Severe Thunderstorm Warning 61, NWS Blacksburg, VA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1045 AM EDT SAT MAY 27 2000

RNK WILL BE DOING A SPECIAL 18 UTC BALLOON RELEASE.

INGREDIENTS HAVE COME TOGETHER FOR SEVERE WX FOR BOTH TODAY AND
SUNDAY.  EAST/WEST BAROCLINIC ZONE WILL BE THE FOCUS FOR
THUNDERSTORMS TODAY.  UPPER LEVEL LOW DROPPING SOUTHEAST ALONG
EAST/WEST BOUNDARY WILL BE THE FOCUS FOR MORE STORMS ON SUNDAY.

A WARM FRONT THIS MORNING WAS LIFTING NORTH INTO THE LOWER OHIO
VALLEY AND MID ATLANTIC STATES.  BOUNDARY BY THIS AFTN IS FCST TO
RUN NW-SE ALONG A HTS-ROA-DAN LN WITH A 65 DEG PLUS DEWPOINT AIRMASS
TO ITS SOUTH.  MCS OVER ERN KY AND WRN WV SEEMS THE FEATURE TO WATCH
AS IT SLIDES ESE ALONG THE WARM FRONT...AND IT WILL BE FEEDING OFF
THE EVER INCREASING INSTABILITY SOUTH OF THE WARM FRONT DURING THE
AFTN.

REGIONAL SOUNDINGS INDICATE FAST FLOW WITH MAINLY UNIDIRECTIONAL
WINDS WEST OF THE BLUE RIDGE...AND SOME DIRECTIONAL SHEAR EAST OF
THE BLUE RIDGE...OBSERVED 0-3KM HELICITY AT GSO WAS 250. SBCAPES
THIS AFTERNOON SHOULD EASIALLY REACH 2500 J/KG ACROSS NC AS TEMPS
CLIMB INTO THE MID 80S AND SFC DEWPOINTS RECOVER TO NEAR 70.  THERE
WAS A WEAK CAP AT AROUND 780 MB IN THE GSO SOUNDING...AND THIS WILL
EASIALLY BE BROKEN BY OUTFLOW FROM THE KY/WV MCS.  FCST 850-500 MB
LAPSE RATES OF 6+ SHOULD SUSTAIN THIS MCS AS IT MOVES EAST WITH THE
POTENTIAL OF IT GOING ALL THE WAY TO THE COAST BY THIS EVENING.

PER SPC DSCN FAST UNIDIRECTIONAL WINDS AND STEEP LAPSE RATES WILL
CONTRIBUTE TO BOW ECHO TYPE STORMS THIS AFTERNOON.  BASED ON THE
SHEAR PROFILES EAST OF THE BLUE RIDGE I ALSO FEEL THERE IS THE
POTENTIAL FOR SUPERCELLS WITH ISOLATED TORNADOES.  WILL UPDATE THE
SEVERE WX POTENTIAL AROUND NOON TODAY RELECTING ALL OF THESE POINTS.

.RNK.
.VA...NONE.
.WV...NONE.
.NC...NONE.

PM

NCZ001>006-018>020-VAZ007-009>020-022>024-032>035-043>047-058-059-
WVZ042>045-271800-

SEVERE WEATHER POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
1230 PM EDT SAT MAY 27 2000

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT...

THUNDERSTORMS OVER WEST VIRGINIA WILL CONTINUE TO TRACK EASTWARD
...AND REDEVELOP EAST OF THE BLUE RIDGE THIS AFTERNOON AND CONTINUE
INTO TONIGHT. A FEW OF THE THUNDERSTORMS COULD BECOME SEVERE. THE
GREATEST THREAT FOR SEVERE WEATHER WILL EXIST ALONG AND SOUTH OF A
WARM FRONT THAT IS EXPECTED TO LIFT NORTHWARD AND EXTEND ALONG A
LINE FROM NEAR BLUEFIELD TO ROANOKE TO LYNCHBURG.  THE GREATEST
THREAT FROM THE STORMS WILL BE LARGE HAIL AND DAMAGING WINDS...BUT
ISOLATED TORNADOES ARE POSSIBLE ACROSS SOUTHSIDE VIRGINIA AND
NORTHWESTERN NORTH CAROLINA.

IN ADDITION...THE ATMOSPHERE IS VERY MOIST AND SOME OF THE
THUNDERSTORMS WILL CONTAIN TORRENTIAL RAIN. PONDING OF WATER ON
ROADS...LOW LYING AND POOR DRAINAGE AREAS COULD OCCUR IN THE HEAVIER
RAIN.

SKYWARN ACTIVATION WILL LIKELY BY NEEDED THIS AFTERNOON.

PLEASE STAY TUNED TO NOAA WEATHER RADIO FOR FUTURE FORECAST
UPDATES... OR IF ANY WATCHES OR WARNINGS ARE ISSUED.

NOGUEIRA