Severe Thunderstorm Warning 216, NWS Morristown, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
945 AM EDT FRI AUG 16 2002

THE FOLLOWING ARE ALL THE FORECAST DISCUSSIONS FROM THE PAST 24
HOURS...WITH THE MOST RECENT ON TOP. THIS PROVIDES A HISTORY OF THE
DEVELOPMENT OF THE CURRENT FORECAST.

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LATE MORNING FORECAST DISCUSSION
945 AM EDT FRI AUG 16 2002

PLUME OF TROPICAL MOISTURE CONTINUES TO PULL NORTHEAST INTO THE
SOUTHERN APPALACHIANS THIS MORNING WITH PWS NEAR 1.8 INCHES AND
K-INDICES IN THE MID 30S.  AREA SOUNDINGS SHOW AIRMASS A LITTLE
MORE BOUYANT THAN YESTERDAYS WITH CAPES BETWEEN 2000-2500 J/KG
FOR THIS AFTERNOON WITH LIFTED INDICES RANGING FROM -3 TO -5.

HOWEVER...CURRENT CLOUD COVER WILL LIMIT HEATING UNLESS BREAKS
OCCUR THIS AFTERNOON.  NO REAL UPPER FORCING NOTED WITH ONLY LIFT
COMING FROM LOCAL TERRAIN FEATURES.  GIVEN DEGREE OF MOISTURE AND
POTENTIAL INSTABILITY THIS AFTERNOON...PLAN ON CONTINUING WITH
LIKELY POPS.  ALSO...HIGHS PWS SUPPORT MENTIONING LOCALLY HEAVY
RAINS IN THE FORECAST AS WELL.

PLAN ON MAKING COSMETIC CHANGES TO FORECAST AS WELL.

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

DH

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EARLY MORNING FORECAST DISCUSSION
305 AM EDT FRI AUG 16 2002

SOUTHWEST FLOW CONTINUES TO BRING LARGE AMOUNTS OF MOISTURE INTO THE
REGION.  LIMITING FACTOR FOR PRECIPITATION IS TRIGGERING MECHANISM.
INCREASING POPS TODAY TO 60 PERCENT WITH 30S AND 50S THROUGH
WEEKEND.  WENT A LITTLE ABOVE GUIDANCE TEMPERATURES TODAY BASED ON
PREVIOUS DAYS EXPERIENCES.

MODELS IN CLOSE AGREEMENT OVER NEXT FEW DAYS SO ONLY MINOR
VARIANCE.

CHA   87  71  86  71 /  60  30  50  30
TYS   85  70  85  70 /  60  30  50  30
TRI   85  68  83  67 /  60  30  50  30
OQT   85  70  85  70 /  60  30  50  30

*********************************************************************
EVENING FORECAST DISCUSSION
900 PM EDT THU AUG 15 2002

CURRENT RADARS SHOW A FEW SHOWERS AND TSTORMS CONTINUING ACROSS THE
FORECAST AREA THIS EVENING...WITH THE OVERALL AREAL COVERAGE
GRADUALLY DIMINISHING WITH THE SETTING OF THE SUN. THIS EVENINGS
SOUNDINGS CONTINUE TO REVEAL A VERY MOIST AND MODERATELY UNSTABLE
ATMOSPHERE ACROSS THE REGION. THUS...ISOLATED CONVECTION WILL BE
POSSIBLE OVERNIGHT...WITH PATCHY FOG LIKELY DEVELOPING ACROSS AREAS
THAT EXPERIENCED RAINFALL.

WILL PLAN TO UPDATE THE FORECAST THIS EVENING TO MENTION ONLY
ISOLATED CONVECTION OVERNIGHT...AND TO ADD A MENTION OF PATCHY FOG TO
ALL ZONES. TEMPS LOOKS FINE AND WILL NOT CHANGE.

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

DMG

*********************************************************************
AFTERNOON FORECAST DISCUSSION
300 PM EDT THU AUG 15 2002

IN THE SHORT-TERM...NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE
HIGHER TERRAIN (PLATEAU AND FAR EASTERN TENNESSEE MOUNTAINS) WITH
WIDELY SCATTERED TO SCATTERED IN THE VALLEY.  FEEL MORE ACTIVITY WILL
DEVELOP OVER THE VALLEYS LATER TODAY/EVENING.  WILL CALL FOR
SCATTERED STORMS...MAINLY THIS EVENING. EXPECT COVERAGE TO LESSEN
ONCE DAYTIME HEATING IS GONE...BUT WIDELY SCATTERED SHOWERS/STORMS
ARE POSSIBLE OVERNIGHT.

MAIN THREAT WILL CONTINUE TO BE LOCALIZED HEAVY RAINS AND POTENTIAL
TRAINING OF STORMS.

MODELS SHOW SHEAR AXIS/WEAK TROUGH OVER THE LOWER MISSISSIPPI VALLEY
WEAKENING THE NEXT TWO DAYS AS SOME OF THE ENERGY IS PULLED
NORTHEAST FROM NORTHERN STREAM SHORT-WAVES.  HOWEVER...TROPICAL
MOISTURE SEEMS TO REMAIN UNTIL FRONT MOVES INTO THE TENNESSEE VALLEY
FOR SUNDAY.  WILL CONTINUE WITH 50-60 PERCENT POPS FOR MAINLY
AFTERNOON AND EVENING STORMS THE NEXT TWO DAYS WITH 30 PERCENT
DURING THE NIGHT.  THE HIGHER POPS REMAIN IN THE MOUNTAINS AS MAIN
LIFT THROUGH SATURDAY REMAINS OROGRAPHIC LIFT.

FCSTID =
CHA   72  88  72  88 /  30  60  30  50
TYS   71  87  70  87 /  30  50  30  50
TRI   67  86  67  86 /  30  50  30  50
OQT   71  86  70  87 /  30  60  30  50

DH