; (ii) the members of the Senate representing the States affected by the incident; and (iii) the members of the House of Representatives representing the congressional districts affected by the incident; and (B) update the initial notification under paragraph (1) within a reasonable period of time after additional information relating to the incident is discovered. (2) Reporting threshold The Secretary shall— (A) promulgate a uniform definition of a significant election cybersecurity incident ; and (B) shall submit the definition promulgated under subparagraph (A) to the appropriate congressional committees. 5. Advisory panel and guidelines (a) Advisory Panel (1) In general The Secretary shall establish an advisory panel of independent experts on election cybersecurity. (2) Membership The Advisory Panel shall consist of not less than 9 members, of whom— (A) 5 shall be appointed by the Secretary, in consultation with the Chairman and the Director of the National Institute of Standards and Technology, of whom 1 shall be designated as the Chairperson of the Advisory Panel; (B) 1 shall be appointed by the National Association of Secretaries of State; (C) 1 shall be appointed by the National Association of State Election Directors; (D) 1 shall be appointed by the National Association of Counties; and (E) 1 shall be appointed by the National League of Cities. (3) Eligibility Individuals appointed to the Advisory Panel established under paragraph (1)— (A) may not be officers or employees of the United States; (B) if appointed under paragraph (2)(A), shall possess expertise in cybersecurity; and (C) if appointed under any other subparagraph of paragraph (2), shall possess expertise in cybersecurity, election law, or election administration. (4) Terms