The stevens flood advisory system: operational H3E flood forecasts for the greater New York / New Jersey Metropolitan Region

Abstract

This paper presents the automation, website interface, and verification of the Stevens Flood Advisory System (SFAS, http://stevens.edu/SFAS). The fully-automated, ensemble-based flood advisory system dynamically integrates real-time observations and river and coastal flood models forced by an ensemble of meteorological models at various scales to produce and serve street scale flood forecasts over urban terrain. SFAS is applied to the Greater NY/NJ Metropolitan region, and is used routinely by multiple forecast offices and departments within the US National Weather Service (NWS), regional and municipal Offices of Emergency Management, as well as the general public. Every six hours, the underlying H 3 E (Hydrologic-Hydraulic-Hydrodynamic Ensemble) modelling framework, prepares, runs, data-assimilates, and integrates results from 375 dynamic model simulations to produce actionable, probabilistic ensemble forecasts of upland and coastal (storm surge) flooding conditions with an 81-h forecast horizon. Meteorological forcing to the H 3 E models is provided by 125 weather model ensemble members as well as deterministic weather models from major weather agencies (NCEP, ECMWF, CMC) and academia. The state-of-the-art SFAS, a replacement of the well-known, but deterministic, Storm Surge Warning System (SSWS) that was highlighted during Hurricanes Irene and Sandy and more recently extratropical cyclone Jonas, has been operational since the end of 2015.

Storm Surge Barrier Protection in an Era of Accelerating Sea-Level Rise: Quantifying Closure Frequency, Duration and Trapped River Flooding

“…In the practical operation of the surge barrier system, decisions on gate closure will be based on forecasts of future water levels, which will always have uncertainty. Notably, the forecast water level uncertainty is usually larger for more extreme events, such as deep extratropical low-pressure systems or hurricanes (e.g., [19,20]). The forecast water level needs to come 24 h or even earlier in advance of the projected flooding event giving time for the cumbersome gate closure operation before the event hits.…”

“…We quantify typical uncertainty in water-level forecasts and its dependence on storm surge by utilizing the past 4 years of forecast results from an operational forecast system [19,21]. The 95th percentile forecast is chosen as a hypothetical value for barrier closure decisions, which leads to a probability of 5% of false negatives.…”

Using a WRF-ADCIRC Ensemble and Track Clustering to Investigate Storm Surge Hazards and Inundation Scenarios Associated with Hurricane Irma

“…Here, we extend dynamical ensemble TC forecasting into the hazard space to explore the anticipated uncertainty and potential information content in different aspects of storm surge forecasts. Although several previous studies have used dynamical atmosphere-surge ensembles to explore coastal flood prediction (e.g., Flowerdew et al 2010Flowerdew et al , 2013Di Liberto et al 2011;Colle et al 2015;Georgas et al 2016;Dietrich et al 2018), limited work has focused on understanding the characteristics and potential utility of dynamical TC-surge ensemble forecasts.…”

The Practical Predictability of Storm Tide from Tropical Cyclones in the Gulf of Mexico

“…The National Hurricane Center (NHC) has recently developed new storm surge watch, warning, and probabilistic inundation products, but these storm-specific surge forecast products are not currently issued more than 48 h in advance of anticipated landfall because of the limited predictability of the hurricane's track, and thus of storm surge at different coastal locations (NHC 2017). An indication of the uncertainty in these predictions is the recent development of ensemble prediction systems for surge both in research (Di Liberto et al 2011;Colle et al 2015;Georgas et al 2016) and in operations [the creation of the NHC's new probabilistic surge (P-Surge) products; Taylor and Glahn 2008].…”