Today marks the first day of the 2014 Hazardous Weather Testbed (HWT) Spring Experiment, which will run through the first week in June (Experimental Warning Program (EWP) Big Spring Experiment will be off for Memorial Day week). The HWT provides the GOES-R Proving Ground with an opportunity to demonstrate baseline and future capabilities products associated with the next generation GOES-R geostationary satellite system that have the potential to improve short-range hazardous weather nowcasting and forecasting. The availability of GOES-R products will demonstrate, pre-launch, a portion of the full observing capability of the GOES-R system, subject to the constraints of existing data sources to emulate the satellite sensors.
GOES-R products being evaluated this year include: Synthetic Satellite Imagery, NearCast System, Convective Initiation, Probability of Severe Model, Overshooting Top Detection, PGLM Total Lightning products, Tracking Tool and Lightning Jump Algorithm. These products will be demonstrated by National Weather Service forecasters and broadcast meteorologists within a simulated warning operations environment using a real-time AWIPS-II framework within the HWT EWP. When and if appropriate and if time permits, several of these products may be demonstrated informally in the HWT Experimental Forecast Program (EFP) during the mid-afternoon when the EFP severe storm forecasts are being updated.
As in previous years, participants, in addition to myself and visiting scientists, will make frequent posts to the following blog regarding the days activities, product performance, product feedback, etc.: http://www.goesrhwt.blogspot.com/
– Bill Line, SPC/HWT Satellite Liaison
The storms that ravaged the southern United States this past week not only produced deadly severe weather, but also incredible flooding. Figure 1 shows parts of the Florida Panhandle and southern Alabama received in excess of 10 inches of rain on Tuesday, April 29 alone!
Figure 1: April 29 12Z to April 30 12Z precipitation analysis. More negative values indicate stronger OT’s
A previous blog post introduced the Overshooting Top Detection product and explained its utility in severe weather situations. Overshooting tops are also indicators of where heavy rainfall may be occurring. Furthermore, the constant presence of overshooting tops over a particular location over an extended period of time may indicate a prolonged period of heavy rainfall, which could lead to flooding.
The animation in Figure 2 shows GOES-East IR imagery with overshooting top detection’s overlaid from the afternoon of the April 29 into the early morning hours of the April 30. During much of this period, GOES-East was in Rapid Scan Mode, meaning images were often available every 5-10 minutes (instead of 15). Notice the persistence of overshooting tops centered over the Mobile area throughout the period, where copious amounts of rainfall were recorded. By about 09Z, a downward trend in overshooting top detection’s had begun as the storm system shifted eastward and weakened. The Overshooting Top Detection product provides a day/night capability for forecasters to easily identify where within a convective system the strongest updrafts are occurring, and where severe weather and/or heavy rainfall may be occurring given other meteorological factors.
Figure 2: April 29 22Z – April 30 10Z GOES-East IR with Overshooting Top Magnitude overlaid.
Figure 3 shows this same system during the early morning hours of April 30 at much higher resolution. This is a 375 m IR image taken with the Suomi NPP VIIRS instrument. Notice the visibility of features that aren’t easily seen in current GOES IR imagery such as gravity waves and overshooting tops.
Figure 3: April 30 0645Z Suomi NPP VIIRS 375 m IR
– Bill Line, SPC/HWT GOES-R Satellite Liaison