Atlantic/2019/05L/Archive/30

Although shear seemed to begin to attack Dorian around the time of the last advisory, the storm has made the most of its environmental conditions. The western side of the central dense overcast had been suffering, but deep convection near -80C has continuously been firing in the southwest quadrant of the storm and expanding the CDO back westward, improving the storm's symmetry and thickening the ring of -70C cloud tops around its eye. The eye itself has remained warm and symmetrical. Given the deepening trend of the central pressure of Dorian observed through the last aircraft reconnaissance missions in the storm and the visible improvement in satellite presentation, Dorian's initial intensity has been raised to 150 kt.
The environmental conditions for Dorian are currently very favorable, with light shear out of the southwest. Mid-level moisture continues to rise with relative humidity near 60%, forecast to reach near 70% on day 2. Sea surface temperatures and OHC values are expected to remain very supportive. Wind shear should remain low for the next 36 hours at least, meaning that for this time period the only real prohibitive factor is upwelling that may be induced as the storm slows down over the next few days. By about day 3, the slow motion of the storm, increasing wind shear, and dry air advected from over land will begin to weaken the storm significantly. By day 4, this rate of weakening should increase especially as the chance of landfall increases later in the forecast period.
Dorian continues to track just north of due west. Along this path, in about 6-9 hours, Dorian will likely make landfall on Great Abaco as a category 5 or strong category 4 hurricane. The hurricane should then continue on this track for about the next two days, slowing in forward speed as an approaching trough weakens the mid-level ridge to its north. Around 48h, the storm should begin to track north-northwest into this weakness, although exactly when and how far west this will occur is still uncertain. Model consensus has the hurricane turning north offshore, and while this appears to be the most likely scenario it does not rule out a later Florida landfall or other land effects up the coast. In fact, models are likely forecasting the storm east of where it will end up, given that upper air observations between 06z and 00z in the eastern portion of the United States where the mid-level ridge is have shown that at the 700 hPa level geopotential heights are still rising, indicating that the ridge is still strengthening, contrary to the model belief that the ridge should already be weakening. This has significant implications for how Florida will be affected, as the storm is more likely to track closer to the state's coastline. Regardless of where the storm curves north, once it does, a second upper-level trough will pass to the north, weakening the ridge further and picking Dorian up into the mid-level westerlies, turning and accelerating it toward the northeast, along the Carolina coast.
FORECAST MAX WINDS
INIT 01/0900Z 150 KT 175 MPH
12H 01/1200Z 145 KT 165 MPH
24H 02/0000Z 140 KT 160 MPH
36H 02/1200Z 135 KT 155 MPH
48H 03/0000Z 125 KT 145 MPH
72H 04/0000Z 110 KT 125 MPH
96H 05/0000Z 100 KT 115 MPH