Severe Thunderstorm Warning 221, NWS Nashville, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
234 PM CDT WED JUL 12 2000

SHOWERS AND THUNDERSTORMS BEGAN DEVELOPING DURING THE EARLY
AFTERNOON HOURS. A FEW SEVERE THUNDERSTORMS WERE ISSUED MAINLY FOR
THE POSSIBILITY OF DAMAGING WIND.

EARLY THIS AFTERNOON A WEAK COLD FRONT/SURFACE TROUGH CONTINUED TO
THE N OF OUR AREA BUT WAS RATHER HARD TO DEFINE IN MSAS DATA. USING
SURFACE EQUIVALENT POTENTIAL TEMPERATURES...IT APPEARS TO EXTEND
FROM S IL AND THEN ACROSS KY AND ON INTO W VA.

OVER THE NEXT FEW PERIODS MODELS FORECAST MID AND UPPER FLOW TO
BECOME MORE NWLY IN OUR REGION. THIS OCCURS DUE TO BUILDING UPPER
RIDGE OVER ROCKY MOUNTAINS AND LOWERING HEIGHTS OVER E GREAT LAKES
AND NEW ENGLAND IN RESPONSE TO SE MOVING SHORT WAVE ACROSS THE
NE.

UPPER HEIGHTS WILL LOWER IN OUR AREA BUT NOT MUCH. THIS WILL CAUSE
THE WEAK COLD FRONT CURRENTLY STILL N OF THE MID STATE TO GRADUALLY
MOVE SE INTO THE MID STATE LATER TONIGHT AND THEN WEAKEN AS IT
CONTINUES MOVING SE INTO MS/AL AND E TN AREAS ON THU.

A TAD WARMER TEMPERATURES ALOFT PARTICULARLY AT 500 MB LEVEL AS WELL
AS SOME DRIER AIR WILL ACT TO SUPRESS CONVECTION ON THU AND FRI OVER
THE MID STATE. WILL HOWEVER KEEP A LOW POP FOR AFTERNOON THUNDERSTORMS
FOR PLATEAU ON THU AS HIGHER 1000/500 MB MEAN RELATIVE HUMIDITY IS
FORECAST TO REMAIN THERE LONGER ALONG WITH SURFACE TROUGH/COLD
FRONT. THU NIGHT AND FRI LOOK DRY WITH DOWNWARD MOTION FORECAST AT
700 MB LEVEL BY BOTH ETA AND NGM.

PRELIMINARY NUMBERS

BNA 74/93/70/95 41--
CSV 70/87/65/89 421-

.BNA...NONE.

STEIGERWALDT