Dangerous Heat in the Western U.S.; Flash Flooding Possible Across Portions of the South

High temperatures in the 90s to 100s and warm overnight temperatures will continue across parts of the Interior Northwest, central California, and the Great Basin. Thunderstorms and heavy rain may produce scattered flash flooding across much of the Southern Rockies into the Southwest, particularly over sensitive burn scars in New Mexico, and across the Southeast into the Carolinas. Read More >

Additional useful information is available on AHPS pages of forecast points. For example, lets look at the Kentucky River at Frankfort. Here is the Additional Information Section:

The first three are USGS links. The first link show how the current 28 day running average streamflow compares to the historical ranges based on the entire 37 year record at Frankfort. In other words, how "normal" the current long-range flow is:

As you can see, the Kentucky River was above normal in December but since that time has fallen to normal levels. You can also see that the river was well above normal through much of the summer. This link also allows the user to change parameters to look at other ranges.

The next link is for a raster hydrograph for the entire length of record at Frankfort. This is a static image:

A raster hydrograph allows one to see the entire history of flow at a location. The floods are small blue blocks while the droughts of long orange bands. Looking at this raster hydrograph one can see the floods at Frankfort usually occur during the winter or early spring and are short lived, while droughts occur during the summer and fall months are are prolonged. It is possible to generate raster hydrographs for other time periods by going to this link and entering the USGS station number for a location.

The next link goes to the USGS inundation mapper for the entire country. These maps are similar to the inundation maps available at the Inundation Mapping link at the top of the AHPS page.

The next two links show the range of river forecasts given an ensemble of precipitation and snow melt forecasts. The first link is for the 1 to 3 day range, the second for the 3 to 7 day range.

Notice, since there is little rainfall expected until February, the range of river forecasts is narrow. Also at this link are the precpitaton, snow water content, and temperature ranges used to make the forecast.

The last link shows the probablities of how low the Kentucky River could fall during the next 90 days. It shows both the normal (historical) probabilities and the (conditional) probablities based of the current long-range temperature and precpitation outlooks.

You can see that there is an 80% chance that the Kentucky River at Frankfort will fall below 8 feet with in the next 90 days. Normally, this probability is around 93% at this time of year. This chart is most useful during prolonged droughts.