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AIM

10/12/17

7−1−16

Meteorology

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.

(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 condi-

tions.

(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.