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HAS/HPC Forecast
Information
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Forecasting anything is not a clairvoyant science. Forecasting precipitation is no exception. When we forecast future precipitation, the amounts we expect are attentuated and broadened to account for our uncertainty.
For example, if we anticipate that a large portion of Middle Tennessee will get an inch of rainfall (on average), in most cases it is a realistic expectation (especially in thunderstorm events) that some scattered places within this region will get at least two inches while other places nearby get very little. Because we cannot
pinpoint specifically which small areas will get two inches and which will get very little, we 'smooth-out' the precip forecast to exhibit essentially an average over the area (areal average). This compensates for our uncertainty.
Latest
48-hr HAS QPF Image (This image can be seen in more
detail by clicking on the image or its label.) It shows the
most recent 48-hr total Quantitative Precipitation Forecast (QPF)
generated by the HAS Unit at the RFC. The QPF amounts shown
here were used as input to NWS Hydrologic River Models. Typically,
a HAS QPF is generated in the morning and evening 7 days a week.
The forecast is generated by hand for four 6-hr periods. These
individual periods can be viewed by clicking on the links below.
Generally, they are available about a half-hour after the QPF has
been saved by the HAS forecaster. A SHEF-encoded
text product of the HAS QPF is also produced. |
Latest
48-hr HPC QPF Image (This image can be seen in more
detail by clicking on the image or its label.) It shows the
most recent 48-hr total QPF generated by the Hydrologic Prediction
Center. This image is generated from national QPF guidance
provided by the Hydrologic Prediction Center. (See below.) |
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Latest
montage of various models' QPF The following is a montage of various model forecasts, shown for comparison only. Only the map marked (Fcst) is the official QPF used in our river model. |
Extended QPF (irregular basis)
The following graphics, if any are visible, are created only during events when
certain criteria are met. In certain situations, the OHRFC produces 60- or 72-hour Quantitative Precipitation Forecasts. If such
a forecast was issued within the past 24 hours, you can view it from the links below. Otherwise, no links are shown. Please note, however, that only the cumulative total is shown for a forecast; no intermediate totals. For example, if we produce a 72-hr forecast, the 60-hr forecast shown on this page will show another forecast from a different forecast cycle, not a partial total of the 72-hr forecast. |
Latest
60-hr HAS QPF Image (This image can be seen in more
detail by clicking on the image or its label.) It shows the
most recent 60-hr total Quantitative Precipitation Forecast (QPF)
generated by the HAS Unit at the RFC. The QPF amounts shown
here were used as input to NWS Hydrologic River Models. Typically,
a HAS QPF is generated in the morning and evening 7 days a week.
The forecast is generated by hand for four 6-hr periods. These
individual periods can be viewed by clicking on the links below.
Generally, they are available about a half-hour after the QPF has
been saved by the HAS forecaster. A SHEF-encoded
text product of the HAS QPF is also produced. |
Latest
60-hr HPC QPF Image (This image can be seen in more
detail by clicking on the image or its label.) It shows the
most recent 60-hr total QPF generated by the Hydrologic Prediction
Center. This image is generated from national QPF guidance
provided by the Hydrologic Prediction Center. (See below.) |
Latest
72-hr HAS QPF Image (This image can be seen in more
detail by clicking on the image or its label.) It shows the
most recent 72-hr total Quantitative Precipitation Forecast (QPF)
generated by the HAS Unit at the RFC. The QPF amounts shown
here were used as input to NWS Hydrologic River Models. Typically,
a HAS QPF is generated in the morning and evening 7 days a week.
The forecast is generated by hand for four 6-hr periods. These
individual periods can be viewed by clicking on the links below.
Generally, they are available about a half-hour after the QPF has
been saved by the HAS forecaster. A SHEF-encoded
text product of the HAS QPF is also produced. |
Latest
72-hr HPC QPF Image (This image can be seen in more
detail by clicking on the image or its label.) It shows the
most recent 72-hr total QPF generated by the Hydrologic Prediction
Center. This image is generated from national QPF guidance
provided by the Hydrologic Prediction Center. (See below.) |
NCEP HPC QPF Guidance Products
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