Weather Nerd

A day in the life of hurricane tracking

I’m not back in hurricane-tracking mode here on Weather Nerd — Katia, proto-Lee, and far off hypothetical proto-Maria aren’t really threats just yet — but for those who’d like to do some do-it-yourself storm-watching, I thought I’d make a schedule of a typical day of hurricane forecasting developments, with links to the data sources that update around the listed times.


First, a bit of a glossary, and some background. “NHC” is the National Hurricane Center, and their advisories usually come out a few minutes before the official top-of-the-hour timestamp. (So, for instance, the 5pm advisory comes out around 4:45 or 4:50.) “Full” advisories include the all-important meteorological “discussions” and updated 5-day forecasts. “Intermediate” advisories update the current conditions, but don’t generally add much else, and they’re only issued when watches or warnings are up for some coastline somewhere.

“NAM,” “GFS,” “NOGAPS,” “CMC (Canadian),” “HWRF,” “GFDL” and “ECMWF (European)” are seven of the computer models that NHC looks at, with “runs” either two or four times a day. Loosely speaking, the runs are identified by the time that they start (in “Zulu” or Greenwich Mean Time, e.g., “the 00Z run,” “the 06Z run,” etc.), but they take differing amounts of time to complete. So I’ve listed the approximate times that each model usually spits out new forecast maps for us to look at.

The GFS and ECMWF global models are the most accurate models; NAM, NOGAPS and CMC are the least accurate of these seven. HWRF and GFDL are somewhere in the middle. You can read more here about the various computer models, from Dr. Jeff Masters.

In all cases except HWRF and GFDL, the links below go to the individual, model-specific graphic for the latest “run,” from Ryan Maue’s site. (To check if the model has updated, look at the top middle of the linked image where it says something like “MSLP (hPa) 06Z01SEP2011.” Those first three characters of the timestamp, “06Z” in this example, tell you which model “run” you’re seeing.) For the HWRF and GFDL, whose URLs are storm-specific, my links simply go to Maue’s page; those models at the top of his left-hand column.


Keep in mind that computer models can shift wildly from run to run, and are subject to huge errors, especially in their longer-term forecasts. Do not make any life-or-death decisions based on a computer model forecast! If you’re confused by what the computer models show, you’re probably better off ignoring them, and trusting the NHC. Over an entire season, the official forecast generally outperforms any specific model.

That said, for those of us “weather nerds” who can’t help ourselves, the model maps are like, well, #stormporn. :) So, without further ado, here’s the schedule. All times Eastern Daylight Time. I’ve tried to use font size and weight to give a general idea “how important” each event is.

5:00 AM: Full NHC advisory

5:15 AM: NAM 06z run (simulated radar, satellite)

6:45 AM: GFS 06z run

7:30 AM: HWRF 06z run

7:45 AM: GFDL 06z run

8:00 AM: Intermediate NHC advisory*

11:00 AM: Full NHC advisory

11:15 AM: NAM 12z run (simulated radar, satellite)

12:45 PM: GFS 12z run

1:00 PM: NOGAPS 12z run

1:15 PM: CMC (Canadian) 12z run

1:30 PM: HWRF 12z run

1:45 PM: GFDL 12z run

2:00 PM: Intermediate NHC advisory*

2:45 PM: ECMWF (European) 12z run

5:00 PM: Full NHC advisory

5:15 PM: NAM 18z run (simulated radar, satellite)

6:45 PM: GFS 18z run

7:30 PM: HWRF 18z run

7:45 PM: GFDL 18z run

8:00 PM: Intermediate NHC advisory*

11:00 PM: Full NHC advisory

11:15 PM: NAM 00z run (simulated radar, satellite)

12:45 AM: GFS 00z run

1:00 AM: NOGAPS 00z run


1:15 AM: CMC (Canadian) 00z run

1:30 AM: HWRF 00z run

1:45 AM: GFDL 00z run

2:00 AM: Intermediate NHC advisory*

2:45 AM: ECMWF (European) 00z run

*if watches or warnings are in effect

Of course, reconaissance data is also important, but the recon flights’ schedule varies from day to day, and the data can be a bit difficult to decode. But you’re certainly welcome to try your hand at it here. Unless you’re pretty technically minded, though, it’s probably better to wait for the NHC advisories to explain what the planes found.

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