Damaging Winds in Tennessee, May 9, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1045 AM CDT TUE MAY 9 2006

.UPDATE...
STRATUS MOVED INTO MID TN EARLY THIS MORNING WITH SFC HIGH IN THE
CAROLINAS. MODELS SHOW PRES GRAD AND B/L MIXING INCREASE INTO THE
MID AFTERNOON HOURS ACR MID TN...SO STRATUS SHOULD SCOUR W OF PLAT
AND CU FORM. THERE WILL BE MORE AFTERNOON HEAT/INSTABILITY IN W
MID TN WITHOUT THE MORNING STRATUS.

MOST RECENT MODEL DATA SHOWS H8 FLOW DECREASES INTO N ARKANSAS MCS
THIS AFTERNOON. DESTABILIATION MAY OFFSET THIS IN W MID TN...AND
WILL UPDATE FORECAST TO INCREASE RW/TRW CHC IN THIS REGION. ALSO
ADDED MORE CLOUDS IN THE PLATEAU. NO OTHER CHANGES AT THIS POINT.

&&

.PREV DISCUSSION... (ISSUED 328 AM CDT TUE MAY 9 2006)

SHORT TERM...IT WAS MOSTLY CLEAR AND COOL ACROSS MIDDLE TENNESSEE
OVERNIGHT, WITH TEMPERATURES DROPPING TO AROUND 50 DEGREES AT MOST
LOCATIONS.

EXPECT AN UPPER LEVEL SHORTWAVE TO MOVE ACROSS THE AREA TODAY AND
PRODUCE THE POTENTIAL FOR SCATTERED, MAINLY AFTERNOON, THUNDERSTORMS.
THE BEST CHANCE SHOULD BE IN OUR NORTHWESTERN COUNTIES, AROUND
CLARKSVILLE AND DOVER, WHERE WE WILL KEEP A 50% POP RUNNING FOR
TODAY. WILL KEEP A 40% POP RUNNING ELSEWHERE.

RECENT RUNS OF THE GFS HAS BEEN INCREASINGLY PROGRESSIVE WITH
MOVEMENT OF NEXT COLD AND HAVE CONTINUED THIS TREND IN THE GRIDS
FOR WEDNESDAY THROUGH THURSDAY. BY LATE WEDNESDAY MORNING, THE FRONT
IS KNOCKING ON OUR BACKDOOR, WITH INSTABILITY AXIS PUSHING INTO OUR
WESTERN COUNTIES. BY LATE WEDNESDAY AFTERNOON, THE FRONT WILL LIKELY
HAVE ALREADY PUSHED PAST CLARKSVILLE, WITH THUNDERSTORMS RUMBLING
OVER MUCH OF OUR FORECAST AREA. BY 06Z, THURSDAY, THE FRONT IS
ALREADY EAST OF THE CUMBERLAND PLATEAU, WITH RAIN CHANCES DROPPING
INTO THE 10-20% RANGE BY LATE LATE THURSDAY NIGHT FOR THE WESTERN
TWO-THRIDS OF MIDDLE TENNESSEE. AS IS USUAL FOR THIS TIME OF YEAR,
BELIEVE SOME STORMS COULD BECOME SEVERE, WITH DAMAGING WINDS AND HAIL.

PWAS INCREASE TO OVER 1.5 AS THE COLD FRONT MOVES IN AND EXPECT SOME
TOAD-STRANGLING DOWNPOURS (ALSO TYPICAL FOR THIS TIME OF YEAR) TO
ACCOMPANY THE THUNDERSTORMS AS THEY SWING THROUGH. THE GOOD NEWS
IS THAT EVEN THOUGH THE HEAVY RAINS COME IN WITH A FURY, THEY
LEAVE IN A HURRY.

BY THURSDAY AFTERNOON, STRONG UPPER TROUGH AXIS EXTENDS FROM THE GREAT
LAKES ALL THE WAY SOUTH INTO THE NORTHERN GULF OF MEXICO, AND IS POISED
TO PROPEL ANOTHER COLD FRONT SOUTHEASTWARD TOWARD THE MID STATE.
BY THAT TIME, WET-BULB ZERO VALUES IN OUR AREA HAVE DECREASED TO
UNDER 7000 FT ASL. THUS, ANY THUNDERSTORMS THAT POP THURSDAY
AFTERNOON ARE LIKELY TO BE HAILERS.

LONG TERM...AN INTERESTING AND SOMEWHAT ODD SPRING WEATHER
PATTERN DEVELOPS IN THE EXTENDED PERIOD, AS UPPER LOW DIVES SOUTH
SOUTHEASTWARD FROM MINNESOTA TO CENTRAL KENTUCKY BY SUNDAY NIGHT.
EXPECT BANDS OF MOISTURE TO SWING IN WITH THIS LOW, ALONG WITH A
GOOD CHANCE FOR MORE SCATTERED THUNDERSTORMS (LIKELY INFESTED WITH
MORE HAILSTONES). VERY DIFFICULT TO TIME PRECIP AND CLOUDS THAT
WILL COME IN WITH THIS SYSTEM. HOWEVER, BELIEVE A GOOD PART OF THE
WEEKEND WILL BE MOSTLY CLOUDY WITH INTERMITTENT PERIODS OF
THUNDERSTORMS (MAINLY DURING THE AFTERNOON HOURS).

HIGH TEMPERATURES WILL BE UNSEASONABLY COOL, AS COLD CORE LOW SINKS
TOWARD OUR AREA, WITH AFTERNOON TEMPERATURES LIKELY GETTING NO
HIGHER THAN THE 60S IN MOST LOCATIONS SATURDAY THROUGH MONDAY.

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

04

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
530 AM CDT TUE MAY 9 2006

TNZ005>011-022>034-056>066-075-077>080-093>095-101030-
BEDFORD-BENTON-CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND-DAVIDSON-
DEKALB-DICKSON-FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON-HUMPHREYS-
JACKSON-LAWRENCE-LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY-OVERTON-PERRY-
PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART-SUMNER-TROUSDALE-
VAN BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON-
530 AM CDT TUE MAY 9 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF MIDDLE
TENNESSEE.

.DAY ONE...TODAY AND TONIGHT

AN APPROACHING WEATHER SYSTEM WILL SPREAD SCATTERED STORMS ACROSS
MIDDLE TENNESSEE TODAY AND TONIGHT, WITH A SLIGHT RISK OF SEVERE
WEATHER BEING HIGHLIGHTED OVER SUCH AREAS AS CLARKSVILLE, DICKSON,
LAWRENCEBURG, WAYNESBORO, WAVERLY, DOVER, AND CAMDEN.

SOME OF THE STORMS THAT DO DEVELOP MAY STRENGTHEN INTO SEVERE CELLS,
WITH DAMAGING DOWNBURST WINDS AND LARGE HAIL BEING THE PRIMARY
THREATS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A COLD FRONT IS EXPECTED TO APPROACH THE MID STATE ON WEDNESDAY, AND
PASS THROUGH WEDNESDAY EVENING. THUNDERSTORMS WILL INCREASE, AS ALL
OF MIDDLE TENNESSEE IS UNDER A SLIGHT RISK OF SEVERE STORMS ON
WEDNESDAY AND WEDNESDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTERS AND EMERGENCY MANAGERS MAY NEED TO BE ACTIVATED
THIS AFTERNOON AND EVENING, AND ALSO ON WEDNESDAY AND WEDNESDAY
NIGHT.

ROSE