Real Time All-weather Precipitable Water Product Development from Geostationary Infrared Radiances and Applications in Weather Forecasts

Observations of moisture transportation in pre-convection environment and during storm development are very useful for forecasters. NOAA's next generation of Geostationary Operational Environmental Satellite (GOES-R) series provides high temporal (every 5 minutes) and spatial (2 km) resolution moisture information not seen before. Since there will be no sounder onboard the GOES-R series, the GOES-R ABI will be used to continue the current GOES Sounder legacy atmospheric profile (LAP) products. However, the current GOES Sounder and the next GOES-R operational LAP products are only available in clear skies. Extending the use of IR measurements into cloudy regions would increase the completeness of moisture information. In typical scenes, completely clear-sky observations from the infrared (IR) observations are available for only 10 – 50% of the image, depending on the spatial resolution. Studies show that cloudy regions are more responsible for the development of error in NWP forecasts and exhibit more forecast error than clear skies. In order to obtain moisture information also in cloudy regions, an algorithm has been developed for all-weather real time total precipitable water (TPW) and three layer precipitable water (LPW: surface - 0.9, 0.9 – 0.7, and 0.7 – 0.3 in sigma coordinate) retrievals by combining infrared radiances and numerical weather prediction (NWP) model forecasts. Validation against ground-based in-situ measurements shows that TPW over low cloud, thin cloud or broken cloud regions have better accuracy than NWP forecasts. The algorithm has been implemented for GOES-13/-15 Sounder real time processing and the TPW/LPW products have been made available in near real time (NRT) into the Advanced Weather Interactive Processing System (AWIPS II) to allow operational meteorologists to monitor a controlling ingredient in the initiation, development, and decay of convective cells and systems. The unique TPW/LPW products have the advantages of availability in all sky weather conditions. Examples from GOES-R Proving Ground (PG) at the Hazardous Weather Testbed (HWT) taken place from 04 May to 12 June 2015 are discussed to demonstrate the forecast applications of this very useful product. Results from other GEO systems such as AHI (Advanced Himawari Imager) by applying this algorithm are also presented.