Damaging Wind in Tennessee, April 15, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
425 AM EDT SUN APR 15 2001

15/00Z MODELS ARE NOW INDICATING THAT S/W ENERGY APPROACHING THE MID
MISSISSIPPI RIVER VALLEY WILL BE THE DOMINANT WEATHER FEATURE
AFFECTING THE FORECAST AREA TODAY AND TONIGHT...WITH SHOWERS AND
THUNDERSTORMS THROUGH THE EARLY SECOND PERIOD. IN PARTICULAR...
FOR THIS AFTERNOON AND EARLY EVENING...IMPRESSIVE 1000/850-MB QG
FORCING PHASES WITH A DEVELOPING THETA-E RIDGE...AS A COLD FRONT IS
DRAGGED SOUTH OF THE BACK SIDE OF THE DOMINANT U/L S/W. ETA CAPES AND
LI/S BECOME STRONGLY UNSTABLE JUST AHEAD OF THE FRONT ~ 00Z...AND
LOW-LAYER SHEAR SUPPORTS THE POTENTIAL FOR WIND DAMAGE.

THEN...EXPECT POST-FRONTAL PARTIAL CLEARING CENTRAL/SOUTH WITH
CLOUDS HOLDING TOUGHER IN THE NORTHEAST.

MONDAY...A VERY STRONG ARCTIC COLD FRONT PUSHES THROUGH THE FORECAST
AREA IN THE P.M., WITH VERY COLD TEMPERATURES ALOFT POISED JUST TO
THE NORTH. H8 TEMPERATURES FALL CLOSE TO -10 C IN THE NORTH BY
17/12Z...PRODUCING SOME L/L INSTABILITY AND A SWATH OF HIGH R/H.
WILL LOWER TUESDAY MORNING TEMPERATURES...AND CALL FOR A CHANCE
POP OF RW/SW ALL THE WAY DOWN INTO THE SOUTHERN MOUNTAINS (UPSLOPE
FLOW SUPPORTS THIS EXTENSION).

BASICALLY ACCEPTED A MOS TEMPERATURE BLEND BETWEEN THE MAV AND FWC...
WITH NO FAN VALUES AVAILABLE.

FCSTID = 4
CHA   72  51  70  44 / 100  40   0  10
TYS   70  50  66  41 / 100  40   0  20
TRI  A 69  45  61  38 /  70  40   0  30
OQT   70  50  65  40 / 100  40   0  20

.MRX...
NC...NONE.
TN...NONE.
VA...NONE.

DM

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-005-
006-008-152200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MORRISTOWN TN
600 AM EDT SUN APR 15 2001

...SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE REGION TODAY...

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY ACROSS EAST
TENNESSEE...EXTREME SOUTHWEST NORTH CAROLINA...AND SOUTHWEST
VIRGINIA FROM LATE MORNING THROUGH THIS AFTERNOON.  THE MOST LIKELY
SEVERE WEATHER WILL BE DAMAGING STRAIGHT LINE WINDS.  THERE MAY ALSO
BE HAIL TO ONE INCH IN DIAMETER.  AN ISOLATED TORNADO CAN NOT BE
RULED OUT.

A FAIRLY STRONG UPPER LEVEL SYSTEM AND AN ASSOCIATED COMPLEX FRONTAL
SYSTEM WILL MOVE TOWARD AND THROUGH THE AREA TODAY.  THE BEST
CHANCES FOR SEVERE STORMS WILL BE FROM LATE MORNING TO EARLY
AFTERNOON...AS AN AREA OF PRE-EXISTING STRONG TO SEVERE
THUNDERSTORMS MOVES INTO THE AREA FROM THE WEST.  AS THESE STORMS
MOVE EAST...AIR NEAR THE SURFACE WILL BECOME MORE MOIST AND
WARM...AND COOLER AIR WILL MOVE IN ALOFT.  THIS COMBINATION WILL
RESULT IN A DESTABILIZATION OF THE ATMOSPHERE.  IN
ADDITION...RELATIVELY STRONG WINDS A FEW THOUSAND FEET ABOVE THE
SURFACE WILL MOVE INTO THE AREA.  THESE WINDS MAY BE BROUGHT DOWN TO
THE SURFACE IN THUNDERSTORMS...HELPING INCREASE THE CHANCE OF
DAMAGING WINDS.

STRAIGHT LINE WINDS TO 70 MPH WILL BE POSSIBLE.  HAIL TO ONE INCH IN
DIAMETER WILL ALSO BE POSSIBLE.  FINALLY...AN ISOLATED TORNADO CAN
NOT BE RULED OUT.

SPOTTER ACTIVATION MAY BE NECESSARY LATE THIS MORNING THROUGH THIS
AFTERNOON.  STAY TUNED TO NOAA WEATHER RADIO...OR LOCAL MEDIA
OUTLETS FOR THE LATEST ON THIS POTENTIAL SEVERE WEATHER EVENT.

SP