13B.3 Issuing Warnings with No Radar

Thursday, 16 January 2020: 2:00 PM
253B (Boston Convention and Exhibition Center)
David E. Levin, NOAA/NWS, Juneau, AK

Forecasting and monitoring convection in Southeast Alaska is greatly complicated by the scarcity of observations, no radar coverage, and extremely complex terrain. Thunderstorms also occur relatively infrequently due to the proximity of cool, stable marine air. With the advent of satellite imagery with better temporal and spatial resolution as well as improved lightning detection, it has now become possible to better analyze thunderstorm strength and evolution in Southeast Alaska. This talk will examine the thought process and analysis that went into the decision to issue the first ever Severe Thunderstorm Warning from the NWS Weather Forecast Office in Juneau, Alaska on June 27, 2019. Best practices for forecasters monitoring convection with limited/no radar include pro-actively requesting one minute meso-sectors ahead of convective events, a thorough examination of pre-storm environments to anticipate hazard type, and using IR brightness temp as well as lightning jump concepts to determine updraft strength and size. While still very challenging, it is now possible with GOES 17 and more frequent polar orbiting imagery to monitor and warn on severe weather in areas where there is limited/no radar coverage.
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