Lightning Strike in North Carolina, December 21, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
114 PM EST WED DEC 21 2011

.SYNOPSIS...
A WEAK COOL FRONT WILL REMAIN STALLED OVER THE REGION AS AN AREA OF
LOW PRESSURE MOVES NORTHEAST ALONG IT. THIS WILL RESULT IN UNSETTLED
WEATHER CONDITIONS LINGERING THROUGH THURSDAY NIGHT BEFORE DRIER AIR
SPREADS IN ON FRIDAY. DRY HIGH PRESSURE ON SATURDAY WILL GIVE WAY TO
ANOTHER INCREASE IN MOISTURE AND RAIN CHANCES BY CHRISTMAS DAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
AT 1245 PM...THE UPPER WAVE MOVING NE INTO THE GREAT LAKES REGION
CONTINUES TO DEAMPLIFY THIS AFTN. THE NEXT SRN STREAM SYSTEM IS
DIGGING TOWARD W TX...AND THE INTERACTION OF THESE FEATURES WILL
KEEP A DEEP LAYER MOIST SW FLOW ACROSS THE REGION THROUGH THE
PERIOD. THE UPPER FEATURES WILL ALSO KEEP A STRONG UPPER JETLET
STRETCHED FROM THE CENTRAL APPLACHIANS TO THE MID MS RIVER
VALLEY...WITH OCCASIONAL DIVERGENCE SE OF THE JETLET AFFECTING THE
FORECAST AREA THROUGH THE PERIOD. MEANWHILE...THE SFC COLD FRONT
MOVING INTO THE SPINE OF THE MTNS LATE TODAY WILL LAY OVER INTO THE
REGION AND STALL OVERNIGHT. ANY PRE/FRONTAL CONVECTION MAKING A RUN
TOWARD THE AREA FROM CENTRAL GA THROUGH EARLY EVENING SHOULD WEAKEN
AS IT ENCOUNTERS SLIGHTLY MORE STABLE AIR. OTHERWISE...EVENING POPS
WILL BE SLOWLY PARED DOWN FROM THE WEST...WITH PRECIP ENDING BRIEFLY
IN THE EARLY MORNING HOURS. MID LEVELS WILL DRY OUT RAPIDLY FROM THE
WEST TONIGHT AND DENSE FOG COULD BECOME A PROBLEM OVERNIGHT IF THE
SFC WINDS MANAGE TO DECOUPLE. WILL MENTION AREAS OF FOG OR DENSE FOG.

THE MODELS FEATURE GOOD AGREEMENT ON SFC WAVE DEVELOPMENT ALONG THE
WRN GULF COAST LATE TONIGHT. THIS WAVE SHOULD ROCKET NE ALONG THE
STALLED FRONTAL BOUNDARY TO A POSITION JUST W OF THE APPALACHIANS BY
LATE DAY. MOISTURE AND PRECIPITATION AHEAD OF THIS FEATURE SHOULD
SURGE BACK IN FROM THE S QUITE RAPIDLY ON WARM ADVECTION FLOW THU.
THE BEST SFC BASED INSTABILITY SHOULD BE IN SW MTN LOCATIONS WHERE
GREATER LOW LEVEL THETA E MAY POOL NEAR THE APPROACHING SFC WAVE.
THE BEST SVR TSTM CHANCES APPEAR TO BE FARTHER TO THE SW THU...BUT
AN ISOLATED SVR TSTM CANNOT BE RULED OUT IN FAR SW SECTIONS GIVEN
THE BACKING SFC FLOW...IMPROVING SHEAR AHEAD OF THE WAVE...AND
SURGING WARM SECTOR. WILL ADVERTISE A SMALL DIURNAL RANGE ON TEMPS
THROUGH THE PERIOD.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 AM WEDNESDAY...A PREFERENCE FOR THE ECMWF WOULD BRING
THE SURFACE LOW PAST THROUGH THE GREAT VALLEY OF TN THURSDAY
EVENING...SO EXPECT CONTINUED WARM ADVECTION/UPGLIDE ACROSS MOST
OF THE FCST AREA THROUGH THE EVENING. THE LOW SHOULD PULL AWAY TO
THE N OR NE EARLY FRIDAY MORNING...DRAGGING THE SURFACE FRONT
BEHIND IT AND ACROSS THE FCST AREA IN THE PRE-DAWN HOURS.
THUS...AS QUICKLY AS THE POP RAMPED UP...IT RAMPS BACK
DOWN...FAVORING ONLY A CHANCE OVER THE PIEDMONT BY SUNRISE FRIDAY.
THAT PRECIP CHANCE CONTINUES TO TAIL OFF TO SLIGHT CHANCE IN THE
AFTERNOON E OF I-85 IN CASE THE FRONT DOES NOT MAKE AS MUCH
EASTWARD PROGRESS AS EXPECTED. HIGH TEMPS HAVE BEEN NUDGED UPWARD
A DEGREE OR TWO TOWARD THE GUIDANCE BLEND.

CONFIDENCE PLUMMETS THEREAFTER. THE FRIDAY NIGHT AND SATURDAY PART
OF THE FCST HAS BEEN VEXING BECAUSE OF POOR CONTINUITY AND
CONSISTENCY IN THE MODEL GUIDANCE. FOR THIS CYCLE...THERE IS GOOD
AGREEMENT AMONG THE OPERATIONAL MODELS THAT THE FRONT WILL MAKE IT
OFFSHORE BY FRIDAY NIGHT AND WE WILL DRY OUT FROM THE NW AT LEAST
BRIEFLY. THE NEW 03Z SREF AGREES...GIVING US ESSENTIALLY A DRY FCST
FRIDAY NIGHT AND SATURDAY. THIS FLIES IN THE FACE OF THE PREVIOUS
FCST GUIDANCE...WHICH WAS HIGH CHANCE TO LIKELY FOR SATURDAY.
AGAIN...A LULL BETWEEN SYSTEMS MAKES SENSE. HOWEVER...WITH SUCH POOR
CONSISTENCY OF LATE...IF WE COMPLETELY ELIMINATE PRECIP CHANCES WE
MIGHT BE BACK IN THE POSITION OF HAVING TO ADD THEM ONCE AGAIN IN
THE NEXT CYCLE. SO...AFTER SOME BRIEF DRYING FRIDAY NIGHT...THE
COMPROMISE WILL BE TO LOWER THE POP TO THE SLIGHT CHANCE RANGE FOR
SATURDAY...WITH THE HOPE THAT CONFIDENCE WILL INCREASE AND ALLOW IT
TO BE ELIMINATED LATER TODAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 320 AM WEDNESDAY...A COMPLICATED WX PATTERN REMAINS IN STORE
FOR THE EXT RANGE. THE LATEST OP MODELS ARE HAVING VARYING IDEAS ON
HOW TO HANDLE THE UPPER SPLIT FLOW...THE AMOUNT OF NRN STREAM
ENHANCING ENERGY MOVING SOUTH AND THE BREAKDOWN AND ALIGNMENT OF THE
SUBTROP HIGH. THERE ARE OTHER DIFFERENCES INCLUDING THE
CONFIGURATION OF THE H3 JET ENTRANCE/EXIT REGIONS...BUT SUFFICE TO
SAY ALL THIS DOESN/T TRANSLATE TO GOOD CONFIDENCE WRT TO THE LLVL
FEATURES NOR THE EXPECTED TIMING AND CHARACTER OF THE SENSIBLE WX.

THE PREVIOUS FCST WAS THUS GIVEN MUCH WEIGHT AND THE BIGGEST CHANGES
MADE WERE TO THE POP GRIDS SAT NIGHT INTO MON. STILL THINK THERE IS
A GOOD CHANCE OF A RELATIVELY WEAK WEDGE IN PLACE BEGINNING SAT
NIGHT AND STRONGER FLOW ASSOCIATED WITH THE MORE AMPLIFIED ECMWF
BRINGS IN A MOIST GOM AIR MASS EARLY...WHILE THE 00Z GFS IS ABOUT 12
HRS LATER WITH MEASURABLE PRECIP REACHING THE WRN ZONES BY 12Z SUN.
THERE IS SOME TOKEN SUPPORT FOR THE GFS SOLN BY THE SLOWEST 00Z CMC
AND THE LATEST STATISTICAL GUIDANCE HAS MADE SIGNIFICANT CHANGES IN
12 HR POPS...SO THE POP GRIDS WERE ADJUSTED DOWN EARLY...WHICH
MATCHES WELL WITH THE SHORT RANGE THINKING...THEN BROUGHT UP TO HIGH
END CHANCE BY SUN AFTERNOON.

PARTIAL THICKNESSES SUGGEST A MARGINAL P/TYPE ISSUE ACROSS THE NC
MTNS SAT NIGHT...BUT FOR NOW IT DOESN/T LOOK LIKE MOISTURE WILL BE
DEEP ENOUGH FOR MUCH IF ANY ACCUM SNOW BELOW 3.5 KFT AS SFC
TEMPS/TDS DONT SUPPORT IT. UP HIGHER...SNOW MAY REACH ADVISORY
LEVELS BY SUN NIGHT...BUT IT REALLY IS TOO EARLY TO TELL SINCE MODEL
THERMAL CONSENSUS IS HIGHLY LACKING.

EXPECT MAX TEMPS TO BE THE COLDEST SUN WITH CLOUDS AND N/LY OR
PERHAPS NE/LY WEDGE TYPE FLOW KEEPING HIGHS A COUPLE DEGREES BELOW
NORMAL. A SLOW AND WEAK WARM UP TO AROUND NORMAL IS PROBABLE MON AND
TUE AS THE SYSTEM MOVES EAST OF THE AREA AND INSOLATION INCREASES.
THE LATTER PART OF THE EXT RANGE REMAINS DRY AND WARMER...BUT THIS
COULD CHANGE TO MORE OF A WET AND COLD PATTERN SINCE THERE IS
EVIDENCE OF ANOTHER SRN STREAM OR A GOM SYSTEM IMPINGING ON THE AREA
WED AND THU.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...PRECIPITATION SHOULD REMAIN FAIRLY WIDESPREAD AROUND KCLT
THROUGH THE LATE AFTERNOON HOURS AS WARM ADVECTION SLOWLY WEAKENS
BUT UPPER JETLET SUPPORT LINGERS OVERHEAD. SOME MIXING HAS DEVELOPED
WITH ASSOCIATED SW GUSTS...BUT CIGS WILL LIKELY REMAIN IN THE IFR
RANGE THROUGH THE LATE AFTERNOON HOURS BEFORE FALLING BACK THROUGH
IFR TO LIFR/VLIFR OVERNIGHT AS MID LEVEL DRYING WORKS IN ATOP THE
MOIST BL. AFTER AN OVERNIGHT LULL IN PRECIP...SHOWERS WILL LIKELY
RETURN FROM THE S LATE IN THE PERIOD. SLIGHT IMPROVEMENT IN CIGS IS
POSSIBLE LATE THU MORNING...BUT STILL IFR THROUGH THE END OF THE
PERIOD. OTHER THAN GUSTS THROUGH 22Z TODAY...EXPECT S TO SW WINDS AT
LESS THAN 10 KT.

ELSEWHERE...PRECIPITATION AROUND THE TERMINAL FORECAST AREA HAS
GENERALLY TAPERED OFF TO LIGHT RAIN THIS AFTN AS THE WARM ADVECTION
AND APPROACHING FRONTAL ZONE FORCING SLOWLY WEAKEN. UPPER JETLET
SUPPORT ALOFT WILL LIKELY KEEP PRECIP GOING...AND THE VERY MOIST
BOUNDARY LAYER SHOULD KEEP CIGS MAINLY IFR THROUGH LATE DAY DESPITE
SOME MIXING. KFFC RADAR SHOWS SOME BETTER PRE FRONTAL CONVECTION
DEVELOPING UPSTREAM...BUT THIS SHOULD WEAKEN BY EVENING SINCE SFC
BASED INSTABILITY IS LESS NEARER OUR TAF SITES. EXPECT A TRANSITION
BACK INTO LIFR/VLIFR OVERNIGHT...WITH DENSE FOG A POSSIBILITY
THROUGH THE EARLY MORNING HOURS IF SFC WINDS CAN SUFFICIENTLY
DECOUPLE. ONLY MARGINAL IMPROVEMENT IN IFR CIGS IS EXPECTED LATE THU
MORNING...WITH RAIN/SHOWERS REDEVELOPING FROM THE S LATE IN THE
PERIOD. OTHER THAN ISOLATED GUSTS LATE THIS AFTN...EXPECT MAINLY
LIGHT S TO SW FLOW AT THE TAF SITES.

OUTLOOK...LOW PRES RIDING NWD ALONG A STALLED FRONT WILL KEEP
CONDITIONS VERY MOIST THROUGH THU NIGHT...BUT WITH BETTER DRYING NOW
EXPECTED ON FRI INTO SAT. MOISTURE MAY RETURN AHEAD OF A GULF COAST
SYSTEM SAT NIGHT INTO SUN.

AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...

WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

SYNOPSIS...CSH
NEAR TERM...HG
SHORT TERM...PM
LONG TERM...SBK
AVIATION...HG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
537 AM EST WED DEC 21 2011

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-221045-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-AVERY-ALEXANDER-
IREDELL-DAVIE-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-CATAWBA-
ROWAN-GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-
HENDERSON-CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION NC-
CALDWELL MOUNTAINS-GREATER CALDWELL-BURKE MOUNTAINS-GREATER BURKE-
MCDOWELL MOUNTAINS-EASTERN MCDOWELL-RUTHERFORD MOUNTAINS-
GREATER RUTHERFORD-POLK MOUNTAINS-EASTERN POLK-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-GREATER OCONEE-
GREATER PICKENS-GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-
ANDERSON-ABBEVILLE-LAURENS-UNION SC-CHESTER-GREENWOOD-
537 AM EST WED DEC 21 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST GEORGIA...PIEDMONT
NORTH CAROLINA...WESTERN NORTH CAROLINA AND UPSTATE SOUTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

A FEW THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND
EVENING...MAINLY ACROSS NORTHEAST GEORGIA...THE MOUNTAINS OF
NORTH CAROLINA...AND UPSTATE SOUTH CAROLINA SOUTH OF INTERSTATE
85. SOME OF THE THUNDERSTORMS MAY CONTAIN STRONG WIND GUSTS AND
HEAVY DOWNPOURS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
926 AM EST WED DEC 21 2011

NCZ051-058-211515-
GRAHAM-SWAIN-
926 AM EST WED DEC 21 2011

...A THUNDERSTORM WITH GUSTY WINDS WILL AFFECT GRAHAM AND SWAIN
COUNTIES THROUGH 1015 AM EST...

AT 925 AM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
THUNDERSTORM 4 MILES SOUTHWEST OF TAPOCO...OR 10 MILES NORTHWEST OF
ROBBINSVILLE...MOVING NORTHEAST AT 50 MPH.

THIS STORM WILL BE NEAR...
  FONTANA VILLAGE...
  FONTANA LAKE...
  SMOKEMONT...

WIND GUSTS UP TO 40 MPH MAY BE CHANNELED TO THE SURFACE FROM THIS
WEAK THUNDERSTORM.

LAT...LON 3537 8401 3541 8403 3553 8388 3553 8383
      3557 8377 3557 8349 3562 8344 3567 8334
      3566 8330 3569 8327 3567 8318 3565 8320
      3563 8317 3559 8319 3536 8359 3528 8401
      3533 8405

HG