Flash Flood in Virginia, August 16, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
408 AM EDT SAT AUG 16 2003

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

*********************************************************************

EARLY MORNING FORECAST DISCUSSION
408 AM EDT SAT AUG 16 2003

LOTS OF SHOWERS AND STORMS ONGOING IN THE NE DUE TO UPPER LEVEL VORT
MAX MOVING SE ACROSS KY AT THIS TIME.  SHOULD SEE BULK OF ACTIVITY
MOVE OUT BY 7 AM OR SO.  OTHERWISE...WILL SEE A CHANCE OF SHOWERS
AND STORMS AREAWIDE THIS AFTERNOON IN POSSIBLE REDEVELOPMENT OF
ACTIVITY IN UNSTABLE AIRMASS.  NO VORT AS STRONG AS THIS PROGGED TO
COME THROUGH THIS AFTERNOON...AND THE LACK OF UPPER LEVEL SUPPORT
MAY INHIBIT OR LIMIT AFTERNOON ACTIVITY.  MODELS DISAGREE ON HOW
CONVECTIVE SITUATION WILL EVOLVE...BUT NEITHER ONE HAS BEEN THAT
GOOD LAST FEW DAYS ANYWAY.  BEST BET FOR CONVECTION LIKELY TO BE
SUNDAY AS FRONT MOVES THROUGH THE AREA...BUT UPPER LEVEL SUPPORT
DOES NOT LOOK APPEAR TO BE TIMED WELL WITH SURFACE FEATURE...SO HAVE
SLIGHTLY UNDERCUT GUIDANCE AT THIS TIME.  SUSPECT MAY NEED TO RAISE
SUNDAY POPS WITH LATER PACKAGES...BUT CONFIDENCE LOW AT THIS POINT.

MAX TEMPERATURES HAVE GONE ABOVE GUIDANCE LAST TWO DAYS...AND AM
BETTING ON THAT TO OCCUR AGAIN TODAY EXCEPT IN NE WHERE CONVECTIVE
DEBRIS AND VERY WET GROUND SHOULD LIMIT HEATING.

WILL NEED TO UPDATE AROUND 7 AM AND MAKE SMALL ADJUSTMENTS DEPENDING
ON WHAT CONVECTION DOES BETWEEN NOW AND THEN.

CHA   91  72  90  71 /  30  30  30  20
TYS   89  71  88  67 /  30  30  30  20
TRI   84  68  83  62 /  50  40  30  20
OQT   89  71  87  66 /  30  30  30  20

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

SP

*********************************************************************
EVENING FORECAST DISCUSSION (UPDATED)
1015 PM EDT FRI AUG 15 2003

DURING THE AFTERNOON...CONVECTION DOMINATED ON THE HIGHER PLATEAU
TERRAIN AND ACROSS THE SMOKY MOUNTAINS. THIS EVENING CONVERGENCE HAS
SHIFTED INTO THE GREAT VALLEY AS THE HIGH TERRAIN COOLS AND DRAINS.
TSRA ARE FEEDING OFF THE UPR 80 AND 90 DEGREE HEAT OF THE AFTERNOON
PRODUCING SOME SMALL HAIL BUT MAINLY HEAVY RAIN. STILL SOME WEAK VORT
ENERGY TO ROTATE SE INTO FA OVRNIGHT AND IT MAY TAKE A WHILE FOR
CONVECTION TO SETTLE DOWN ACROSS CENTRAL EAST AND SOUTHEAST TN/SW
NC. WILL KEEP SCT POPS GOING FOR THE OVRNITE. NO UPDATES PLANNED

*********************************************************************
AFTERNOON FORECAST DISCUSSION
315 PM EDT THU AUG 15 2003

SHORT TERM...UPPER LEVEL RIDGE IS SLOWING SHIFTING WESTWARD OVER
THE REGION.  THIS HAS ALLOWED A NORTH TO NORTHWESTERLY FLOW
ALOFT TO DEVELOP OVER THE REGION.  A COUPLE OF WEAK DISTURBANCE
IN THIS UPPER FLOW ALONG WITH A CONTINUED MOIST AND WEAKLY
UNSTABLE AIR MASS IN PLACE WILL KEEP A CHANCE OF
SHOWERS/THUNDERSTORMS IN THE FORECAST INTO SUNDAY.  THE TAIL END OF A
WEAK COOL FRONT IS PROGGED THROUGH THE AREA ON SUNDAY. BELIEVE MODELS
MAY BE A BIT FAST WITH THIS FEATURE SO HAVE CONTINUED AT LEAST SOME
PRECIP CHANCES ACROSS THE AREA INTO SUNDAY NIGHT. LITTLE CHANCE IN
TEMPERATURES EXPECTED IN THE SHORT TERM...THOUGH AN INCREASE IN
CLOUDS ON SUNDAY SHOULD PUT HIGHS A DEGREE OR TWO.

EXTENDED...MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT THIS RUN
THROUGH MOST OF THE PERIOD BEFORE DIVERGING SOMEWHAT IN THEIR
SOLUTIONS BY LATE IN THE PERIOD. UPPER FLOW WILL CONTINUE TO AMPLIFY
EARLY NEXT WEEK WITH EAST COAST TROUGH SHARPENING IN RESPONSE TO AN
AMPLIFICATION OF THE CENTRAL PLAINS RIDGE. THIS WILL PUT OUR REGION
UNDER A NORTHWESTERLY FLOW ALOFT. ALL MODELS PROJECT A RELATIVELY DRY
REGIME THROUGH THIS TIME FRAME. FLOW WILL TEND TO DEAMPLIFY BY LATE
IN THE EXTENDED. THE CANADIAN GEM AND ECMWF MODELS SUGGEST A LOW
AMPLITUDE RIDGE WILL BUILD INTO THE SOUTHEAST...ALTHOUGH THE GFS DOES
NOT DEPICT THIS AND MAINTAINS A LOW AMPLITUDE TROUGH. SURFACE COLD
FRONT IS PROJECTED TO MOVE THROUGH THE SOUTHERN APPALACHIANS BY LATE
THURSDAY/EARLY FRIDAY. THIS WILL LIKELY BRING THE BEST CHANCE OF
ORGANIZED PRECIP TO THE AREA DURING THE EXTENDED PERIOD. GENERALLY
FOLLOWED GFS GUIDANCE NUMBERS FOR TEMPS.

PRELIMINARY NUMBERS FOLLOW:

CHA   71  88  70  88 /  30  30  30  30
TYS   69  86  70  86 /  30  30  30  30
TRI   69  83  69  82 /  30  30  40  40
OQT   69  86  70  86 /  30  30  30  30

LCM/MB

*********************************************************************

MID MORNING FORECAST DISCUSSION (UPDATE)
930 AM EDT FRI AUG 15 2003

HIGH PRESSURE RIDGE WILL RETROGRADE WESTWARD TODAY WITH FLOW
ALOFT BECOMING NORTHWESTERLY. HOWEVER...THE ATMOSPHERE WILL REMAIN
MOIST AND WEAKLY UNSTABLE INTO THE WEEKEND...KEEPING A CHANCE OF
CONVECTION OVER THE AREA.  ALL HANDLED WELL IN CURRENT FORECAST...
WILL UPDATE TO REMOVE MORNING WORDING ONLY.

MJB

*********************************************************************

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
231 AM EDT SAT AUG 16 2003

TIME(EDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0215 AM    PINEY FLATS               TN   WIND DAMAGE
08/16/03   SULLIVAN                       A FEW TREES DOWN IN THE
                                          PINEY FLATS AREA.
                                          REPORTED BY SULLIVAN
                                          COUNTY 911.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
319 AM EDT SAT AUG 16 2003

TIME(EDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0220 AM    ELIZABETHTON              TN   WIND DAMAGE
08/16/03   CARTER                         SEVERAL TREES DOWN IN THE
                                          ELIZABETHTON AREA.
                                          REPORTED BY CARTER COUNTY
                                          911.