to significant flash flooding and minor to major river flooding in parts of Louisiana today and Saturday. Additional flooding is expected across portions of the central Gulf Coast into the Lower Mississippi Valley. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 26.9N 93.7W 105 KT 120 MPH 12H 09/1800Z 28.6N 93.3W 95 KT 110 MPH 24H 10/0600Z 31.1N 92.3W 60 KT 70 MPH...INLAND 36H 10/1800Z 32.9N 91.0W 30 KT 35 MPH...INLAND 48H 11/0600Z 34.2N 89.1W 25 KT 30 MPH...INLAND 60H 11/1800Z 35.6N 87.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 12/0600Z...DISSIPATED $$ Forecaster Cangialosi

Tags: number discussion delta forecast

 

Tropical Depression Norbert Forecast Discussion Number 15

2020-10-09 10:38:30| National Hurricane Center (East Pacific)

Issued at 300 AM MDT Fri Oct 09 2020 089 WTPZ44 KNHC 090838 TCDEP4 Tropical Depression Norbert Discussion Number 15 NWS National Hurricane Center Miami FL EP192020 300 AM MDT Fri Oct 09 2020 Norbert is clearly struggling to remain a tropical depression. The low-level center is exposed in recent satellite imagery, likely due to a combination of east-southeasterly vertical wind shear and dry mid-level air in the surrounding environment. The nearest deep convection is located roughly 50 miles south of the center, and it is very poorly organized. Unfortunately, overnight ASCAT passes missed the center of Norbert, but a partial overpass of the eastern semicircle revealed 20 kt winds. A blend of the UW-CIMSS objective estimate and the TAFB subjective Dvorak estimate supports an intensity of 25 kt, which may be generous given the lack of sustained convection near the cyclone's center. Vertical wind shear is taking its toll on Norbert, and the latest SHIPS guidance suggests the deep-layer shear will increase over the next 24-48 h. Thus, Norbert is unlikely to survive the five-day forecast period. If new convection doesn't develop soon, it could degenerate into a remnant low as early as today. The latest NHC forecast explicitly calls for dissipation by 72 h. Norbert is starting to drift northwestward, and this general motion should continue over the next couple of days as a weak mid-level ridge builds to the northeast of the depression. The NHC track forecast closely follows the consensus aids and remains very close to the previous forecast. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 13.2N 106.0W 25 KT 30 MPH 12H 09/1800Z 13.4N 106.3W 25 KT 30 MPH 24H 10/0600Z 13.9N 106.9W 25 KT 30 MPH 36H 10/1800Z 14.4N 107.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 11/0600Z 14.7N 107.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 60H 11/1800Z 14.9N 107.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 12/0600Z...DISSIPATED $$ Forecaster Reinhart/Zelinsky

Tags: number discussion tropical depression

 
 

Tropical Depression Norbert Forecast Discussion Number 14

2020-10-09 04:42:25| National Hurricane Center (East Pacific)

Issued at 900 PM MDT Thu Oct 08 2020 000 WTPZ44 KNHC 090242 TCDEP4 Tropical Depression Norbert Discussion Number 14 NWS National Hurricane Center Miami FL EP192020 900 PM MDT Thu Oct 08 2020 Norbert's satellite presentation has changed little in the past several hours. Intermittent bursts of deep convection continue to pulse near the center, and the depression's asymmetric appearance indicates it is still experiencing southeasterly shear. The initial intensity is held at 25 kt based on a T1.5 Dvorak classification from TAFB and earlier satellite-derived wind data. Environmental conditions are not expected to change much during the next several days. Norbert will remain over warm sea-surface temperatures, but weak to moderate east-southeasterly shear will likely persist over the cyclone. Little intensity change is expected over the next couple of days. The NHC intensity forecast keeps Norbert as a 25-kt tropical depression through the next 60 h, although minor intensity fluctuations are possible. Between 36-72 h, increasing deep-layer shear should expedite Norbert's degeneration into a remnant low, and this advisory calls for Norbert to become a remnant low at 72 h. Norbert has moved little in the past 6-12 h, as the large-scale steering currents remain weak. A weak mid-level ridge is forecast to build to the northeast of the cyclone Friday through Saturday, which should steer Norbert slowly west-northwestward or northwestward. A mid- to upper-level low is expected to move across northern Mexico on Sunday, which could cause Norbert to stall or meander once again if it remains a depression. Later in the forecast period, whatever remains of Norbert should move westward as it becomes embedded within the low-level easterly trades. The latest NHC track forecast is adjusted slightly towards the left of the previous forecast, in line with the latest model consensus. FORECAST POSITIONS AND MAX WINDS INIT 09/0300Z 13.0N 106.0W 25 KT 30 MPH 12H 09/1200Z 13.1N 106.3W 25 KT 30 MPH 24H 10/0000Z 13.5N 106.9W 25 KT 30 MPH 36H 10/1200Z 14.2N 107.4W 25 KT 30 MPH 48H 11/0000Z 14.6N 107.6W 25 KT 30 MPH 60H 11/1200Z 14.8N 107.7W 25 KT 30 MPH 72H 12/0000Z 15.0N 107.8W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 13/0000Z 15.0N 108.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 14/0000Z 15.0N 109.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Reinhart/Berg

Tags: number discussion tropical depression

 

Hurricane Delta Forecast Discussion Number 18

2020-10-09 04:37:20| National Hurricane Center (Atlantic)

Issued at 1000 PM CDT Thu Oct 08 2020 000 WTNT41 KNHC 090237 TCDAT1 Hurricane Delta Discussion Number 18 NWS National Hurricane Center Miami FL AL262020 1000 PM CDT Thu Oct 08 2020 Reports from Air Force and NOAA Hurricane Hunter aircraft investigating Delta indicate that the hurricane strengthened a little more this evening. Peak flight-level winds were 120 kt, and the highest SFMR-observed surface winds were 98 kt. Using a blend of adjusted flight-level and surface wind observations, the current intensity estimate is set at 105 kt. The eye became obscured on satellite images a couple of hours ago, but recently it has become apparent again. Delta could intensify a little more within the next 6 hours or so. Thereafter, sharply decreasing oceanic heat content, significantly increasing west-southwesterly shear, and drier mid-level air should cause weakening. The official intensity forecast through landfall is above most of the model guidance. However, even 24-hour tropical cyclone intensity forecasts are still subject to an uncertainty of 1 Saffir-Simpson category, so one should not focus on the exact official landfall intensity forecast. Moreover, even if Delta weakens some, it will still have serious storm surge impacts due to its large size. Aircraft and satellite center fixes show that the hurricane is gradually turning toward the right. The motion is now north-northwestward, or 340/10 kt. Delta should turn northward on Friday as it moves on the western side of a mid-tropospheric high pressure area. Later on Friday, a 500-mb shortwave trough over the southern United States is likely to cause the tropical cyclone to turn north-northeastward and cross the northern Gulf of Mexico coast. Delta should then move northeastward on the eastern side of the trough over the southeastern United States for the next day or two before dissipating near Kentucky. The official track forecast is very close to the previous NHC track, and in very good agreement with the various consensus track predictions. Key Messages: 1. Life-threatening storm surge is expected near and east of where Delta makes landfall Friday, and a Storm Surge Warning is in effect from High Island, Texas, to Ocean Springs, Mississippi. The highest inundation of 7 to 11 feet is expected somewhere between Rockefeller Wildlife Refuge and Morgan City, Louisiana. Residents in the warning area should promptly follow advice given by local officials. The storm surge risk remains high despite the forecast decrease in intensity before landfall since Delta is a relatively large hurricane. 2. Hurricane-force winds are expected Friday afternoon and evening somewhere within the Hurricane Warning area between High Island, Texas, and Morgan City, Louisiana. Hurricane force winds will also spread inland across portions of southern Louisiana near the path of Deltas center Friday evening and Friday night. 3. Heavy rainfall will lead to significant flash flooding and minor to major river flooding in parts of Louisiana Friday and Saturday. Additional flooding is expected across portions of the central Gulf Coast into the Lower Mississippi Valley. FORECAST POSITIONS AND MAX WINDS INIT 09/0300Z 25.7N 93.6W 105 KT 120 MPH 12H 09/1200Z 27.4N 93.7W 105 KT 120 MPH 24H 10/0000Z 29.8N 93.0W 85 KT 100 MPH...INLAND 36H 10/1200Z 32.0N 91.9W 45 KT 50 MPH...INLAND 48H 11/0000Z 33.5N 90.2W 25 KT 30 MPH...INLAND 60H 11/1200Z 34.9N 88.4W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 12/0000Z 36.5N 87.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 13/0000Z...DISSIPATED $$ Forecaster Pasch/Berg

Tags: number discussion delta forecast

 

Hurricane Delta Forecast Discussion Number 17

2020-10-08 23:00:24| National Hurricane Center (Atlantic)

Issued at 400 PM CDT Thu Oct 08 2020 000 WTNT41 KNHC 082100 TCDAT1 Hurricane Delta Discussion Number 17 NWS National Hurricane Center Miami FL AL262020 400 PM CDT Thu Oct 08 2020 Delta is strengthening. In satellite imagery, an eye is now seen in the cold cloud tops of the central dense overcast. On the aircraft side, just received reports from an Air Force Reserve Hurricane Hunter aircraft included 700-mb flight-level winds of 119 kt, SFMR winds estimates near 90 kt, and a central pressure of 959 mb inside a 30 n mi wide eye. A blend of the flight-level and SFMR wind estimates give an initial intensity of 100 kt, and Delta is again a major hurricane. The initial motion is now northwestward or 320/10 kt. There is no change to the track forecast philosophy and little change to the track forecast from the previous advisory. During the next 12-24 h, Delta should turn to the north between a mid- to upper-level ridge over the Florida Peninsula and eastern Gulf of Mexico and a mid- to upper-level level trough over the U.S. Southern Plains. This should be followed by a north-northeastward motion that is expected to bring the center near or over the northern Gulf coast, most likely in southwestern Louisiana, in about 30 h. After landfall, the cyclone should move northeastward through the Lower Mississippi and Tennessee Valleys along the southern edge of the mid-latitude westerlies until it dissipates. The track guidance remains very tightly clustered in terms of direction, and the new forecast track is near the various consensus models. Shear, sea surface temperature, and moisture conditions appear favorable for strengthening during the next 12 h or so, and based on this additional intensification is expected tonight. A short period of rapid intensification remains possible given current trends, although the various rapid intensification indices are not enthusiastic about the possibilities of this, After 12 h, the global models again forecast strong southwesterly shear developing over the hurricane before landfall, and based on this some weakening is forecast. Rapid weakening is expected after landfall. The system is expected to weaken to a depression no later than 60 h and degenerate to a remnant low by 72 h, with dissipation following shortly thereafter. The intensity forecast lies at or above the upper edge of the intensity guidance. Recent scatterometer data indicates that Delta is growing in size as it approaches the Louisiana coast. The NHC wind radii forecast again follows a combination of the data and the forecasts from global and hurricane regional models. Key Messages: 1. Life-threatening storm surge is expected near and east of where Delta makes landfall Friday, and a Storm Surge Warning is in effect from High Island, Texas, to Ocean Springs, Mississippi. The highest inundation of 7 to 11 feet is expected somewhere between Rockefeller Wildlife Refuge and Morgan City, Louisiana. Residents in the warning area should promptly follow advice given by local officials. The storm surge risk remains high despite the forecast decrease in intensity before landfall since Delta is expected to grow in size. 2. Hurricane-force winds are expected Friday afternoon and evening somewhere within the Hurricane Warning area between High Island, Texas, and Morgan City, Louisiana. Hurricane force winds will also spread inland across portions of southern Louisiana near the path of Deltas center Friday evening and Friday night. 3. Heavy rainfall will lead to significant flash flooding and minor to major river flooding in parts of Louisiana Friday and Saturday. Additional flooding is expected across portions of the central Gulf Coast into the Lower Mississippi Valley. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 24.8N 93.4W 100 KT 115 MPH 12H 09/0600Z 26.3N 93.9W 110 KT 125 MPH 24H 09/1800Z 28.6N 93.5W 105 KT 120 MPH 36H 10/0600Z 31.0N 92.5W 65 KT 75 MPH...INLAND 48H 10/1800Z 32.9N 91.1W 40 KT 45 MPH...INLAND 60H 11/0600Z 34.3N 89.2W 30 KT 35 MPH...INLAND 72H 11/1800Z 35.8N 87.2W 20 KT 25 MPH...POST-TROP/INLAND 96H 12/1800Z...DISSIPATED $$ Forecaster Beven

Tags: number discussion delta forecast

 

Sites : [152] [153] [154] [155] [156] [157] [158] [159] [160] [161] [162] [163] [164] [165] [166] [167] [168] [169] [170] [171] next »