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Tropical Depression Fred Forecast Discussion Number 14
2021-08-13 04:52:38| National Hurricane Center (Atlantic)
Issued at 1100 PM EDT Thu Aug 12 2021 464 WTNT41 KNHC 130252 TCDAT1 Tropical Depression Fred Discussion Number 14 NWS National Hurricane Center Miami FL AL062021 1100 PM EDT Thu Aug 12 2021 Data from an Air Force Reserve reconnaissance aircraft this indicate that Fred's inner-core wind field Fred remains poorly organized. Also, data from a NOAA reconnaissance aircraft suggests that the 650-mb mid-level circulation center is titled at least 40 nmi to the east of the low-level center. The maximum 925-mb flight-level wind measured thus far has been 43 kt and the highest reliable SFMR surface wind speed sampled has been 33 kt. A blend of these data support maintaining a solid 30-kt intensity for this advisory, but Fred is right on the cusp of regaining tropical storm status. Fred has slowed down some more, with the initial motion estimate an uncertain 295/08 kt. The uncertainty in Fred's forward motion is related to the speed due to the low-level center jumping around every time a small convective tower develops within the larger cloud mass. However, the general motion of the wind field and the associated pressure envelope is toward the west-northwest or 295 degrees. Otherwise, there is no significant changes to the previous track forecast or reasoning. Fred is expected to continue moving west-northwestward along the southwestern periphery of a deep-layer for the next 36 hours or so, followed by a northwestward motion near or just offshore the Florida west coast in the 48-to-72-hour period. On days 4 and 5, a slower northward motion is forecast as Fred moves into a developing weakness in the ridge. The latest track guidance has become more divergent, with the GFS model dissipating and then redeveloping Fred over south Florida in about 48 hours, with the other models taking a weakening cyclone more westward. The exception is the westward-trending ECMWF model, which moves Fred along the Florida west coast. The new NHC track forecast was nudged slightly to the east or right of the previous advisory track after 24 hours, but lies to the left of the ECMWF model and between the NOAA-HCCA and TVCA consensus track models. Fred is forecast to remain under the influence of westerly to southwesterly vertical wind shear for the next 72 hours. It is the magnitude of the shear that is in question. The GFS maintains 15-20 kt of shear for the next three days, whereas the ECMWF model decreases the shear to around 10 kt in the 24-to-60-hour period, with the latter scenario favoring some strengthening if Fred doesn't interact too much with the Florida peninsula. Due to the uncertainty in the amount of shear and land interaction that will be encountered, latest official intensity forecast remains similar to the previous advisory and a blend of the HCCA and TVCA consensus model intensity forecasts. KEY MESSAGES: 1. From Friday into Monday, heavy rainfall could lead to areal, urban, small stream, and exacerbated river flooding, across southern and central Florida, and into the Big Bend of Florida. By early next week, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont. 2. Tropical storm conditions are possible beginning Friday night and Saturday in the Florida Keys and portions of southern Florida, where a Tropical Storm Watch is in effect. The risk of tropical storm conditions will spread northward along portions of the Florida west coast and to the Florida Panhandle Saturday night through Monday. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 21.5N 75.6W 30 KT 35 MPH 12H 13/1200Z 22.2N 77.1W 35 KT 40 MPH 24H 14/0000Z 23.0N 79.0W 35 KT 40 MPH 36H 14/1200Z 24.2N 80.6W 40 KT 45 MPH 48H 15/0000Z 25.5N 82.1W 40 KT 45 MPH 60H 15/1200Z 27.2N 83.1W 45 KT 50 MPH 72H 16/0000Z 29.1N 84.2W 45 KT 50 MPH 96H 17/0000Z 31.8N 85.6W 35 KT 40 MPH...INLAND 120H 18/0000Z 34.4N 85.5W 25 KT 30 MPH...INLAND $$ Forecaster Stewart
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Tropical Depression Fred Forecast Discussion Number 13
2021-08-12 22:54:03| National Hurricane Center (Atlantic)
Issued at 500 PM EDT Thu Aug 12 2021 000 WTNT41 KNHC 122053 TCDAT1 Tropical Depression Fred Discussion Number 13 NWS National Hurricane Center Miami FL AL062021 500 PM EDT Thu Aug 12 2021 Fred remains poorly organized at this time. While the low-level circulation looks more closed than it did earlier, the center is broad and may have multiple vortices rotating around it. Also, while convection has increased from earlier today, there is only minimal convection near the center and little evidence of banding. The initial intensity remains 30 kt, with those winds likely occurring in squalls to the northeast of the center. Fred has slowed its forward speed, with the initial motion now 295/10. There is little change to the track forecast philosophy from the previous advisory. The subtropical ridge to the northeast should steer Fred west-northwestward for the first 24-36 h, followed by a turn toward the northwest as the cyclone approaches the western periphery of the ridge. By 96-120 h, a northward motion is expected as Fred moves into a weakness in the ridge. The track guidance has shifted westward since the previous advisory, most notably after about 24 h. Thus, that portion of the new forecast track has also been nudged a little westward, but it still lies to the east of the various consensus models. Fred remains in an environment of about 20 kt of westerly vertical wind shear. The shear is expected to persist during the next day or so, and this combined with the current disorganization of the system should prevent significant strengthening during that time. After that, there remains disagreement between the global models on the evolution of the upper-level trough over Florida and the upper-level anticyclone southeast of Fred. Some shear is likely to continue, but there may be a period of more conducive conditions from 36-72 h. The new intensity forecast is similar to the previous one in calling for slow strengthening through the first 36 h, with a little faster strengthening from 36-72 h. With that being said, the forecast 45-kt peak intensity is near the high end of the intensity guidance. KEY MESSAGES: 1. From Friday into Monday, heavy rainfall could lead to areal, urban, small stream, and exacerbated river flooding across southern and central Florida, and into the Big Bend of Florida. By early next week, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont. 2. Tropical storm conditions are possible beginning Friday night and Saturday in the Florida Keys and portions of southern Florida, where a Tropical Storm Watch is in effect. The risk of tropical storm conditions will spread northward along portions of the Florida west coast and to the Florida Panhandle Saturday night through Monday. FORECAST POSITIONS AND MAX WINDS INIT 12/2100Z 21.3N 75.3W 30 KT 35 MPH 12H 13/0600Z 22.0N 77.0W 30 KT 35 MPH 24H 13/1800Z 23.0N 79.0W 30 KT 35 MPH 36H 14/0600Z 24.0N 80.6W 35 KT 40 MPH 48H 14/1800Z 25.2N 81.9W 35 KT 40 MPH 60H 15/0600Z 26.4N 83.1W 40 KT 45 MPH 72H 15/1800Z 28.1N 84.1W 45 KT 50 MPH 96H 16/1800Z 31.0N 85.5W 40 KT 45 MPH...INLAND 120H 17/1800Z 33.5N 85.5W 25 KT 30 MPH...INLAND $$ Forecaster Beven
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Hurricane Linda Forecast Discussion Number 11
2021-08-12 22:36:00| Tropical Depression LIDIA
Issued at 300 PM MDT Thu Aug 12 2021
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Hurricane Linda Forecast Discussion Number 10
2021-08-12 16:50:52| Tropical Depression LIDIA
Issued at 900 AM MDT Thu Aug 12 2021
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linda
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Post-Tropical Cyclone Kevin Forecast Discussion Number 21
2021-08-12 16:31:22| National Hurricane Center (East Pacific)
Issued at 800 AM PDT Thu Aug 12 2021 000 WTPZ41 KNHC 121431 TCDEP1 Post-Tropical Cyclone Kevin Discussion Number 21 NWS National Hurricane Center Miami FL EP112021 800 AM PDT Thu Aug 12 2021 A little bit of convection continues to persist about 200 n mi to the southwest of Kevin's center, but at that distance, it is not considered organized in relation to the cyclone. In fact, Kevin has had this structure for a good 18 hours or so, and it has therefore degenerated into a remnant low. Based on last evening's ASCAT passes, it is assumed that winds as high as 30 kt are still occurring within the circulation. However, the center will be moving over waters colder than 23 degrees Celsius very soon, so a gradual decrease in the winds is expected over the next couple of days. Dissipation of the remnant low in expected in about 3 days. Kevin is moving toward the west-northwest, or 300/12 kt. The remnant low is expected to move along the southwestern periphery of a low- to mid-level ridge centered over the United States and Mexico, which should cause a west-northwestward or northwestward motion until dissipation. There is very little spread in the track guidance, and this last NHC track forecast is just an update of the previous one. This is the last advisory being issued for Kevin. For additional information on the remnant low please see High Seas Forecasts issued by the National Weather Service under AWIPS header NFDHSFEPI and WMO header FZPN02 KWBC. FORECAST POSITIONS AND MAX WINDS INIT 12/1500Z 23.2N 120.6W 30 KT 35 MPH...POST-TROP/REMNT LOW 12H 13/0000Z 24.2N 122.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 24H 13/1200Z 25.5N 124.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 36H 14/0000Z 27.0N 126.9W 20 KT 25 MPH...POST-TROP/REMNT LOW 48H 14/1200Z 28.7N 128.6W 20 KT 25 MPH...POST-TROP/REMNT LOW 60H 15/0000Z 30.2N 129.8W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 15/1200Z...DISSIPATED $$ Forecaster Berg
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