Atlantic/2019/05L/Archive/31

A storm with the persistence and intensity of Dorian's caliber is a rare sight in the Atlantic basin. Visible satellite imagery from this morning shows an exceptionally smooth and well-defined central dense overcast around a highly stable and symmetric eye. The ring of -70C convection discussed in the previous advisory has not changed much in the last few hours and remains stout on infrared satellite data. Radar imagery from the Bahamas, Miami, recon, and spaceborne microwave data from SSMIS at 1019z all suggest that Dorian's core is in a stable configuration and without clear signs of an ongoing or imminent eyewall replacement cycle, though banding is supportive of one commencing in the evening or later. An Air Force Reserve reconnaissance aircraft and an NOAA P-3 Orion investigating the storm sampled flight-level winds of 159 kt and an unflagged SFMR surface wind of 170 kt, with possible higher values flagged as having questionable accuracy. The eyewall has also been found to be remarkably uniform in its distribution of winds. Based on this data, Dorian's current intensity suggests raising the current intensity further to a 155 kt Category 5 hurricane. The central pressure has also fallen significantly during this time, and a substantial increase in lightning in the eyewall over the last few hours has been noted on GOES-16 GLM imagery.
As we have long anticipated, the Bahamas has been a pristine incubator for tropical cyclone development, with all classical intensification parameters "in the green", so to speak. Wind shear, oceanic heat content, and deep-layer moisture should remain supportive of Dorian's intensity for at least the next 36 hours as Dorian slowly reaches the Gulf Stream. Afterwards, a forecast slow-down or quasi-stationary stall could result in upwelling, with the ocean-coupled HWRF and HMON models showing sea temperatures falling below 25C during this critical juncture. This is likely sufficient to bring down the intensity some, perhaps significantly if Dorian stalls longer than anticipated. Once Dorian gets moving again, it may be difficult for the storm to recover substantially from upwelling as we've seen with storms historically. This, combined with late term environmental decreases in sea temperatures,increases in wind shear, as well as possible land interaction, should result in progressive weakening as Dorian gains latitude.
Uncertainty remains over the track of Dorian, whose future impacts remain predicated on highly precise timing of several features and storm-environment interactions. It is a virtual certainty that the northern Bahamas, especially Great Abaco, will suffer catastrophic and long-lasting impacts from their most powerful storm in recorded history. Hurricane conditions are expected to affect these islands for at least a day. Dorian is currently moving slightly north of due west under the influence of the deep-layer subtropical ridge to the northeast. A shortwave trough over the Ozarks is expected to weaken the ridge some and promote a weakness over the Eastern Seaboard, slowly coaxing Dorian towards the north in approximately 36-48 hours before a second shortwave reinforces this weakness and allows Dorian to track with more rapidity towards the north and north-northeast. The latest model track guidance is tightly clustered in a track that parallels near but not over the Southeastern United States coast, resulting in a consensus track scraping the Outer Banks. Still, due to the intensity of the system and the sensitivity of the storm's track to minor perturbations during the weak steering field produced in two days, all interests along the coast are strongly advised to continue monitoring the system. As discussed in the previous advisory, the currently modeled ridge may be underforecast, which could result in a track farther west.
FORECAST MAX WINDS
INIT 01/1500Z 155 KT 180 MPH
12H 02/0000Z 155 KT 180 MPH
24H 02/1200Z 145 KT 165 MPH
36H 03/0000Z 130 KT 150 MPH
48H 03/1200Z 120 KT 140 MPH
72H 04/1200Z 105 KT 120 MPH
96H 05/1200Z 100 KT 115 MPH