000 WTNT45 KNHC 070842 TCDAT5 Hurricane Danielle Discussion Number 25 NWS National Hurricane Center Miami FL AL052022 900 AM GMT Wed Sep 07 2022 Danielle's cloud pattern has significantly improved over the past 6 hours. The banding eye feature has warmed back up and cleared out, and the cloud tops are cooling in two prominent curved bands located in the north and south semicircles. The subjective Dvorak T-numbers from TAFB and SAB have increased, and a UW-CIMSS OPEN-AIIR satellite intensity analysis yields 70-75 kt. These data and the earlier SAROPS surface wind retrieval support raising the initial intensity to 70 kt for this advisory. Danielle should continue moving over marginally warm waters for just a few more hours, so some fluctuations in strength, similar to what the cyclone has just undergone, are still possible. Satellite imagery and global model data indicate that a favorable position of a polar jet finger associated with the approaching baroclinic zone may be dynamically influencing Danielle's short-term intensification. By early Thursday, the cyclone is expected to traverse a sharp sea surface temperature gradient of 20C or less. These cooler waters, along with the eventual loss of dynamic forcing should cause a gradual weakening trend through the early next week. Danielle's initial motion is estimated to be northeastward, or 050/12 kt. Once again, there is no significant change to the NHC forecast philosophy. The hurricane should continue accelerating in response to a vigorous baroclinic system approaching from the northwest midway between Newfoundland and Danielle. Danielle is forecast to interact and merge with the system mentioned above late Thursday night into Friday. Over the weekend, the large post-tropical storm-force low is expected to slip south back into the deep-layer mid-latitude westerlies, turn south-southeastward to southeastward, and continue in this general heading through early next week. The NHC forecast is similar to the previous one and is close to the various multi-model consensus aids. Danielle is producing a vast area of very rough seas over the central-north Atlantic. More information can be found in the High Seas Forecasts issued by the Ocean Prediction Center under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php. The UK Met Office also has information in High Seas Forecasts for the west Central and east Central sections issued under WMO header FQNT21 EGRR and on the web at metoffice.gov.uk/weather/specialist-forecasts/coast-and-sea/high- seas-forecast FORECAST POSITIONS AND MAX WINDS INIT 07/0900Z 43.4N 38.1W 70 KT 80 MPH 12H 07/1800Z 44.4N 35.9W 70 KT 80 MPH 24H 08/0600Z 46.3N 33.4W 65 KT 75 MPH 36H 08/1800Z 48.6N 32.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 09/0600Z 50.5N 32.7W 55 KT 65 MPH...POST-TROP/EXTRATROP 60H 09/1800Z 50.0N 34.7W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 10/0600Z 48.6N 33.9W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 11/0600Z 43.9N 23.8W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 12/0600Z 42.2N 15.1W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Roberts