Severe Thunderstorm Warning 161, NWS Blacksburg, VA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
103 PM EDT SAT JUN 14 2008

.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE REGION FROM THE NW TODAY AND
DRIFT ACROSS THE AREA TONIGHT INTO EARLY SUNDAY. THIS SHOULD
RESULT IN BETTER COVERAGE OF SHOWERS AND THUNDERSTORMS BEFORE
SOMEWHAT DRIER AIR WORKS INTO THE REGION ON SUNDAY. WEAK HIGH
PRESSURE WILL BUILD IN ON MONDAY AHEAD OF ANOTHER COLD FRONT SET
TO SLIDE SE ACROSS THE MID ATLANTIC REGION BY TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
OLD AREA OF PRE-FRONTAL CONVECTION STALLED ACROSS THE WESTERN
SLOPES OF THE APPLNS EARLY THIS MORNING...AND THE WEAK SFC FNT HAS
JUST ABOUT CAUGHT UP WITH IT. AREA RADARS AND VISIBLE SATELLITE
ARE INDICATING THAT THE CONVECTION ACROSS ERN KY IS ALREADY
BEGINNING TO INCREASE IN STRENGTH AND COVERAGE. IN ADDITION...WATER
VAPOR SHOWS A DISTINCT SHORT WAVE NEAR CINCINNATI TRACKING
NORTHEAST OVER THE RIDGE. LINEAR MOTION BRINGS THE SHORT WAVE
ACROSS THE CENTRAL APPLNS AND INTO ERN PA BY LATE AFTERNOON. THIS
FEATURE SHOULD FIRE UP AN ORGANIZED AREA OF CONVECTION AHEAD OF
THE WEAK SFC FNT...AND ALSO GIVE THE SFC FNT A GOOD EASTWARD PUSH-
ESPECIALLY ACROSS THE CENTRAL APPLNS. WITH NEARLY CLEAR SKIES AT
THE MOMENT AND PLENTY OF HEATING...MODIFIED 12Z RNK SOUNDINGS
EASILY GIVES SW VA A CAPE OF 2000 TO 2500 J/KG...BUT WITH FAIRLY
WEAK MID LEVEL LAPSE RATES WEAK SHEAR. MODIFIED GSO SOUNDINGS HAS
EVEN BETTER CAPE OF EASILY AROUND 3000 J/KG...BUT EVEN WEAKER MID
LEVEL LAPSE RATES AND WIND FIELDS. I LIKE THE 12Z NAM DEPICTION OF
A LINE OF TSTMS DEVELOPING AHEAD OF THE SFC FNT IN SW VA AND SRN
WV...AND OTHER TSTMS DEVELOPING ALONG THE BLUE RIDGE IN NW
NC....THEN MOVING BOTH AREAS EASTWARD AND INTO THE PIEDMONT THIS
EVENING. I SEE NO REASON NOT TO RAISE THE POPS TO LIKELY FOR AT
LEAST ALL OF THE MTNS AND FOOTHILLS...AND TO A HIGHER CHC IN THE
PIEDMONT TOWARD EVENING. AS FOR HIGH TEMPS...I HAVE ADJUSTED THEM
UPWARD A FEW DEGREES IN SPOTS...AS MOST LOCATIONS ARE RUNNING
AHEAD OF THE FCST. HOWEVER CLOUDS WILL INCREASE QUICKLY IN THE
AFTERNOON AND CUT OFF HEATING SO I DID NOT GO UP MUCH. FINALLY...I
WILL PROBABLY ADD SOME HEAVY RAIN AND GUSTY WINDS WORDING TO THE
TSTMS SINCE WE WILL HAVE SUCH HIGH CAPES...PWATS WILL BE ABOVE
NORMAL...WARM CLOUD DEPTH 6500 TO 8000 FT AND A POTENTIAL FOR
TRAINING STORMS AS THE SFC FNT MOVES SLOWLY EAST.

CONVECTION SHOULD LINGER OVER THE EAST THIS EVENING BUT PUSH SE A
BIT QUICKER OVERNIGHT ESPCLY IF DRIVEN BY A MORE ORGANIZED TSRA
BAND PER THE NAM. HOWEVER SINCE THE 5H TROF/SUPPORT IS WEAK AND
UPPER RIDGE HANGING TOUGH WILL STAY SLOWER WITH DRYING AND KEEP
LOW POPS SE THRU LATE TONIGHT. SHOULD SEE SOME CLEARING
CENTRAL/WEST TOWARD MORNING AS FLOW TURNS LIGHT NW SO WILL
DECREASE CLOUDS ALL EXCEPT THE PIEDMONT AND FAR NW TOWARD MORNING.

NEED TO TRIM HIGH TEMPS BACK A FEW DEGREES SE WVA TODAY GIVEN
POTENTIAL FOR MORE CLOUDS/SHRA EARLY WHILE KEEPING 80S ELSW OVER
THE WEST...AND 90-95 EAST PER AXIS OF WARMER THICKNESS PIEDMONT.
MOS LOOKS TOO COOL OVERNIGHT UNDER WEAK DRY ADVECTION AND CLOUDS
SO STAYING A CAT ABOVE WITH LOWS MOST SPOTS.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
PASSING WEAK UPPER TROF SHOULD GIVE THE FRONT A BOOST TOWARD THE
COAST SUNDAY TAKING ANY LINGERING SHRA TO THE SE SUNDAY MORNING.
HOWEVER POST FRONTAL SURFACE RIDGE REMAINS QUITE WEAK AND MOISTURE
MAY BE TOUGH TO SCOUR SE WHERE COULD BE ENOUGH CAPE FOR AN
AFTERNOON SHRA SO LEAVING LOW POPS SOUTH/SE. OTRW BECOMING MOSTLY
SUNNY ELSW UNDER WEAK SUBSIDENCE AND NW FLOW. SOMEWHAT COOLER
SUNDAY NIGHT UNDER WEAK HIGH PRESSURE AND MAINLY CLEAR SKIES.

UPPER PATTERN CHANGE BACK TO EASTERN TROFFINESS WILL BEGIN TO TAKE
SHAPE MONDAY PRECEDED BY A STRONGER COLD FRONT THAT WILL QUICKLY
PRESS SE THROUGH THE OHIO RIVER VALLEY BY AFTERNOON. BETTER
DYNAMICS AND WIND FIELDS MAY SUPPORT A MORE ORGANIZED FAST MOVING
AXIS OF CONVECTION ESPCLY GIVEN AFTERNOON TIMING. HOWEVER RH A
LITTLE MORE LIMITED WITH THIS SYSTEM SO THINK BEST
CHANCES FOR CONVECTION WILL BE IN SE WV...WITH AREAL COVERAGE
DIMINISHING UPON MOVING EAST. SOUTHWEST FLOW AND 850 TEMPERATURES
INCREASE TO HAVE SURFACE TEMPERATURES ABOUT 10-15F ABOVE NORMAL.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
REST OF THE WEEK LOOKS TO BE DOMINATED BY NW FLOW AROUND A CHILLY
MID ATLANTIC 5H TROF PRODUCING A NOTED EXTREME IN TEMPS FROM
RECORD HIGHS SEEN A FEW DAYS BACK. THERE STILL WILL BE ISOLATED TO
SCATTERED CONVECTION POSSIBILITIES ACROSS THE MOUNTAINS AS SHORT
WAVES TRACK OVER THE OHIO VALLEY AND INTO THE WESTERN SLOPES OF
THE APPALACHIANS BUT TIMING/LOCATION QUITE IFFY AT THIS POINT.
OTRW HIGHS RANGING FROM THE UPPER 60S TO MID 70S WEST AND MAINLY
70S TO LOW 80S EAST. LOWS IN THE 50S MOST SPOTS WITH SOME 40S
POSSIBLE IN THE VALLEYS.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
NUMEROUS SHOWERS/SCT TSTMS AHEAD OF AN APPROACHING COLD FRONT WILL
BE AFFECTING THE AREA INTO EARLY EVENING. HAVE TRIED TO TIME EACH
TAF SITE FOR THE PERIOD WHEN THEY ARE MOST LIKELY TO SEE A TSTM
WITH A TEMPO GROUP. SHOULD BE MODERATE TO HEAVY RAIN...AND MAY
BRING IFR CONDITIONS...BUT HAVE MOSTLY STAYED MVFR/BORDERLINE IFR
WITH VSBYS. MOST OF THE CONVECTION SHOULD BE EAST OF LYH DANVILLE
BY 00Z. WEAK FLOW BEHIND THIS FRONT MEANS THAT WE WILL LIKELY SEE
FOG DEVELOPING IF WE HAVE AT LEAST PARTIAL CLEARING. IS A GOOD
PATTERN FOR LIFR CONDITIONS AT BOTH BLF AND LWB...SO I HAVE
BROUGHT THEM BOTH DOWN LATE TONIGHT. LYH AND DANVILLE MAY ALSO SEE
LIFR CONDITIONS. I EXPECT ALL SITES TO IMPROVE TO VFR IN THE 13 TO
15Z TIME FRAME WITH DRIER AIR MOVING IN ON A NWRLY FLOW.

HIGH PRESSURE WILL PROVIDE VFR CONDITIONS INTO MONDAY...WITH THE
EXCEPTION OF THE POSSIBILITY OF A PERIOD OF FOG LATE SUNDAY NIGHT
INTO EARLY MONDAY MORNING. ANOTHER WEAK COLD FRONT ARRIVES WITH
POSSIBLY OF MORE SHOWERS OR STORMS LATE MONDAY.

VFR CONDITIONS EXPECTED TUESDAY AND WEDNESDAY WITH A NORTHWEST
FLOW INTO THE REGION. EXCEPTION MAY BE BLF AND LW...WHERE PASSING
SHOWERS COULD BRING BRIEF PERIODS OF MVFR.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

SYNOPSIS...JH/JJ
NEAR TERM...JH/JJ
SHORT TERM...JH/RCS
LONG TERM...JH/RCS
AVIATION...JH/JJ

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
644 AM EDT SAT JUN 14 2008

NCZ001-002-018-VAZ007-009>020-WVZ042>045-151045-
ASHE-ALLEGHANY NC-WATAUGA-TAZEWELL-SMYTH-BLAND-GILES-WYTHE-PULASKI-
MONTGOMERY-GRAYSON-CARROLL-FLOYD-CRAIG-ALLEGHANY VA-BATH-MERCER-
SUMMERS-MONROE-GREENBRIER-
644 AM EDT SAT JUN 14 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHWEST NORTH
CAROLINA...SOUTHWEST VIRGINIA...WEST CENTRAL VIRGINIA AND SOUTHEAST
WEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

ISOLATED STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE AHEAD OF A
COLD FRONT THIS AFTERNOON INTO EARLY THIS EVENING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

ADDITIONAL STRONG TO SEVERE THUNDERSTORMS COULD AFFECT THE AREA
LATE MONDAY INTO MONDAY NIGHT AHEAD OF A MUCH STRONGER COLD FRONT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

NCZ003>006-019-020-VAZ022>024-032>035-043>047-058-059-151045-
SURRY-STOKES-ROCKINGHAM-CASWELL-WILKES-YADKIN-ROANOKE-BOTETOURT-
ROCKBRIDGE-PATRICK-FRANKLIN-BEDFORD-AMHERST-HENRY-PITTSYLVANIA-
CAMPBELL-APPOMATTOX-BUCKINGHAM-HALIFAX-CHARLOTTE-
644 AM EDT SAT JUN 14 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL NORTH
CAROLINA...NORTHWEST NORTH CAROLINA...CENTRAL VIRGINIA...SOUTH
CENTRAL VIRGINIA...SOUTHWEST VIRGINIA AND WEST CENTRAL VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

A FEW STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE AHEAD OF A
COLD FRONT THIS AFTERNOON AND EVENING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.