This is probably the best way to describe my relationship with Hurricane Dorian. The now-Category 2 Hurricane is drifting toward Florida. Gaining some strength. Gaining a little predictability.
Total transparency here: For the first few days, this thing was about as unpredictable a storm as I’ve attempted to forecast during my five years in Hattiesburg. And that’s not to say I’ve done a great job in the past. I’m certain previous forecasts had flaws.
But this one is quite the pain in the neck.
From the NHC
SUMMARY OF 1100 PM AST…0300 UTC…INFORMATION
———————————————–
LOCATION…23.3N 68.4W
ABOUT 295 MI…470 KM ENE OF THE SOUTHEASTERN BAHAMAS
ABOUT 580 MI…930 KM E OF THE NORTHWESTERN BAHAMAS
MAXIMUM SUSTAINED WINDS…105 MPH…165 KM/H
PRESENT MOVEMENT…NW OR 325 DEGREES AT 12 MPH…19 KM/H
MINIMUM CENTRAL PRESSURE…977 MB…28.85 INCHES
The NOAA and Air Force Reserve Hurricane Hunter aircraft have been tag-teaming the reconaissance of Dorian tonight, providing useful information about what has changed during the past several hours. They found the pressure has dropped to about 977 mb, with recent SFMR data of about 90 kt (also supported by flight-level winds). These data are also consistent with satellite imagery that show Dorian with a larger, deeper central dense overcast than this afternoon. Thus the wind speed is raised to 90 kt on this advisory.
The initial motion is about the same as before, 325/10 kt. Dorian is expected to gradually turn to the west-northwest on Saturday, and westward on Sunday due to a building ridge over the southwestern Atlantic. While the model guidance generally shows this scenario in a broad sense, there are substantial timing differences among the guidance. The source of the uncertainty can be attributed to challenges in forecasting the strength and orientation of the mid-level ridge over the southeastern United States in a few days, along with exactly where and how large Dorian is by then. As you can imagine, with so many complex variables in play, it is no wonder the models have been having a difficult time nailing down the path of the hurricane. There’s been a notable trend on this model cycle toward a slower, more westward track beyond 36 hours, which can be seen most strongly in the GFS-based guidance. The track forecast is shifted southward beyond 36 hours, and is about 30 n mi south of the previous one at 96 h. We will see if this southward trend in the models continues after the dropsonde data collected by the G-IV gets incorporated into the 00Z models. Users are reminded to not focus on the exact forecast track, as typical forecast errors at days 4 and 5 are around 155 and 205 miles, respectively.
There is still substantial middle- and upper-level dry air on the south side of the hurricane, as shown by tonight’s G-IV mission, which has been allowing only slow strengthening during the day. As Dorian turns west-northwestward, however, shear should drop somewhat due to it moving on the northeast side of an upper-level low near the Florida Straits, and the winds aloft will no longer be pointed toward the core, which will help decrease dry air entrainment. All these changes should promote intensification while Dorian moves over the 29C waters east of Florida, so the intensity forecast is raised from the previous one, consistent with the corrected-consensus guidance. Unfortunately, I don’t see any large-scale factors that would prevent Dorian from becoming an extremely dangerous category 4 hurricane during the next few days.
Quick bite of model data
The modeling isn’t doing much better overnight, but it does look like the next 72 hours are starting to come together
Beyond 72 hours, though, there is a lot of discrepancy. Things fan out quite a bit. Notice though, that fewer and fewer models take Dorian into the Gulf of Mexico.
The Gulf isn’t completely out of play, so to speak, but it looks less likely that Dorian will make it to the Gulf.
That said, as always, never say never.
The intensity guidance shows a pretty consistent trend of maintaining current strength or gaining strength during the next 72 hours.
What parts of the forecast that are a total lock?
None. This forecast is likely to change. Sadly, with tropical systems nothing is ever truly ‘locked in’ which is why we always encourage you to follow the forecast with these systems closely. It is also why we try our best to kick out new forecasts as much as possible.
The Bottom Line
Right now – unless you are reading this from the Caribbean – we are in a wait-and-see position. Circling the airport, so to speak. For Gulf Coast folks, as I mentioned last night on the 10p news, we may have to wait until Thursday evening before we get a better idea about what it means for the Louisiana, Mississippi and Alabama region.
So for now, check your Hurricane Preparedness Kit, check your supplies, make sure you have a plan. Double-check your insurance coverage, make sure you don’t have trees with loose branches or dead limbs around or near the house, and check nearby storm drains. But outside of that, just hang tight!
