[BNAWX] Severe Thunderstorm Warning

[Nashville EMWIN]

WUUS54 KOHX 202045
SVRBNA
TNC031-202115-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NASHVILLE TN
345 PM CDT FRI AUG 20 2004

THE NATIONAL WEATHER SERVICE IN NASHVILLE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN COFFEE COUNTY IN TENNESSEE
  THIS INCLUDES THE CITY OF MANCHESTER

* UNTIL 415 PM CDT

* AT 337 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR TULLAHOMA...OR ABOUT 7
  MILES NORTHEAST OF LYNCHBURG...AND MOVING NORTHEAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  MANCHESTER BY 355 PM CDT

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM W

****ERROR: INCOMPLETE DATA

 DRY.  SHOULD BE AT LEAST SOME
CLOUD COVER AROUND WHICH WILL KEEP TEMPERATURES FROM TAKING A NOSE
DIVE.  ON SATURDAY...MODELS CONTINUE TO ADVERTISE WARMER AND DRIER
CONDITIONS...THOUGH CROSS SECTIONS KEEP ENOUGH MID LEVEL MOISTURE IN
PLACE. SURFACE LEE TROUGH DEVELOPS ALONG FOOTHILLS AND SLIDES EAST
DURING DAY.  THIS SHOULD ALLOW FOR DRIER DOWNSLOPE AIR TO
PUSH ACROSS PLAINS.  THERE COULD BE SOME SORT OF DRY LINE SET UP
BY LATE AFTERNOON SOMEWHERE NEAR AN AKRON TO LIMON LINE.  WITH
DAYTIME HEATING...SHOULD SEE DEVELOPMENT OF AFTERNOON THUNDERSTORMS.
MODELS HINT AT A PASSING SHORTWAVE...WHICH MAY AID IN ADDITIONAL
CONVECTION. CURRENT POPS FOR MOUNTAINS AND FOOTHILLS SEEM IN ORDER.
AS FOR PLAINS...WILL LOWER POPS MOST AREAS...EXCEPT FAR EASTERN
ZONES.  TEMPERATURE GRIDS LOOK REASONABLE BASED ON GUIDANCE AND
THICKNESS PROGS.

.LONG TERM DISCUSSION...SUNDAY THRU TUESDAY...UPPER RIDGE OVER THE
GREAT BASIN SLOWLY FLATTENS AS IT MIGRATES EASTWARD ACROSS COLORADO
DURING THE WEEKEND. A LEE TROUGH ALSO FORMS EAST OF THE MTNS ON
SATURDAY. W/SWLY FLOW NEAR THE GROUND AND LIGHT NWLY FLOW ALOFT
BECOMING ZONAL ON SUNDAY SHOULD RESULT IN DRIER AND WARMER
CONDITIONS ACROSS THE PLAINS OVER THE WEEKEND...MORE SO ON SUNDAY.
TEMPERATURES SLOWLY RETURN TO NEAR NORMAL BY SUNDAY WITH 700 MB
TEMPERATURES PUSHING 13C BY 00Z/MONDAY. SMALL WAVES OF MOISTURE AND
INSTABILITY EMBEDDED WITHIN THIS NEARLY ZONAL FLOW SHOULD RESULT IN
AT LEAST A 20 PCT PRECIP PROBABILITY FOR THE MTNS AND FOOTHILLS.
CURRENTLY MTN AND FOOTHILL ZONES HAVE 30 PCT POPS. THINKING ABOUT
LEAVING 30 POPS FOR SATURDAY...BUT LOWERING POPS TO 20 PCT ON SUNDAY
AND EVEN LESS OF A CHANCE IN THE HIGH MTN VALLEYS AS THE ATMOSPHERE
LOOKS EVEN DRIER AND A BIT MORE STABLE AT MID-LEVELS.   ON THE
PLAINS...WILL GO WITH A SIMILAR REDUCTION IN PRECIPITATION CHANCES
OVER THE WEEKEND. WILL LEAVE 20 PCT POPS IN FOR SATURDAY TO ACCOUNT
FOR A STRAY HEAT GENERATED T-STORM...THEN REDUCE POPS BY 10 PCT FOR
SUNDAY AND EVEN REMOVE MENTION OF PRECIPITATION IN ZONES IN THE NE
CORNER.

ON MONDAY...TEMPERATURES CONTINUE TO RISE AHEAD OF A BROAD MID/UPPER
LEVEL TROUGH CURVING OUT OVER THE PAC NORTHEAST AND ACROSS THE NRN
ROCKY MTNS. WITH 700 MB TEMPERATURES UP AROUND 15C MONDAY COULD SEE
SFC TEMPS REACHING MID AND UPPER 80S...POSSIBLY AROUND 90 OUT NEAR
THE NORTHEAST BORDER AND ALONG THE SOUTH PLATTE. AS FOR PRECIP
CHANCES...BOTH ETA AND GFS SHOW MODEST MID-LEVEL QG ASCENT EAST OF
THE MTNS LATE MONDAY AFTERNOON AND EVENING ASSOCIATED WITH PASSAGE
OF A WEAK SHORTWAVE. FAVORABLE LOW LEVEL SHEAR AND ELEVATED CAPES
ALONG WHAT APPEARS TO BE A SW-TO-NE ORIENTED SFC TROUGH MAY SUPPORT
A FEW STRONG STORMS ALONG AND EAST OF THIS BOUNDARY. WEST OF THE
THIS BOUNDARY W/SWLY DOWNSLOPE FLOW MAY PRETTY LIMIT ANY CHANCE OF
T-STORM DEVELOPMENT AS PRECIPITABLE WATER VALUES THERE DIP BELOW A
HALF INCH AND SFC-500 MB TEMP-DEWPOINT SPREADS BECOME QUITE LARGE BY
AFTERNOON. TUESDAY LOOKS DRIER AND SLIGHTLY WARMER WITH DRY WLY FLOW
SPREADING OUT ACROSS THE PLAINS. 10 PCT POPS ON THE PLAINS MAY EVEN
BE A BIT TOO AMBITIOUS. SLIGHT CHANCES LOOK OKAY FOR THE HIGH
COUNTRY.

WEDNESDAY AND BEYOND...BY MID-WEEK GFS SHOWS GEO-POTENTIAL HEIGHTS
STARTING TO FALL AS THE 500 MB LOW CENTER MOVES INLAND OVER
WASHINGTON. MODEL SOUNDINGS INDICATE AN INCREASE IN MID AND UPPER
LEVEL MOISTURE WITH MODERATELY STRONG SWLY FLOW AHEAD OF THE 500 MB
TROUGH AXIS. THE INCREASE IN CLOUD COVER ENOUGH TO LOWER SFC TEMPS A
FEW DEGS ON WEDNESDAY. THURSDAY AND FRIDAY...MEDIUM RANGE MODELS
CONTINUE TO DIG PACIFIC NORTHWEST COAST TROUGH SEWRD ACROSS THE
CENTRAL ROCKY MTN REGION BY FRIDAY. GFS ALSO HINTS AT PASSAGE OF A
COLD FRONT LATE THURSDAY OR FRIDAY MORNING. TOO FAR OUT TO HAVE A
WHOLE LOT OF CONFIDENCE IN ALL THIS...BUT WILL CONTINUE TO TREND
TEMPS SLOWLY DOWNWARD AND RISE POPS SOME IN LATER PERIODS.

&&

.BOU...NONE.

&&
D-L/BAKER



This weather bulletin was brought to you by:
www.nashvilleweather.net