This is a repost of an email inquiry:
GFS 0-240h.
is not correct 6 hrs Accumulated Precipitation.
Correct is 3 hrs (on metgram is 3 hrs Accumulated Precipitation ).
Am I wrong?
GFS 0-240h is not correct 6 hrs Accumulated Precipitation. Correct is 3 hrs (on diagram)
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sonny.zinn
- Posts: 361
- Joined: May 8th, 2019, 1:31 pm
- Registered HYSPLIT User: Yes
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sonny.zinn
- Posts: 361
- Joined: May 8th, 2019, 1:31 pm
- Registered HYSPLIT User: Yes
Re: GFS 0-240h is not correct 6 hrs Accumulated Precipitation. Correct is 3 hrs (on diagram)
Thank you for contacting us about accumulated precipitations. One of our scientists looked into the issue you raised and concluded there is no error. Here is the explanation:
There is no inconsistency. The GFS 1-degree forecast file used here is at 3-hour intervals and the precipitation is a 6 hour accumulation.
For example, for a 00z forecast file, the 1st time period after the forecast start is 03z. At that time the precipitation accumulation has only been over 3-hours (00-03z), but it is still called a 6-hour accumulation. At the next time period, 06z, the accumulation period is 6-hours (00-06z) and this ends the accumulation. At the next time period, 09z, the accumulation is over 3-hours (06-09z). The next time period, 12z it is over 6-hours (06-12z), and so on.
The program that displays the precipitation amounts in 3-hour intervals on the meteorogram does the subtraction to calculate 3-h accumulations for the entire forecast period. Using the above example, at the valid time of 06z, what is displayed on the plot is the precipitation value at 06z minus the value at 03z.
There is no inconsistency. The GFS 1-degree forecast file used here is at 3-hour intervals and the precipitation is a 6 hour accumulation.
For example, for a 00z forecast file, the 1st time period after the forecast start is 03z. At that time the precipitation accumulation has only been over 3-hours (00-03z), but it is still called a 6-hour accumulation. At the next time period, 06z, the accumulation period is 6-hours (00-06z) and this ends the accumulation. At the next time period, 09z, the accumulation is over 3-hours (06-09z). The next time period, 12z it is over 6-hours (06-12z), and so on.
The program that displays the precipitation amounts in 3-hour intervals on the meteorogram does the subtraction to calculate 3-h accumulations for the entire forecast period. Using the above example, at the valid time of 06z, what is displayed on the plot is the precipitation value at 06z minus the value at 03z.