NWS SERFC Hydrologic Vulnerability Assessment Monday, March 9 th, 2015 NOAA, National Weather Service Southeast River Forecast Center
Current Weather Map Today s weather map shows a blossoming system in the gulf that will impact the Southeast during this week. A low pressure system is developing over south Texas and will slowly move northeast bring with it moisture and rainfall to most of the Southeast in the coming week. First area of concern is the Tombigbee basin in northeast Mississippi and then on east in what is expected to be a busy week.
Past 30- day departure from normal rainfall Here is the last 30-day departure from normal precipitation graphic. Below normal precipitation is most noted by the area in the red oval. The blue ovals indicate where we have been slightly above normal. The are of most concern currently is the area in Northwest Alabama and Northeast Mississippi. Fortunately there is also some dryness through central Georgia and up the Appalachian chain through North Carolina.
Streamflow in the Southeast is near normal for much of the Southeast. In addition, most of the reservoirs are full or near full pool for this time of year. The area outlined by black shows below normal areas of streamflow. These areas should be able to handle a little more rainfall. However, this is the time of year when normal streamflows are the highest. We are susceptible to flooding over the whole southeast except Central and south Florida as this is their dry season.
Low pressure moving through Southeast Here is the setup for Tuesday Evening. Notice the continued rain chances over the same areas. This is the reason for concern at this moment until the system begins to move east. All areas ahead of the front could receive rainfall. However, the best chances for heavy rainfall will be near and around the front and the low pressure.
SE River Forecast Center 48 hour rainfall forecast Here is the SERFC 48 hour rainfall forecast. A reminder to everyone that this is the precipitation forecast that we include in our models. The river forecasts that we look at include this information. Our base forecast for this comes from the National Weather Prediction Center. The SERFC HAS forecaster then modifies this based on local knowledge and current trends in the radar and issues this for use by the hydrologists.
How much rain is forecast? This is the current 5 day rainfall forecast for the period beginning 8am today through 8am Saturday. Rain will continue all through the week and will be close to the end by Saturday. It will be a wet week for most of the Southeast. Timing and amounts are still something we will be watching very closely so that we can update our forecasts as conditions change.
Ensemble forecasts Here is the Meteorological model Ensemble forecast for the SERFC. You can click on this map to get more detailed information about this map. This has multiple days of forecasts in it and is used for contingency purposes. There is minimal forecaster interaction in these forecasts. These forecasts can help decision makers with contingency planning. For more information, you can go to the below web site for more information and explanations about how these forecasts are produced. http://www.srh.noaa.gov/ serfc/?n=hydrologicensem bles
Summary Here is the status map for the SERFC. Based on our current 48-hour rainfall forecast that is included in our forecasts, we are expecting 21 forecasts to go to flood stage with the current 48 hour rainfall forecast. You can click on the river conditions graphic for updates on the SERFC web site.
SERFC Status SERFC is not on 24-hour operations. Today s morning River Forecasts are available at: http://weather.gov/serfc SERFC will continue to closely monitor for changes in the forecast of location or amounts of heavy rain. The HVA issued today set the stage for the event. The Daily Operational Overview Message will be issued on Tuesday with updated conditions and expectations.
Helpful Bookmarks Monitor the NWS weather radar http://www.srh.noaa.gov/serfc/?n=radar Monitor NWS forecasts: SERFC Hydromet Briefing page http://www.srh.noaa.gov/serfc/?n=testing NWS National 5 day rainfall forecasts http://www.hpc.ncep.noaa.gov/qpf/qpf2.shtml NWS Meteorological Model Ensemble 7 day probabilistic river forecasts http://www.erh.noaa.gov/mmefs/
About this SERFC Briefing These slides are intended for your use. Please feel free to share these with others. If you have any questions please email sr-alr.rivers@noaa.gov, todd.hamill@noaa.gov or contact your local NWS Weather Forecast Office. Remember: SERFC briefings cover freshwater flooding main stem river flooding. For flash flood issues (flooding in less than 6 hours), please monitor your local Weather Forecast office for watches and warnings.