Less Humid Days; Watching Hurricane Dorian

DRIER AIR SETTLING IN: For our Thursday, the sky is sunny with temperatures reaching for those upper 80s and lower 90s by this afternoon. Our dewpoints are lower, making for lower humidity levels the next couple of days. We we are in store for a couple of delightful nights ahead as clear conditions means 60s are in the forecast for South/Central Alabama. Expect those pleasant temps tomorrow and Saturday morning. For the daytime forecast tomorrow, expect ample sunshine and continued lower humidity with highs ranging from the lower to mid 90s across the area.

FOOTBALL WEATHER: Alabama will take on Duke in the Chick Fil A Kickoff Classic in Atlanta (2:30p CT kickoff)… the game will be played indoors (Mercedes Benz Stadium), but outside the sky will be mostly sunny. Temperatures will peak close to 90 in Atlanta Saturday afternoon.

Auburn travels to Dallas/Fort Worth to take Oregon at AT&T Stadium Saturday evening (6:30p CT kickoff). Temperatures will top out in the mid 90s during the day Saturday with a sunny sky, falling though the 80s during the game.

LABOR DAY WEEKEND: Saturday will be a mainly sunny day and highs through Monday will be in the lower 90s. Moisture levels will rise a bit Sunday and Monday, and we will mention widely scattered showers both days, but nothing widespread and the sky will be partly sunny for the most part.

HURRICANE DORIAN: At 500 AM AST, the center of Hurricane Dorian was located near latitude 20.5 North, longitude 66.6 West. Dorian is moving toward the northwest near 13 mph, and this general motion is expected to continue through Friday. A west-northwestward motion is forecast to begin Friday night and continue into the weekend. On this track, Dorian should move over the Atlantic well east of the southeastern and central Bahamas today and on Friday, and approach the northwestern Bahamas on Saturday. Maximum sustained winds are near 85 mph with higher gusts. Strengthening is forecast during the next few days, and Dorian is expected to become a major hurricane on Friday. The minimum central pressure based on earlier Air Force Reserve Hurricane Hunter data is 991 mb (29.27 inches).

Dorian continues northwestward and confidence in the track forecast is fairly high for the first 48 hours, with Dorian expected to continue moving northwestward and then begin to turn west-northwestward between mid-level ridging to the north and a mid to upper-level low retrograding westward across the Straits of Florida. The models, and their ensembles, continue to diverge after 48 hours and have not really budged from their respective solutions compared to yesterday. The GFS is a northern outlier from the rest of the guidance, showing a weaker ridge and bringing Dorian close to the Florida/Georgia border, while the UKMET and ECMWF models show stronger ridges and remain the southernmost solutions near South Florida. Given the spread in the guidance, the new NHC forecast blends the previous forecast with the simple multi-model consensus aids and the HCCA and Florida State Superensemble aids, and it actually ends up in a position very close to the tightly clustered global model ensemble means. The most notable change in the new forecast is that it’s a little bit slower than the previous one as Dorian approaches Florida.

Various shear analyses are indicating 10-15 kt of southwesterly shear over Dorian at the moment, but the global models show this shear diminishing within 12-24 hours. With lower shear and very warm waters, all of the intensity models forecast Dorian to begin strengthening again soon, and rapid intensification could occur. The updated NHC intensity forecast has been increased from the previous one and most closely follows the HCCA and Florida State Superensemble aids during the first day or two. After 48 hours, the official forecast is near or just above the intensity consensus, but it’s still lower than the solutions shown by the HCCA, Florida State Superensemble, and the HWRF. Dorian is likely to reach major hurricane strength in the next day or two and is forecast to maintain that status until it reaches land.

Key Messages:

1. The risk of dangerous storm surge and hurricane-force winds later this week and this weekend continues to increase in the central and northwestern Bahamas and along the Florida east coast, although it is too soon to determine where these hazards will occur. Residents in these areas should ensure they have their hurricane plan in place and not focus on the exact forecast track of Dorian’s center.

2. Heavy rains are expected to occur over portions of the Bahamas, Florida, and elsewhere in the southeastern United States later this

Model consistency gives us growing confidence that Dorian will recurve into the mid-latitude westerlies east of Alabama, keeping our state on the “dry side” of the system. For now we expect little impact in Alabama, with the storm staying east of us, but we know things can certainly change this far out. There will be little, if any direct impact, along the Gulf Coast over the Labor Day weekend (places like Gulf Shores, Destin, and Panama City Beach. A few showers and storms are possible there, mainly Sunday and Monday, but it is the typical late summer activity.

ERIN: This is the last advisory on Erin from the National Hurricane Center. At 500 AM EDT, the center of Post-Tropical Cyclone Erin was located near latitude 36.1 North, longitude 71.6 West. The post-tropical cyclone is moving toward the north-northeast near 15 mph. A turn toward the northeast and a faster forward motion are expected later today, with this motion continuing through Friday. Maximum sustained winds are near 35 mph with higher gusts. The post-tropical cyclone is expected to strengthen a little on Friday before it is absorbed by a larger extratropical low over eastern Canada Friday night. The estimated minimum central pressure is 1005 mb (29.68 inches).

NEXT WEEK: The first week of September looks pretty routine with partly to mostly sunny days and highs in the lower 90s, which is pretty close to average for the early September. There will remain the chance for a few afternoon showers and storms, but these will be few and far between.

Have a great day!
Ryan