5/19/22
AIM
description and axis, the watch expiration time, a
description of hail size and thunderstorm wind gusts
expected, the definition of the watch, a call to action
statement, a list of other valid watches, a brief
discussion of meteorological reasoning and technical
information for the aviation community.
3.
Public Tornado Watch Notification Messages
describe areas where the threat of tornadoes exists. A
Public Tornado Watch Notification Message contains
the area description and axis, watch expiration time,
the term “damaging tornadoes,” a description of the
largest hail size and strongest thunderstorm wind
gusts expected, the definition of the watch, a call to
action statement, a list of other valid watches, a brief
discussion of meteorological reasoning and technical
information for the aviation community. SPC may
enhance a Public Tornado Watch Notification
Message by using the words “THIS IS A
PARTICULARLY DANGEROUS SITUATION”
when there is a likelihood of multiple strong (damage
of EF2 or EF3) or violent (damage of EF4 or EF5)
tornadoes.
4.
Public severe thunderstorm and tornado
watch notification messages were formerly known as
the Severe Weather Watch Bulletins (WW). The
NWS no longer uses that title or acronym for this
product but retains WW in the product header for
processing by weather data systems.
EXAMPLE
−
Example of a Public Tornado Watch Notification
Message:
WWUS20 KWNS 050550
SEL2
SPC WW 051750
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 243
NWS STORM PREDICTION CENTER NORMAN OK
1250 AM CDT MON MAY 5 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED
A
*TORNADO WATCH FOR PORTIONS OF
WESTERN AND CENTRAL ARKANSAS
SOUTHERN MISSOURI
FAR EASTERN OKLAHOMA
*EFFECTIVE THIS MONDAY MORNING FROM 1250
AM UNTIL 600 AM CDT.
...THIS IS A PARTICULARLY DANGEROUS SITUA-
TION...
*PRIMARY THREATS INCLUDE
NUMEROUS INTENSE TORNADOES LIKELY
NUMEROUS SIGNIFICANT DAMAGING WIND GUSTS
TO 80 MPH LIKELY
NUMEROUS VERY LARGE HAIL TO 4 INCHES IN
DIAMETER LIKELY
THE TORNADO WATCH AREA IS APPROXIMATELY
ALONG AND 100 STATUTE MILES EAST AND WEST OF
A LINE FROM 15 MILES WEST NORTHWEST OF FORT
LEONARD WOOD MISSOURI TO 45 MILES SOUTH-
WEST OF HOT SPRINGS ARKANSAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64
KWNS WOU2).
REMEMBER...A TORNADO WATCH MEANS CONDI-
TIONS ARE FAVORABLE FOR TORNADOES AND
SEVERE THUNDERSTORMS IN AND CLOSE TO THE
WATCH AREA. PERSONS IN THESE AREAS SHOULD
BE ON THE LOOKOUT FOR THREATENING WEATH-
ER CONDITIONS AND LISTEN FOR LATER
STATEMENTS AND POSSIBLE WARNINGS.
OTHER WATCH INFORMATION...THIS TORNADO
WATCH REPLACES TORNADO WATCH NUMBER 237.
WATCH NUMBER 237 WILL NOT BE IN EFFECT
AFTER
1250 AM CDT. CONTINUE...WW 239...WW 240...WW
241...WW 242...
DISCUSSION...SRN MO SQUALL LINE EXPECTED TO
CONTINUE EWD...WHERE LONG/HOOKED
HODOGRAPHS SUGGEST THREAT FOR EMBEDDED
SUPERCELLS/POSSIBLE TORNADOES. FARTHER
S...MORE WIDELY SCATTERED
SUPERCELLS WITH A THREAT FOR TORNADOES
WILL PERSIST IN VERY STRONGLY DEEP SHEARED/
LCL ENVIRONMENT IN AR.
AVIATION...TORNADOES AND A FEW SEVERE THUN-
DERSTORMS WITH HAIL SURFACE AND ALOFT TO 4
INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI
WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 26045.
5.
Status reports are issued as needed to show
progress of storms and to delineate areas no longer
under the threat of severe storm activity. Cancellation
bulletins are issued when it becomes evident that no
severe weather will develop or that storms have
subsided and are no longer severe.
h. Center Weather Advisories (CWAs)
1.
CWAs are unscheduled inflight, flow control,
air traffic, and air crew advisory. By nature of its short
lead time, the CWA is not a flight planning product.
It is generally a nowcast for conditions beginning
within the next two hours. CWAs will be issued:
(a)
As a supplement to an existing SIGMET,
Convective SIGMET or AIRMET.
Meteorology
7
−
1
−
17