Thursday, Sep. 8 & Friday, Sep. 9 Outlook
Deep tropical moisture streams into the Southeast and eastern Gulf; September schedule peaks early evening demand at LGA
Welcome to any new readers! And as a reminder to long-ish time readers, we’re testing a new format for these outlooks. To both old and new—we’re grateful you’re here.
If you have questions about the content of this outlook, the answers might be in this post (we keep adding to it). Otherwise, let us know if something doesn’t make sense (we welcome feedback of all kinds!).
Thursday, September 8
We forecast TSA will screen 2.313 million travelers (± 0.5σ, or a prediction interval of about 38%, is 2.25-2.38 million travelers), however our Holt-Winters model is still resolving the Labor Day bump. Monday and Tuesday finished in the upper decile of prediction intervals, which was enough to [briefly] turn the trend positive—until that’s digested, we’re inclined to the lower end1 of our predictions (we’d take the under on -0.5σ).
A piece of energy pushes a frontal boundary into Georgia; meanwhile, low pressure drifting northward will funnel moisture into the eastern Gulf and Southeast. Some thunder earlier in the day is possible around ATL, though best chances will be afternoon/evening. While the best moisture looks to be west of MIA, heavy rain is possible along the sea breeze boundary. Out west, the record-shattering heat wave finally begins to dissolve.
We’ll also have to keep an eye on LGA as we transition to September flight schedules: the 6 p.m. hour typically featured 36 scheduled arrivals during August. In September, that looks to be more like 39-40; a material increase, especially with northerly winds (when an arrive-runway-4-depart-13 configuration is favored along with its default rate of 38).
Friday, September 9
We forecast TSA will screen 2.262 million travelers (± 0.5σ, or a prediction interval of about 38%, is 2.20-2.32 million travelers).
A series of cold fronts begin to reach DEN Thursday evening; by Friday evening, the National Blend of Models includes a low chance for thunder (15%), though the forecast discussion leaves out any such mention (instead hinting at a drizzle). If nothing else, the forecast discussion is a reminder that winter is coming—the front range might top out in the 50s and elevations above 9’000 feet could see snow. We’ll be deicing before you know it.
We’re also watching Hurricane Kay even though Los Angeles (LAX) and Phoenix (PHX) are outside the scope of our automation. Heavy rains and gusty winds are forecast throughout Southern California and the Desert Southwest as the center of Kay slides just west of Baja.
While it links to a Google Sheet, it’s an Excel file and relies on the XLOOKUP function, which does not exist in Sheets. You can download the file and open in Excel, which should resolve the #NAME? error; if any readers don’t have Excel, let us know and we can work on a solution.