je.st
news
Tag: discussion
Tropical Storm Melissa Forecast Discussion Number 12
2019-10-14 10:31:15| National Hurricane Center (Atlantic)
Issued at 500 AM AST Mon Oct 14 2019 000 WTNT44 KNHC 140831 TCDAT4 Tropical Storm Melissa Discussion Number 12 NWS National Hurricane Center Miami FL AL142019 500 AM AST Mon Oct 14 2019 Melissa is hanging on to tropical storm status. Satellite images indicate that an area of deep convection continues to pulse in the northeastern quadrant of the circulation, but the remainder of the cyclone consists of a swirl of low-level clouds. The center of Melissa is losing definition as it is becoming increasingly elongated from northeast to southwest due to the interaction with a front about 90 n mi to its northwest. An ASCAT-C pass from around 0100 UTC showed maximum winds of about 35 kt in the southeastern quadrant, and the initial intensity is held at that value. This wind speed estimate is a little higher than the Dvorak estimates. Melissa is expected to remain in hostile conditions of strong westerly wind shear and dry mid-level air, and it is headed for progressively cooler waters. These conditions should promote weakening and ultimately dissipation within a day or two. Although the official forecast doesn't show Melissa dissipating until 36 hours, most of the models show the storm opening up into a trough later today, so it could certainly dissipate sooner than forecast. The tropical storm is moving east-northeastward at 17 kt. An even faster east-northeast to east motion is expected until the cyclone dissipates as it moves within the mid-latitude westerlies. The NHC track forecast lies near the middle of the tightly-packed guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 14/0900Z 40.7N 54.0W 35 KT 40 MPH 12H 14/1800Z 41.2N 50.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 24H 15/0600Z 41.5N 43.7W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 15/1800Z...DISSIPATED $$ Forecaster Cangialosi
Tags: number
discussion
storm
tropical
Tropical Storm Melissa Forecast Discussion Number 11
2019-10-14 04:45:48| National Hurricane Center (Atlantic)
Issued at 1100 PM AST Sun Oct 13 2019 000 WTNT44 KNHC 140245 TCDAT4 Tropical Storm Melissa Discussion Number 11 NWS National Hurricane Center Miami FL AL142019 1100 PM AST Sun Oct 13 2019 Deep convection associated with Melissa has continued to decrease in coverage this evening, and the system has become an exposed swirl of low- to mid-level clouds. The initial intensity has been held at 35 kt, which is in agreement with the latest TAFB Dvorak current intensity (CI) number and recent ASCAT data that revealed some 30-kt winds well southeast of the center. Strong westerly vertical wind shear and cool SSTs along the path of storm is expected to cause weakening, and Melissa should degenerate into a remnant low later tonight or early Monday. The global models indicate that the post-tropical cyclone will be absorbed by a frontal boundary in 2 to 3 days. Melissa is moving east-northeastward or 075/16 kt. There has been no change to the previous track forecast reasoning. Melissa should accelerate east-northeastward to eastward during the next day or two as it remains embedded within the mid-latitude westerly flow. The updated NHC track forecast is similar to the previous advisory, and near the middle of the tightly clustered guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 14/0300Z 40.2N 56.7W 35 KT 40 MPH 12H 14/1200Z 40.8N 53.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 24H 15/0000Z 41.5N 47.1W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 15/1200Z 41.7N 40.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 16/0000Z...DISSIPATED $$ Forecaster Brown
Tags: number
discussion
storm
tropical
Tropical Storm Melissa Forecast Discussion Number 10
2019-10-13 22:40:39| National Hurricane Center (Atlantic)
Issued at 500 PM AST Sun Oct 13 2019 000 WTNT44 KNHC 132040 TCDAT4 Tropical Storm Melissa Discussion Number 10 NWS National Hurricane Center Miami FL AL142019 500 PM AST Sun Oct 13 2019 After an earlier flare-up of convection, thunderstorm activity has decreased significantly in both coverage and intensity during the past 4 hours. Convection is now limited to a small area in the northeastern quadrant, and the inner-core region is becoming dominated by stable cold-air stratocumulus clouds. The initial intensity has been lowered to 35 kt based on 1400Z ASCAT wind data showing 35-36 kt wind vectors in the southern semicircle and subsequent erosion of the convective pattern. Melissa continues to gradually accelerate east-northeastward and the initial motion estimate is now 075/16 kt. An additional increase in forward speed, in conjunction with a turn toward the east, is expected by tonight and then continue through the remainder of the forecast period. The new NHC track forecast is similar to the previous advisory track, and lies near an average of the tightly packed consensus models TVCN, HCCA, and FSSE. The unfavorable combination of westerly vertical wind shear of more than 30 kt and SSTs less than 24 deg C is expected to continue the current weakening trend, with Melissa becoming a remnant low by Monday morning. The cyclone is forecast to merge or interact with a larger extratropical low by Wednesday and dissipate. The new official intensity forecast is similar to the previous advisory, and closely follows a blend of the HCCA, FSSE, and IVCN intensity consensus models. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 39.9N 58.8W 35 KT 40 MPH 12H 14/0600Z 40.5N 55.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 24H 14/1800Z 41.4N 50.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 15/0600Z 41.9N 43.6W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 15/1800Z 41.7N 37.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 16/1800Z...DISSIPATED $$ Forecaster Stewart
Tags: number
discussion
storm
tropical
Tropical Storm Melissa Forecast Discussion Number 9
2019-10-13 16:34:37| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Sun Oct 13 2019 000 WTNT44 KNHC 131434 TCDAT4 Tropical Storm Melissa Discussion Number 9 NWS National Hurricane Center Miami FL AL142019 1100 AM AST Sun Oct 13 2019 After an overnight convective hiatus, likely due to Melissa passing over a narrow band of cold water, deep convection has increased near the center and a curved band of broken convection has developed in the eastern semicircle. A 12Z TAFB shear pattern satellite intensity estimate resulted in 45 kt while the curved band pattern produced 35 kt. An average of these estimates yields 40 kt, which is close to the most recent UW-CIMSS SATCON and ADT estimates of 44 kt and 43 kt, respectively. Therefore, the initial intensity remains at 40 kt. Melissa is beginning to accelerate east-northeastward and the initial motion estimate is now 075/15 kt. A further increase in forward speed combined with an eastward motion is expected over the next couple of days as Melissa moves around the northern periphery of the deep-layer Bermuda-Azores high. By late Tuesday and Wednesday, Melissa is forecast to turn toward the east-southeast as a weakening extratropical low pressure system. The new NHC track forecast was nudged a little to the right of the previous advisory, and lies near the middle of the tightly-packed consensus guidance envelope. The westerly wind shear across Melissa is currently around 20 kt and the cyclone is moving over sub-25 degree C sea-surface temperatures (SST). Water temperatures ahead of the cyclone are forecast to decrease to 21-22 deg C within 12 hours, while the shear is expected to increase to 25-30 kt. The combination of these two negative factors will result in weakening by this evening, which will continue throughout the remainder of the forecast period, with Melissa becoming a post-tropical remnant by Monday and merging with a frontal system or larger extratropical low by Wednesday. The new official intensity forecast is similar to the previous advisory, and closely follows a blend of the HCCA and IVCN intensity models. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 39.8N 60.9W 40 KT 45 MPH 12H 14/0000Z 40.5N 57.7W 35 KT 40 MPH 24H 14/1200Z 41.4N 53.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 15/0000Z 41.9N 47.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 15/1200Z 41.8N 41.9W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 16/1200Z...DISSIPATED $$ Forecaster Stewart
Tags: number
discussion
storm
tropical
Tropical Storm Melissa Forecast Discussion Number 8
2019-10-13 10:32:03| National Hurricane Center (Atlantic)
Issued at 500 AM AST Sun Oct 13 2019 000 WTNT44 KNHC 130831 TCDAT4 Tropical Storm Melissa Discussion Number 8 NWS National Hurricane Center Miami FL AL142019 500 AM AST Sun Oct 13 2019 Satellite images indicate that Melissa has lost organization overnight. Deep convection separated from the low-level center a little before 0000 UTC, and now its convection is confined to a new area about 50 n mi north and northeast of the center. This degraded appearance in the cyclone's structure is due to about 20 kt of westerly vertical wind shear and dry mid-level air. An ASCAT pass from around 0200 UTC showed maximum winds in the 40 to 45 kt range, but since the convective pattern has degraded since then, the initial wind speed is lowered to 40 kt. This estimate is also near an average of the Dvorak FT and CI numbers from TAFB. The westerly shear is expected to increase even more during the next couple of days. These hostile winds aloft combined with the continued influence of dry and stable air should cause continued weakening, and Melissa is forecast to degenerate to a remnant low in about 24 hours, when it is forecast to be over SSTs below 22 C. The global models show the remnants of Melissa becoming absorbed or merging with a front in 2 to 3 days. Melissa has moved a little to the north of the previous track, with the initial motion now estimated to be 065/12 kt. The steering pattern is expected to become more zonal during the next couple of days, which should cause Melissa to move generally eastward at increasing forward speeds before it is absorbed within the frontal zone. The official track forecast is adjusted a little to the north of the previous one to account for the initial motion and position. This forecast lies near the middle of the tightly-packed guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 39.3N 62.6W 40 KT 45 MPH 12H 13/1800Z 40.2N 59.9W 35 KT 40 MPH 24H 14/0600Z 41.1N 55.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 14/1800Z 42.0N 50.2W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 15/0600Z 42.3N 44.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 16/0600Z...DISSIPATED $$ Forecaster Cangialosi
Tags: number
discussion
storm
tropical
Sites : [317] [318] [319] [320] [321] [322] [323] [324] [325] [326] [327] [328] [329] [330] [331] [332] [333] [334] [335] [336] next »