AIM
4/3/14
7−1−18
Meteorology
THE TORNADO WATCH AREA IS ALONG AND 60
STATUTE MILES NORTH AND SOUTH OF A LINE
FROM 50 MILES SOUTHWEST OF RATON NEW
MEXICO TO 50 MILES EAST OF AMARILLO TEXAS.
REMEMBER...A TORNADO WATCH MEANS CON-
DITIONS 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...CONTINUE...
WW 378...WW 379...WW 380
DISCUSSION...THUNDERSTORMS ARE INCREASING
OVER NE NM IN MOIST SOUTHEASTERLY UPSLOPE
FLOW. OUTFLOW BOUNDARY EXTENDS EASTWARD
INTO THE TEXAS PANHANDLE AND EXPECT STORMS
TO MOVE ESE ALONG AND NORTH OF THE
BOUNDARY ON THE N EDGE OF THE CAP. VEERING
WINDS WITH HEIGHT ALONG WITH INCREASGING
MID LVL FLOW INDICATE A THREAT FOR SUPER-
CELLS.
AVIATION...TORNADOES AND A FEW SEVERE THUN-
DERSTORMS WITH HAIL SURFACE AND ALOFT TO 2
3
/
4
INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI
WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 28025.
6.
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.
7.
When tornadoes or severe thunderstorms
have developed, the local WFO office will issue the
warnings covering those areas.
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.
(b)
When an Inflight Advisory has not been
issued but observed or expected weather conditions
meet SIGMET/AIRMET criteria based on current
pilot reports and reinforced by other sources
of information about existing meteorological
conditions.
(c)
When observed or developing weather
conditions do not meet SIGMET, Convective
SIGMET, or AIRMET criteria; e.g., in terms of
intensity or area coverage, but current pilot reports or
other weather information sources indicate that
existing or anticipated meteorological phenomena
will adversely affect the safe flow of air traffic within
the ARTCC area of responsibility.
2.
The following example is a CWA issued from
the Kansas City, Missouri, ARTCC. The “3” after
ZKC in the first line denotes this CWA has been
issued for the third weather phenomena to occur for
the day. The “301” in the second line denotes the
phenomena number again (3) and the issuance
number (01) for this phenomena. The CWA was
issued at 2140Z and is valid until 2340Z.
EXAMPLE
−
ZKC3 CWA 032140
ZKC CWA 301 VALID UNTIL 032340
ISOLD SVR TSTM over KCOU MOVG SWWD
10 KTS ETC.
7
−
1
−
7. Categorical Outlooks
a.
Categorical outlook terms, describing general
ceiling and visibility conditions for advanced
planning purposes are used only in area forecasts and
are defined as follows:
1. LIFR (Low IFR).
Ceiling less than 500 feet
and/or visibility less than 1 mile.
2. IFR.
Ceiling 500 to less than 1,000 feet
and/or visibility 1 to less than 3 miles.
3. MVFR (Marginal VFR).
Ceiling 1,000 to
3,000 feet and/or visibility 3 to 5 miles inclusive.
4. VFR.
Ceiling greater than 3,000 feet and
visibility greater than 5 miles; includes sky clear.
b.
The cause of LIFR, IFR, or MVFR is indicated
by either ceiling or visibility restrictions or both. The
contraction “CIG” and/or weather and obstruction to
vision symbols are used. If winds or gusts of 25 knots
or greater are forecast for the outlook period, the word
“WIND” is also included for all categories including
VFR.
EXAMPLE
−
1. LIFR CIG
−low IFR due to low ceiling.
2. IFR FG
−IFR due to visibility restricted by fog.