Hail and Damaging Winds in Tennessee, May 9, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
330 PM EDT FRI MAY 9 2008

.SHORT TERM...(TONIGHT THROUGH SATURDAY)...DEEP CONVECTION SLOW TO
START THIS AFTERNOON...LOOKS LIKE WARM LAYER HAS INDEED CAPPED LOW
LEVEL INSTABILITY UNTIL UPPER SHORT WAVE CAN ERODE CAP LATER THIS
AFTERNOON INTO THIS EVENING. TWO POSSIBLE ROUNDS OF STORMS...THE
FIRST WITH THE LIFT PROVIDED BY THE SHORT WAVE FROM ABOUT 21Z-03Z
AS IT MOVES THROUGH FROM WEST TO EAST...AND THE SECOND ALONG THE
COLD FRONT THAT SHOULD QUICKLY FOLLOW FROM ROUGHLY 03Z-09Z AS IT
SWEEPS THROUGH FROM THE NORTHWEST.

FAST FLOW WILL BE OVER AREA...SO STORMS SHOULD MOVE QUICKLY TO THE
EAST.  UNDER THE INFLUENCE OF THE SHORT WAVE...WOULD EXPECT COVERAGE
TO BE SCATTERED AND BETTER CHANCES OF LONE CELLS FOR POSSIBLE
ROTATION... BUT AS STORMS MOVE FARTHER EAST INTO OUR CWA BETTER
DENSITY OF CELLS...CELL MERGERS AND CLUSTERING...SO BETTER CHANCES
WEST RATHER THAN EAST FOR LONE SUPERCELLS.  ALONG THE COLD FRONT
BETTER CHANCE OF A LINE OF SHOWERS/STORMS FORMING AND LESS CHANCES
OF ROTATION.

BY DAYBREAK SATURDAY...FRONT AND ITS ASSOCIATED LIFT SHOULD BE OUT
OF THE AREA...BUT LOW CLOUDS EXPECTED TO LINGER THROUGH MUCH OF THE
MORNING...BUT ERODING NW TO SE. WENT VERY CLOSE TO GUIDANCE TEMPS.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)...DEVELOPING SYSTEM OVER
THE NORTHERN ROCKIES AT THIS TIME WILL HAVE MOVED SOUTHEAST INTO THE
SOUTHERN PLAINS BY SATURDAY EVENING. A WEAK COLD FRONT THAT WILL BE
STATIONARY TO THE SOUTH WILL SPREAD CLOUDS WITH SHOWERS AND POSSIBLE
THUNDERSTORMS SATURDAY NIGHT AS A DEEPENING AREA OF LOW PRESSURE AND
COLD FRONT MOVES INTO THE MID MS VALLEY. GFS DEVELOPS A SECONDARY
LOW IN NORTH CAROLINA WITH THE MAIN LOW HOLDING BACK NORTH OF THE
OHIO RIVER WITH THE WRAPPED UP SYSTEM FINALLY MOVING OFF THE MID
ATLANTIC COAST MONDAY. STILL LOOKS LIKE POSSIBILITY OF SEVERE
THUNDERSTORMS SUNDAY AHEAD OF AND ALONG THE FRONT WITH THE STRONG
DYNAMICS. TIMING WILL BE KEY THOUGH AS PRE FRONTAL CONVECTION MOVES
ACROSS MOST OF THE REGION DURING THE MORNING. COOLER NW FLOW AND
WRAP AROUND MOISTURE BEHIND THE FRONT WILL KEEP CLOUDS IN THE NW
SECTIONS THROUGH MONDAY WITH A CHANCE OF SHOWERS CONTINUING. MONDAY
AFTERNOON THROUGH TUESDAY NIGHT HIGH PRESSURE BUILDS IN FOR SOME
DRYING. ANOTHER SIGNIFICANT FRONT APPROACHES WEDNESDAY WITH SHOWERS
AND THUNDERSTORMS AGAIN POSSIBLE UNTIL FRONTAL PASSAGE THURSDAY.
PARENT SURFACE LOW ALSO MOVES SLOWLY EAST ACROSS OHIO VALLEY
THURSDAY AND FRIDAY WITH WRAP AROUND MOISTURE BEHIND SYSTEM FRIDAY
STILL BRINGING CHANCE OF SHOWERS TO THE FORECAST AREA. LOWS WILL BE
COOLER SATURDAY NIGHT WITH EARLY CLEARING AND HIGHS SUNDAY ABOUT 10
DEGREES COOLER THAN SATURDAYS WITH CLOUDS AND SHOWERS MUCH OF THE
DAY. BEHIND THE FRONT SUNDAY NIGHT AND MONDAY FREEZING LEVELS DROP
DOWN TO 6 TO 7 THOUSAND FEET AND HIGH TEMPERATURES WILL STILL BE
COOLER IN THE 60S MOST PLACES. AS RIDGING BUILDS IN TUESDAY AND
WEDNESDAY TEMPERATURES WILL REBOUND BACK TO THE 70S.
&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN  61  80  62  72  49 /  30  10  70  70  20
KNOXVILLE AIRPORT, TN    58  78  58  72  48 /  30  10  60  80  40
OAK RIDGE, TN            57  78  59  71  47 /  40  10  70  80  40
TRI CITIES AIRPORT, TN   54  72  51  67  47 /  40  10  40  70  60
&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

GM/TD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
457 AM EDT FRI MAY 9 2008

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-101000-
CHEROKEE-CLAY-SCOTT TN-CAMPBELL-CLAIBORNE-HANCOCK-HAWKINS-
SULLIVAN-JOHNSON-MORGAN-ANDERSON-UNION-GRAINGER-HAMBLEN-
NORTHWEST COCKE-COCKE SMOKY MOUNTAINS-NORTHWEST GREENE-
SOUTHEAST GREENE-WASHINGTON TN-UNICOI-NORTHWEST CARTER-
SOUTHEAST CARTER-ROANE-LOUDON-KNOX-JEFFERSON-NW BLOUNT-
BLOUNT SMOKY MOUNTAINS-NORTH SEVIER-SEVIER SMOKY MOUNTAINS-
SEQUATCHIE-BLEDSOE-RHEA-MEIGS-MCMINN-NORTHWEST MONROE-
SOUTHEAST MONROE-MARION-HAMILTON-BRADLEY-WEST POLK-EAST POLK-LEE-
WISE-SCOTT-RUSSELL-WASHINGTON-
457 AM EDT FRI MAY 9 2008 /357 AM CDT FRI MAY 9 2008/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST NORTH
CAROLINA...EAST TENNESSEE AND SOUTHWEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

AN UPPER LEVEL DISTURBANCE WILL SWING BY TO OUR NORTH LATER TODAY
AND TONIGHT...BRINGING A CHANCE FOR SOME THUNDERSTORMS THIS
AFTERNOON AND INTO TONIGHT. SOME OF THESE THUNDERSTORMS MAY BECOME
SEVERE...WITH THE THREAT OF DAMAGING WINDS AND LARGE HAIL...AND
POSSIBLY AN ISOLATED TORNADO. THE GREATEST THREAT OF ANY SEVERE
THUNDERSTORMS WILL BE OVER AND NEAR THE PLATEAU AND SOUTHEAST
TENNESSEE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A LOW PRESSURE SYSTEM WILL APPROACH THE SOUTHERN APPALACHIAN
REGION ON SATURDAY NIGHT...BRINGING ANOTHER CHANCE FOR SEVERE
THUNDERSTORMS SATURDAY NIGHT OR SUNDAY. THE GREATEST THREAT OF
SEVERE THUNDERSTORM IS EXPECTED TO BE OVER SOUTHEAST TENNESSEE AND
EXTREME SOUTHWEST NORTH CAROLINA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING...AND
POSSIBLY AGAIN THIS WEEKEND.