Section 10. Meteorological Impact Statement (MIS)
A Meteorological Impact Statement (MIS) is an
unscheduled planning forecast. It is an air traffic
oriented forecast intended for ARTCC, Air Traffic
Control System Command Center Weather Unit
(DCCWU), Air Traffic Control System Command
Center (ATCSCC), and hub terminal air traffic
facility specialists responsible for making flow
control and flow control-related decisions. It enables
these specialists to include the impact of expected,
specified local and/or national weather conditions in
making these decisions.
a. The MIS describes adverse weather conditions
which are expected to begin generally within 4-to-12
hours after the statement's issuance. It can also
describe conditions existing when the CWSU begins
daily operations if the existing conditions will
continue for at least 3 hours, or it can describe
conditions existing at the time a briefing is issued. As
a minimum, an MIS will be issued when:
1. Any of the following conditions occur or are
forecast to occur:
(a) Conditions meeting Convective SIGMET
criteria. (See National Weather Service Instruction
(b) Moderate or greater icing.
(c) Moderate or greater turbulence.
(d) Heavy precipitation.
(e) Freezing precipitation.
(f) Conditions at, or approaching, low IFR.
(See National Weather Service Instruction 10-813.)
(g) Surface winds, including gusts of 30 knots
(h) Low level wind shear (within 2,000 feet of
(i) Volcanic ash, dust storms, or sandstorms.
National Weather Service Instruction 10-803, Support to Air Traffic
2. The above conditions will, in the forecaster's
judgment, impact the flow of air traffic within the
ARTCC area of responsibility.
3. The forecast lead time (the time between the
issuance of an MIS and the onset of the
phenomenon), in the forecaster's judgment, is
sufficient to make the issuance of a CWA premature
b. The MIS will describe the location of the
phenomenon using ARTCC relevant points of
reference, such as VORs, and will include the height,
extent, intensity, and movement of the phenomenon.
MISs will be numbered sequentially, beginning at
midnight local time each day. Forecasters should be
aware that the MIS is disseminated and stored as a
replaceable product. This means that each MIS
issuance must contain all of the pertinent and known
details of the conditions meeting MIS issuance
criteria including the continuing conditions described in previously issued MISs.
c. The format of the MIS communications header
is: (ARTCC designator) MIS (issuance number)
VALID (issuance date/time-valid until date/time in
UTC)/..FOR ATC PLANNING PURPOSES
ZJX MIS 02 VALID 111345-120100
..FOR ATC PLANNING PURPOSES ONLY..
SCT TSTMS WITH HVY PCPN ALG N/S RTES S OF ILM
AND E OF SAV/OMN LN DVLPG BY 16Z MAX TOPS
350/400. ELSW ZJX AREA TSTMS WITH HVY PCPN
FRMG IN SHRT LNS OR CLUSTERS AFT 17Z WITH
FEW RCHG EXTRM. CELLS MOVG GENLY SEWD 10
KTS CONT THRU 00Z CONDS LWRG OCNLY TO LIFR
IN HVY PCPN AFT 17Z.
The MIS will be distributed to ARTCC area
supervisors and traffic management coordinators and
will be entered through FAA AISR and other
communications media to make it available for
dissemination to other FAA and NWS facilities,
including adjacent CWSUs and locally designated
hub terminal facilities. Distribution may be made
directly by the CWSU meteorologist or through the
weather coordinator position. When a MIS is issued
concurrently with a briefing, the MIS will be
distributed through those media to facilities
mentioned above which do not receive an
alphanumeric version of the briefing's contents.