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  • Writer's pictureTim Donohue

[Thanksgiving 2021] Friday Nov 19 update

We're back to adjust our Friday disruption predictions for the latest weather forecasts. If you haven't done so yet, we'd encourage you to read our first look at Friday: come for the context, stay for commentary on how delays ripple, flight schedules' recovery from COVID and EWR's [magnificently cursed] Runway 11/29. We'll also link to our most recent explainer on the different ways the FAA manages air traffic flows (which often creates delays).

The large-scale weather set-up is unchanged, with a front moving onshore over the Pacific Northwest while another front moves southward over Florida. Light rain has already started at Seattle (SEA) and should become more showery around daybreak, with some clearing expected by midday. Importantly, the transition to a more showery type of rain should suffice in terms of lifting ceilings and visibility. Yesterday we had expressed some concern about a 38 arrival rate in the 9 a.m. hour and resulting demand overage - with the latest forecast in hand, we feel comfortable taking this possibility off the table. That is to say, we expect negligible air traffic delays at SEA tomorrow.

Moving along to San Francisco (SFO), there's some question as to how far south precipitation associated with the Pacific Northwest system pushes. The North Bay figures to get a tenth to quarter of an inch of rain, however rain amounts diminish greatly south of the Golden Gate Bridge (SFO is approximately 15 miles south of the Golden Gate). Nonetheless, a chance for rain exists through much of the morning. We maintain our stance on SFO from yesterday - a 36 arrival rate is the lower bound of our capacity predictions, but with flight schedule recovery lagging there, demand falls underneath 36 in all hours.

Conditions are currently deteriorating in Miami (MIA), as deep tropical moisture streams east into the region. Whereas yesterday it appeared there'd be some meteorological ingredients in place by Friday that might improve conditions, today's outlook is more uncertain. Ultimately, numerous showers and scattered thunderstorms should be expected. We remain unconcerned about air traffic delays resulting from a demand/capacity imbalance, however delays on account of lightning seem increasingly probable (baggage handlers and fuelers are pulled inside halt aircraft turnarounds). Unfortunately, it's more difficult to speculate on the timing of these ramp closures than the timing of demand overages. We should also mention Fort Lauderdale (FLL) will similarly be exposed to delays on account of ramp closures.

Which brings us to Newark (EWR). Unfortunately, the latest wind forecast prompts us to bump up the probability (now 1 in 4) that Runway 29 will be used as the primary arrival runway. The good news is our predicted delays in that scenario remain relatively minor, with the average delay modeled at 9 minutes for arrivals scheduled between 3:30 p.m. and 5:30 p.m. We bet the FAA chooses to manage through this with airborne holding, which would be most acute between 4:30 and 5 p.m. (when delays could reach 20 minutes). If the FAA elects metering or a brief first-tier ground stop, the delays will be disproportionately absorbed by flights originating at nearby airports (we could envision a handful of flights delayed 45 minutes in this case). Winds are forecast to diminish by early evening, which should allow a return to a more optimal 40 arrival rate; if winds don't diminish as forecast, a similar level of delay is predicted for arrivals scheduled in the 7 and 8 p.m. hour.

What does all this mean for travelers? Our guidance remains largely intact, if slightly more favorable. Readers transiting SFO tomorrow should not expect air traffic delays (though delays owing to aircraft servicing, airline staffing, etc. are always lurking). While we had indicated minor delays were possible for SEA in our first look, a refined weather forecast allows us to eliminate air traffic delays from our update predictions. If there's one spot we're slightly more concerned about day-over-day, that would be MIA: no air traffic delays are anticipated, though lightning may intermittently suspend operations. Lastly, late afternoon delays - though very likely minor - in EWR remain possible. If you're scheduled to connect through EWR around 4 p.m. and your layover is planned at underneath an hour, it might be worth at least exploring rebooking options (airlines are increasingly offering flexibility, including no change fee on most tickets). We'd advise all other travelers touching EWR (arriving, departing or with longer layovers) to merely adjust their delay expectations.

Tomorrow, we'll shift our attention to travel on Sunday.

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