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| #932249 (Received by flhurricane at: 5:05 AM 10.Jul.2018) TCDAT3 Tropical Storm Chris Discussion Number 15 NWS National Hurricane Center Miami FL AL032018 500 AM EDT Tue Jul 10 2018 The satellite presentation of Chris has improved overnight with an increase in convective banding and the recent development of a banding eye. An earlier NOAA and an overnight Air Force Reserve aircraft have noted the presence of a ragged 25 n mi wide eye, which can also be seen in NWS WSR-88D radar imagery from Morehead City, North Carolina. Despite the increase in organization the Air Force aircraft did not find winds to support hurricane strength. In fact, the plane only measured peak 850 mb flight level winds of 66 kt and SFMR winds of around 50 kt. However, there is likely some undersampling as the plane only made one pass through each quadrant. Therefore the initial remains 60 kt, which is compromise between the most recent satellite estimates and the lower reconnaissance data. The aircraft did report that the pressure has fallen to 993 mb. Recent satellite and aircraft fixes suggest that Chris may be beginning its much anticipated northeastward motion, albeit very slow at the moment. A large mid-latitude trough is forecast to drop southeastward over eastern Canada and the northeastern United States which should begin to steer Chris on a faster northeastward heading over the next day or so. As the trough deepens, Chris should accelerate further as it becomes embedded within deep-layer southwesterly flow ahead of the trough. Chris is forecast to pass well southeast of Nova Scotia in a couple of days, then move near or over southeastern Newfoundland in about 72 hours. The track guidance remains in good agreement on this scenario, but some speed differences remain. The updated NHC track forecast is similar to the previous advisory and lies between the slower ECMWF and the various consensus aids. As Chris begins to move northeastward, it will be leaving the area of upwelled cooler waters and traversing warm SSTs during the next 24 to 36 h. This should result in strengthening and Chris is expected to become a hurricane later today. By 48 h, Chris will be moving over colder waters north of the Gulf Stream and begin interacting with a frontal system. Extratropical transition is expected to be complete in about 60-72 h, and the extratropical low is forecast to gradually weaken after passing Newfoundland. The new NHC intensity forecast is closest to the Florida State Superensemble, which is a little higher than the statistical guidance. FORECAST POSITIONS AND MAX WINDS INIT 10/0900Z 32.6N 73.9W 60 KT 70 MPH 12H 10/1800Z 33.1N 73.2W 70 KT 80 MPH 24H 11/0600Z 34.4N 71.4W 75 KT 85 MPH 36H 11/1800Z 36.5N 68.2W 80 KT 90 MPH 48H 12/0600Z 39.7N 64.0W 75 KT 85 MPH 72H 13/0600Z 46.5N 53.3W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 14/0600Z 50.7N 38.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 15/0600Z 53.0N 23.0W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown |