What is a PDS?
Particularly Dangerous Situation. When a situation is
labeled as a "PDS" , either on a risk or just for a particular watch,
significant severe is expected. Large, long tracked tornadoes,
very high winds and/or exceptionally large hail is what is expected
to occur.
The Watches
The Aviation/Preliminary Watch
The old public watch format
WWUS9 KMKC 231123
WWUS40 KMKC 162236
MKC AWW 162236
WW 1162 SEVERE TSTM MS AL FL AND ADJ CSTL WTRS 162300Z - 170400Z
AXIS..75 STATUTE MILES NORTH AND SOUTH OF LINE..
45SW MOB/MOBILE AL/ - 30SSE DHN/DOTHAN AL/
..AVIATION COORDS.. 65NM N/S /37SW MOB - 51WNW TLH/
HAIL SURFACE AND ALOFT..1 1/4 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 400. MEAN WIND VECTOR 23035.
The Public Watch Issuence
45SSW MOB/MOBILE AL/-30SSE DHN/DOTHAN AL/
Theses are the coordinates for the watch box area. One point is
at 45 miles south-southwest of Mobile and the other is 30 miles south-
southeast of Dothan. Connect those dots. Then draw a line 75 miles
north and 75 miles south from each point. Simply connect the the
rest to form the box. Sometimes it might be East and West of a line
and other times it will just be either side of a line (just draw
the lines perpendicular to the axis line).
SEL0
MKC WW 231123
FLZ000-231800-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 190
STORM PREDICTION CENTER NORMAN OK
723 AM EDT WED APR 23 1997
THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
The location...
NORTHERN AND CENTRAL FLORIDA
AND ADJACENT COASTAL WATERS
The valid time...
EFFECTIVE THIS WEDNESDAY MORNING AND AFTERNOON FROM 800 AM UNTIL
200 PM EDT.
What to expect...
TORNADOES...HAIL TO 1 1/2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
The exact coordinates...
THE TORNADO WATCH AREA IS ALONG AND 90 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 60 MILES SOUTH SOUTHWEST OF CROSS CITY FLORIDA
TO 45 MILES EAST SOUTHEAST OF DAYTONA BEACH FLORIDA
.
Other watches currently valid in th US...
OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO WATCH
NUMBER 189. WATCH NUMBER 189 WILL NOT BE IN EFFECT AFTER 800 AM
EDT.
Call to action statement...
REMEMBER...A TORNADO WATCH MEANS CONDITIONS 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
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.
Meteorological Discussion...
DISCUSSION...THREAT FOR SUPERCELL TORNADOES SHOULD CONTINUE THROUGH
THE EARLY AFTERNOON HOURS...GIVEN UNSEASONABLY STRONG VERTICAL
SHEAR AND MODERATE-STRONG INSTABILITY.
Aviation Meteorological Discussion...
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 1/2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 26030
.
The forecaster...
...VESCIO
The exact lat/lon of the four points(corners) of the
watch box
;300,0832 301,0802 273,0802 273,0832;
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