Edited Version of March 25, 1999 Transcript
FLOOD FORECASTING, TODAY AND TOMORROW

Featuring

Wendy Pearson, Service Hydrologist
Grand Forks Weather Service Office

Dean Braatz, Hydrologist-In-Charge
North Central River Forecast Center

Dr. John Ingram, Program Director
Advanced Hydrologic Prediction System

with

Noreen Schwein, Applications Hydrologist
Central Region Headquarters

Amy Sebring, Moderator

[This transcript has been reformatted for readability. The original text may be found online.]

Amy Sebring: Welcome to the Red River room of the EIIP Virtual Forum!

Today we have the privilege of presenting some distinguished visitors from the National Weather Service to speak about Flood Forecasting: Today and Tomorrow; but first some quick instructions.

When you see a blue Web address, you can click on it and the referenced Web page should appear in a browser window. After the first one, the browser window may not automatically come to the top, so you may need to bring it forward by clicking on a button at the status bar at the bottom of your screen. Be careful not to minimize or resize the browser window that has the Red River page in it, or it may cut you off. Please do not use Direct Messaging to our guests or the Moderator, because it makes it more difficult to follow the discussion.

You will have an opportunity to ask questions during this session, afterwards in open discussion, and if we still don't get to it, we will follow up via email. If your system or ISP has an inactivity timeout, you may want to keep your connection alive by sending a Direct Message, such as a "hello" to one of the other members here!

See http://www.emforum.org/redriver/workshop/wk990325.htm for background information on today’s session; there are links at the bottom of that page to some of the information we will be discussing today.

We have a great deal of information to cover, so there is also an approximate agenda we will try to follow for the layout of the session at http://www.emforum.org/redriver/workshop/ag990325.htm .

Right before we begin the first Q&A portion I will review how to submit questions or comments.

I would like to mention that we did try to include the Canadian side of the border today, but they regretted that they were unable to participate. They did tell me that their revised Flood Outlook will be coming out very soon, and when it is issued, you will be able to access from http://www.gov.mb.ca/natres/watres/wrb_main.html .

Now it is my pleasure to introduce our participants for today. I am sure many of you already know Wendy Pearson, Service Hydrologist from the Grand Forks Weather Forecast Office.

We are also pleased to welcome Dean Braatz, Hydrologist-In-Charge at the North Central River Forecast Center in Chanhassen, Minnesota.

Joining us from Silver Spring, Maryland, is Dr. John Ingram, Program Director for the Advanced Hydrologic Prediction System.

Also on hand to assist with answering questions is Noreen Schwein, Applications and Development Hydrologist from the NWS Central Region HQ in Kansas City, Missouri.

Welcome to you all, and thank you for taking the time to be with us today. Wendy, if you will please start us off.

Wendy Pearson: I will start off with some basin information about our NWS Products. Here are the factors that determine snowmelt flood potential. Factors that determine the degree of snowmelt flooding are: Fall soil moisture, snowcover, water equivalent in snowcover, depth of frost, early or late Spring thaw, occurrence of thaw and heavy precipitation and ice jams.

Here are the current conditions for the 1999 spring season: Fall soil moisture was above normal. Winter season precipitation was above normal through January. February precipitation was below normal, and March precipitation has been near normal to date.

Snowcover is 0-12 inches. Water equivalent in that snowcover ranges from 0-4 inches. Frost depth has started to decrease. River ice has started to break up in most channels. This Spring's melt season has been ideal. However, we may have precipitation in the forecast for next week.

Snowmelt Outlooks are to be used as a long range planning tool. The Outlook assumes normal meteorological conditions during the snowmelt. Since weather predictions are only accurate to five days, abnormal weather, even for a brief period, can have a significant effect on river levels. Therefore, actual crests may exceed or fall short of the guidance levels indicated in the Flood Outlooks.

Daily River Forecasts will be provided for river forecast points that experience river levels at or above flood stage. These river forecasts are based on short range weather predictions and are updated as conditions become known. The National Weather Service Forecast Office in Eastern North Dakota's Webpage is http://www.crh.noaa.gov/fgf/ . I will turn the presentation over to Dean Braatz at the RFC now.

Dean Braatz: Hydrologic forecasts are issued when flooding is expected or in progress for river stations that have been designated as regular flood forecast points. Forecasts are issued daily for mainstem rivers and selected tributary points, while forecasts for most tributary points are prepared when the stage reaches flood stage levels or higher.

Dean Braatz: Forecasts are issued routinely during the morning and evening and at other times as the need arises. The RFC hydrologic forecast product is provided as a five-day, six-hour time step time series. The highest stage value in the time series is assumed to approximate the crest forecast, unless the hydrograph has a very sharp response such that the crest may occur between two six-hour time intervals.

Current model states (soil moisture, snow water equivalent, river flows, reservoir levels) from the operational hydrologic model are used as the starting conditions for outlook runs. Hence, one day of QPF and five days of forecast temperatures are used. (QPF is the Quantitative Precipitation Forecast, which is a 24 hour precipitation forecast.) Normal precipitation from the date of the outlook and normal temperature melt patterns for the extended period, until melt is complete, are also included.

Collection of satellite, airborne, and ground data, including measurements of snow depth, snow water equivalent, frost depth, ice conditions, precipitation, temperature, stage, and flow data is required to provide data input for hydrologic models. The information also provides facts for model output evaluation, in the process to prepare outlooks and forecasts. Longer-term needs for the data supports model development, model calibration, and related operational procedures.

The RFC coordinates with the weather offices and other agencies. Since the 1997 Flood, the ratings have been adjusted for the new floods of record. Calibration of the new runoff model is underway.

Amy Sebring: Thank you Dean. We will now take about 10 minutes for questions/comments from the "floor". Audience please send in just a question mark (?) to indicate you wish to be recognized, go ahead and compose your comment or question, but wait for recognition before hitting the enter key or clicking on Send. Please indicate to whom your question is addressed. We are ready for your questions or comments.

Question:
Amy Sebring: I have one to start with if I may --- Dean, I have been looking for your forecasts on the Web. Are they available?

Dean Braatz: The forecasts are on the Grand Forks Weather Office Homepage.

Question:
Pete Jensen: Has your E-19 data been adjusted to account for the home buyouts we (FEMA) did after the 97 floods?

Amy Sebring: Pete can you explain E-19 for those of us who might not know?

Pete Jensen: I believe it is the data set that is used by NWS to describe the effect of a given flood level.

Wendy Pearson: Cross section data that you are probably referring to is not usually included in the E-19 per se. We have updated all E-19s in the Red River Valley after the 1997 flood for the info they are to contain. The new cross sections that will be in place when the permanent dike alignment is built will be developed by the US Army Corps of Engineers and that data will be coordinated to the NWS.

Question:
Amy Sebring: Wendy or Dean, you are about to issue a revised Flood Outlook tomorrow? Can you give us a heads up or do we need to wait?

Wendy Pearson: We will be updating flood potential information tomorrow.

Question:
Lisa Bourget: When will that information be available on the web?

Wendy Pearson: The updated flood potential information will be available tomorrow afternoon at the latest; however, we are issuing daily flood forecasts for specific sites on a daily basis. Those flood statements are already on our homepage.

Question:
Amy Sebring: Can you summarize where you anticipate some problems this year?

Wendy Pearson: We are looking at moderate flooding conditions being possible in the north portion of the Red River from Halstad to the Canadian border and we will be monitoring the Sheyenne and Red Lake river basins closely for their contribution to the Red.

Amy Sebring: Let's continue; we are doing pretty well with our schedule. Next to give us an introduction to the Advanced Hydrologic Prediction System, the "tomorrow" part of our program is Dr. John Ingram. John please.

John Ingram: The Advanced Hydrologic Prediction System may be referred to as AHPS. Within AHPS, we're coupling National Weather Service (NWS) weather and climate forecasts with hydrologic numerical models to provide a suite of hydrologic forecast products from days to months into the future. AHPS is a National program initiative appearing within the President's FY2000 Budget Request to Congress.

During FY 2000, the National implementation of AHPS will begin in the Upper Midwest (which includes Wisconsin, Minnesota, Michigan, Illinois, and portions of Iowa, Missouri, and North Dakota) and tributaries within the upper Ohio River basin (which includes Kentucky, West Virginia, Ohio, and western Pennsylvania).

AHPS will provide new forecasts containing more information on river levels and river flow volumes. See this slide for further information on what AHPS will provide.

http://tgsv5.nws.noaa.gov/oh/ahps/slide5.htm

Because AHPS provides more information, it moves people from a "reactive scenario" to a more "proactive scenario."

http://tgsv5.nws.noaa.gov/oh/ahps/slide6.htm

More information on AHPS may be found at: http://www.nws.noaa.gov/oh/ahps/

I will now share some information about AHPS probabilistic products. In addition to existing hydrologic forecast information, AHPS provides extended lead-time forecasts which account for precipitation and climate predictions. For example:

http://tgsv5.nws.noaa.gov/oh/ahps/slide12.htm

AHPS enables the display of a river forecast which includes precipitation and climate predictions.

This slide shows a flood-forecast map and example AHPS product.

http://tgsv5.nws.noaa.gov/oh/ahps/slide16.htm

Now I wish to share some information regarding the one location AHPS has been implemented. The NWS has been running AHPS for the Des Moines River Basin, Iowa since March of 1997. Following the Great Flood of 1993 in the Midwest, the Des Moines basin was chosen as a first phase toward a national implementation of AHPS.

User response for the Des Moines AHPS has been positive. An open house is scheduled for the Des Moines Weather Forecast office this next week on Wednesday afternoon, 31 March. During that time, modernized technologies of the NWS will be presented, including AHPS.

Further information regarding AHPS may be obtain at: AHPS@noaa.gov

Benefits of AHPS follow: Longer-range forecasts resulting from AHPS advanced modeling will help ecosystem managers, farmers, emergency managers, and many other water users prepare for the impact of events ranging from droughts to floods.

National implementation of AHPS will save lives and at least $200 million per year in flood losses and an additional $400 million per year in economic benefits to water resource users.

Amy Sebring: Again, links to more information about the AHPS system are provided at the bottom of the workshop background page for your future reference. Dean, do you have anything you would like to add regarding the AHPS system?

Dean Braatz: There are monthly suites of AHPS products that are issued each month that can be found on the Des Moines Forecast Office Homepage.

Wendy Pearson: That URL should be http://www.crh.noaa.gov/dmx/ . The URL provided is for the Des Moines office homepage and you need to click on Water to access the AHPS products.

Amy Sebring: Thank you Dean. We are now ready for questions/comments regarding AHPS. Remember to send in a question mark (?) please.

Question:
Amy Sebring: John, I am not clear on how the probabilities are calculated. Can you clarify? Are they based on the precipitation probabilities? As opposed to historical samples?

John Ingram: The probabilities are calculated using what we refer to as an ensemble streamflow prediction system. This system produces an ensemble of equally likely to occur streamflow events. These events are generated through the incorporation of hydrologic models and meteorologic and climatologic predictions.

Statistics are performed upon the generated ensemble of streamflow forecasts. In result, we receive information regarding the relative likelihood for river levels to be exceeded during a future window of time. This is an extension of our existing short-term forecasting capabilities. A significant advancement is that AHPS incorporates further precipitation and climate forecasts.

Question:
Bob Halliday: John could you chat a little about the nature of the underlying models --- lumped vs. distributed, etc.

John Ingram: The NWS is implementing an advanced physically based watershed model which segments the watershed. Some academics consider this model to be a type of distributed model, although it is not implemented on a grid.

Question:
Amy Sebring: John, can you tell us what the current status is of your budget request and if approved what you are looking at for implementation timeline?

John Ingram: The AHPS budget is presently under review by Congress. AHPS is in the President's FY2000 budget request to Congress.

Question:
Amy Sebring: Are you scheduled for any committee hearings and are their any key Congressmen?

John Ingram: We have been asked questions from key members and we have been addressing their interests. Key Members are in the Commerce, Justice, State subcommittee of the Appropriation Committees. And delegations from the states of the previous indicated initial implementation areas. The timeline for full implementation is dependent upon approved budgets in current and future years.

Amy Sebring: Thank you John. I am watching my clock but I would like to give Noreen an opportunity to add any comments she may have. Noreen?

Noreen Schwein: We're glad in Central Region to have had the test site at DMX and look forward to future development, and hopefully showing increased savings in life and property!

Amy Sebring: Again, our thanks to all of you, and thanks to our members for joining us. We will officially close the session, but you are invited to remain a few minutes longer for some off-the-record open discussion.