EWP Underway for 2017

The forecasters are spinning up on their WFOs of interest for the afternoon (Boston, MA and Raleigh, NC).  The NOAA/CIMSS ProbSevere in 2017 has been improved based on feedback from previous EWP experiments. For 2017 EWP, forecasters are evaluating ProbSevere 'AllHazards' with specific probabilistic forecasts for severe hail, severe wind, and tornado.

As of mid afternoon, convection was rapidly intensifying in the Raleigh WFO. Figure 1 below shows AWIPS-2 screenshots of ProbSevere evolution between 1848 and 1936 UTC.  The ProbSevere values increased steadily as thunderstorms developed along a low-level convergence zone and then really increased as an outflow boundary moving from SE to NW impacted the storms.  The ProbSevere values were largely due to a wind threat (ProbWind), although close to 1936 UTC the ProbHail values increased markedly with precipitation core intensification (note jumps in MRMS MESH), perhaps owing to interactions with the outflow boundary.  As of this writing severe reports have not been received.

Figure 1.  KRAX 0.5 degree reflectivity and NOAA/CIMSS ProbSevere contours and readout.  Valid 1848 - 1936 UTC 19 Jun 2017.

The EWP Raleigh WFO team are evaluating these storms and have issued experimental severe thunderstorm warnings.

-Sieglaff