Severe Thunderstorm Warning 227, NWS Nashville, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
250 PM CDT THU JUL 20 2000

ZONE GROUPINGS WILL...TO A GREAT EXTENT...BE BASED ON RADAR TRENDS
AND WATCH STATUS NEAR ISSUANCE TIME. MAIN ACTION WILL HIT PERRY AND
WAYNE COUNTIES. THUNDERSTORM INTENSITY EXPECTED TO DIMINISH AS IT
APPROACHES NASHVILLE METRO AREA...HOPEFULLY. GREATEST COVERAGE OF
THUNDERSTORMS WILL BE SOUTH OF METRO AREA. GREATEST INSTABILITY
STILL IN SOUTHWEST PART OF MIDDLE TN. COMPUTED LIFTED INDICES RANGE
FROM ZERO ON NORTH PLATEAU TO -7 IN SOUTHWEST MIDDLE TN. SURFACE
FRONT FROM CENTRAL GA...AL...EAST OF GREENWOOD MS AND INTO CENTRAL
AR. MIDDLE TN SKIES WERE PARTLY CLOUDY WITH READINGS IN THE MID AND
UPPER 80S...EXCEPT NEAR 80 PLATEAU.

THROUGH THIS FORECAST PERIOD...THE UPPER LEVEL RIDGE WILL SHARPEN
OVER THE ROCKIES WHILE THE EASTERN TROUGH DEEPENS. MIDDLE TN WILL BE
UNDER A NORTHWEST FLOW WITH POCKETS OF ENERGY DIGGING INTO THE BASE
OF THE LONG WAVE TROUGH. MODELS ARE ALL OVER THE PLACE WITH
VORTICITY CENTERS AND INTENSITIES. AS MENTIONED IN PREVIOUS
DISCUSSIONS...WITH THIS UPPER LEVEL PATTERN NASTY WEATHER COULD OCCUR.
NEGATIVE SIDE FOR EXTREME WEATHER IS THAT WE DO NOT SEEM TO GET INTO
VERY DEEP MOISTURE...AND UPPER LEVEL ENERGY AND FORCING ARE NOT WELL
FOCUSED. FRIDAY WILL BRING GREATER INSTABILITY ACROSS THE AREA THAN
TODAY. CAPES WILL REACH NEAR 2000 WITH LIFTED INDICES -3 TO -5.
PRECIPITABLE WATER REACHES 1.6 AT NASHVILLE. MAIN FORCING WILL BE
FRONT LATE DAY AND FRIDAY NIGHT AS ANOTHER SURFACE FRONT MOVES
THROUGH TN. ALL THAT SAID...WILL HAVE 30-40 POPS FRIDAY AND FRIDAY
NIGHT.

SATURDAY THROUGH THE EXTENDED FORECAST LOOKS VERY NICE WITH HIGHS IN
THE 80S AND LOWS IN THE 60S.

NGM MOS HIGHS LOOK TOO HIGH BASED ON 850 TEMPERATURES AND FORECAST
SOUNDINGS.

BNA 68/88/69/86 3330
CSV 61/83/62/81 -330

.BNA...NONE.
SH

TNZ005>008-022>027-056>060-093-094-202200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
1252 PM CDT THU JUL 20 2000

...SEVERE THUNDERSTORM WATCH FOR WESTERN MIDDLE TENNESSEE TIL 5 PM...

THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH
...FOR AREAS WEST OF A GALLATIN TO NASHVILLE TO COLUMBIA TO
LAWRENCEBURG LINE.

AT 1230 PM...A LINE OF STRONG TO SEVERE THUNDERSTORMS STRETCHED
FROM THE MISSOURI BOOTHEEL TO NORTHEAST ARKANSAS.  THIS ACTIVITY IS
MOVING TO THE EAST AT 40 TO 45 MPH. THE LINE SHOULD MOVE TO A DOVER
TO CAMDEN LINE BETWEEN 230 AND 300 PM.

THE MAIN THREAT WITH THIS LINE WILL BE WITH STRONG DAMAGING WINDS IN
EXCESS OF 60 MPH.  THE OTHER THREATS WILL BE WITH FREQUENT CLOUD TO
GROUND LIGHTNING STRIKES...AND LARGE HAIL UP TO 1 INCH IN DIAMETER.
THE GREATEST THREAT OF SEEING DAMAGING WINDS AND LARGE HAIL WILL BE
OVER BENTON....HUMPHREYS...PERRY...LEWIS AND WAYNE COUNTIES.

DUE TO A VERY STABLE AIRMASS EAST OF NASHVILLE...THE LINE IS
EXPECTED TO WEAKEN RAPIDLY AS IT APPROACHES THE NASHVILLE METRO
AROUND 400 TO 500 PM.

ACTIVATION OF SPOTTERS AND EMERGENCY MANAGERS IS POSSIBLE...
ESPECIALLY WEST OF INTERSTATE 65.

JDG/MD

TNZ005>008-022>027-056>060-093-094-202200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
203 PM CDT THU JUL 20 2000

...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON...

AT 2 PM...A LINE OF STRONG TO SEVERE THUNDERSTORMS STRETCHED
FROM JUST WEST OF THE LAND BETWEEN THE LAKES TO MEMPHIS.  THIS
ACTIVITY IS MOVING TO THE EAST AT 40 TO 45 MPH.

THE MAIN THREAT WITH THIS LINE WILL BE WITH STRONG DAMAGING WINDS IN
EXCESS OF 60 MPH.  DAMAGING WINDS HAVE BEEN REPORTED IN THE MEMPHIS
METRO AREA AROUND 2 PM. THE OTHER THREATS WILL BE WITH FREQUENT
CLOUD TO GROUND LIGHTNING STRIKES...AND LARGE HAIL UP TO 1 INCH IN
DIAMETER. THE GREATEST THREAT OF SEEING DAMAGING WINDS AND LARGE HAIL
WILL BE OVER BENTON....HUMPHREYS...PERRY...LEWIS AND WAYNE COUNTIES.

DUE TO A VERY STABLE AIRMASS EAST OF NASHVILLE...THE LINE IS
EXPECTED TO WEAKEN RAPIDLY AS IT APPROACHES THE NASHVILLE METRO
AROUND 400 TO 500 PM.

ACTqIVATION OF SPOTTERS AND EMERGENCY MANAGERS IS POSSIBLE...
ESPECIALLY WEST OF INTERSTATE 65.

JDG